Critique of Christmas Time in Charles Dickens A...

Critique of Christmas Time in Charles Dickens A Christmas Carol An audience members gleeful first-hand account of Charles Dickenss public reading of A Christmas Carol unwittingly exposes an often overlooked contradiction in the storys climax: Finally, there is Scrooge, no longer a miser, but a human being, screaming at the conversational boy in Sunday clothes, to buy him the prize turkey that never could have stood upon his legs, that bird (96). Perhaps he is no longer a miser but, by this description, Scrooge still plays the role of a capitalist oppressor, commanding underlings to fetch him luxuries. While Dickens undoubtedly lauds Scrooges epiphany and ensuing change, A Christmas Carol also hints at the authors†¦show more content†¦For Dickens, the altruism Christmas breeds is a false exercise in guilt-reduction, and the pat ending of A Christmas Carol reinforces this; the satisfaction of listening to a story whose conclusion is never imperiled (and grows more knowable with each years retelling) spares the reader the self-examinat ion Scrooge endures that a darker turn might provoke. Christmas is only a bright spot if the rest of the year is comparatively dark, and Dickens exposes this contrast through Scrooges nephews optimistic ruminations on Christmas timeÃ…  as a good time: a kind, forgiving, charitable, pleasant time: the only time I know of, in the long calendar of the year, when men and women seem by one consent to open their shut-up hearts freely, and to think of people below them as if they really were fellow-passengers to the grave, and not another race of creatures bound on other journeys. (8-9) The nephews breakdown between Christmas, the only time of the otherwise long calendar, corresponds to Gà ©rard Genettes terms for the narrative techniques singulative and iterative. The narrator is not exempt from optimistically meditating on the benevolent singulative at the expense of the malevolent iterative: And every man on board, waking or sleeping, good or bad,Show MoreRelatedAnalysis Of A Christmas Carol By Charles Dickens1395 Words   |  6 PagesMore than Just a Novel for the Christmas Season Christmas, the most joyous season of the year for many Christians. Yet, in the early Victorian era many industry and business leaders started to emerge as people who lacked the spirit of giving of kindness, particularly around Christmas. Charles Dickens, in eighteen forty-three penned a novel that to this day is one of the most beloved books of the Christmas season. Many view the book only as a seasonal novel to read as a young child or even an adultRead MoreThe Life Of Charles Dickens A Christmas Carol1062 Words   |  5 PagesThe Victorian Period lasted from 1832 to 1901 under Queen Victoria’s reign. The culture revealed in this era was a time of rapid change, social inequality, industrialization, supernatural and religious beliefs, and was accurately reflected in the works of Charles Dickens, A Christmas Carol. Roles of men and women were strictly defined, as were economic statuses. The hustle and bustle of the streets led to illnesses. Working conditions were destitute and unsanitary. Children often had little to noRead Moreignorance and want875 Words   |  3 PagesSet up against the rampant industrialization of the 18th century, Charles Dickens classic novella â€Å"A Christmas Carol† endorses the notion that all people have a responsibility to ensure the safety and welfare of every member of society. By taking his seemingly irredeemable protagonist Ebenezer Scrooge on an other worldly journey. Dickens intends to convey to the complacent classes of the age, the necessity of various traits that are essential in life, such as the responsibility for those whom areRead MoreThe Main Contributions to Charles Dickens Popularity1592 Words   |  6 Pagescommentary attribute to the widespread popularity that Charles Dickens managed to accumulate even after his death. He has been the subject of countless hours of research, studies, and literary critiques; regardless of one’s personal opinion, it is impossible to doubt the significance of D ickens and his entire collection of work. Mr. Dickens had an inexplicable gift which allowed him to write and convey some of the greatest stories of that time period, as well as having crafted interesting and memorableRead MoreThe Evidence Of Unbound Loyalty1746 Words   |  7 PagesOliver, ill-treated and hungry, approaches his masters saying â€Å"Please, sir, I want some more† (Dickens 11), Charles Dickens enthralls his readers in the harsh, twisted journey of Oliver Twist. Through a series of exciting events full of abuse, loyalty, hatred, and love, Dickens portrays the overlooked difficulties of the poor, lower class that Oliver Twist’s action-packed life has been subject to. Some of Dickens most loved characters, including the adolescent pickpocket under the pseudonym the ArtfulRead MoreCharles Dickens s A Christmas Carol1923 Words   |  8 PagesEnglish author Charles Dickens has written many well known novels such as Oliver Twist and A Christmas Carol, of whi ch both have a recurring theme: the expectations of society. During the Victorian Era, England was over populated and had terrible living conditions, with an enormous gap between the rich and the poor. Generally, people during the Victorian Era were not allowed to talk about things such as sex and crime, and had to live by strict social rules set by society. With the social disparitiesRead MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 PagesThree Ethical Decision Criteria 187 †¢ Improving Creativity in Decision Making 188 Summary and Implications for Managers 190 S A S A S A L L L Self-Assessment Library What Are My Gender Role Perceptions? 166 glOBalization! Chinese Time, North American Time 171 Myth or Science? Creative Decision Making Is a Right-Brain Activity 181 Self-Assessment Library Am I A Deliberate Decision Maker? 183 An Ethical Choice Whose Ethical Standards to Follow? 185 Self-Assessment Library How Creative Am I?

Zionism and the Impact of World War One on the Middle East

The nationalist movement of Zionism emerged out of the Jewish people’s need for a national state of their own. This idea harkens back to the establishment of the Kingdom of Israel after the Exodus. The Holy Land and all of its historic prestige persisted in Jewish culture as they spread throughout the Diaspora for 2000 years. Restrictions and persecution followed the Jewish people as they were met with prejudice throughout Eastern and Western Europe. Organized political Zionism grew from tsarist Russia, where pogroms carried out against the Russian and Polish Jews in the 1880’s killed thousands. Originating in Russia in 1884, an agency named the Lovers of Zion assisted the emigration of Jews to Palestine, where they organized small farms. During this time Leon Pinsker wrote â€Å"Auto-Emancipation†, a Zionist pamphlet in which he posits an answer to the â€Å"Jewish Question†. He argues that Jews are despised all over the world, and are viewed as aliens that cannot be assimilated. He also states, â€Å"Since it is not to be our mission to reform mankind, we must see what we have to do for ourselves under the circumstances.† Another prominent Zionist activist was Theodor Herzel who wrote the â€Å"Jewish State† in 1896, where he asserts that the Jews comprised a nation without a political state. It is important to note that both Pinsker and Herzel did not directly name Palestine as the location for a Jewish state. The following year, Herzel organized the first Zionist Congress in Basel inShow MoreRelatedA Brief Note On The Arab Israeli War1203 Words   |  5 PagesIsraeli Conflict The Middle Eastern area has experienced and suffered more conflict and blood shed than probably any part of the world. The Arab-Israeli war in 1948 was the first step of a century of bloody and hostile conflicts. The Arab- Israeli war was caused by a number of factors both intraregional and international, which created a catalyst of war through a complex situation. This was triggered by Israel’s independence declaration in 14 May 1948; in the Arab-Israeli war the victor was IsraelRead MoreThe Rise Of Zionism And Arab Nationalism1407 Words   |  6 PagesThe rise of Zionism and Arab Nationalism in the nineteenth century triggered major political tensions in the region of Palestine. The conflict among the Zionists and Arab Nationalists is primarily due to the politics of territory and is essentially not comprised of religious opposition. In fact, before the advent of Zionism and Arab Nationalism, Jews and Palestinians shared a local identity due to mutual tolerances. This ident ity, which took precedence over religion, created a vivacious communityRead MoreSuper Power Involvement in the Middle East1401 Words   |  6 PagesUSSR and US were in engaged in a war by proxy, which is very easy to identify if you analyze the conflicts in the Middle East from 1948 until, and including, the Yom Kippur War of 1978. The superpowers would employ tactics such as supplying their various ‘allies’ in the Middle East with weapons and finances which would afford them the ability to engage in the many conflicts that took place in that period such as the Suez Crisis, Six Day War and the Yom Kippur War. All of this was done without eitherRead MoreUS Support for the State of Israel Essay1421 Words   |  6 Pagesâ€Å"Delegitimization: The Jewish State has no right to exist. Israelis do not belong in the Middle East. Double Standards: Israel is condemned harshly for self-defense measures and social problems that are seen as acceptable or inevitable in other nati ons. Demonization: Through distortions and lies, Israel is depicted as the world’s most evil and dangerous country, and the claim is made that if the Jewish State ceased to exist, the middle east’s and the world’s problems would be solved† (Israel 101, 39). In a pollRead MoreBuber And Arendt Approaches To Zionism1360 Words   |  6 PagesIn my paper, I will be compared Buber and Arendt’s approaches to Zionism. Although they both have the same humanist perspective on Zionism, their approaches in their discussion of Zionism is exceedingly different. Therefore, although both Buber and Arendt recognize the importance of incorporating the Palestinians in the process of the creation of a Jewish state, Buber has a more optimistic view than Arendt. However, both Buber and Arendt are critical of nationalism and imperialist power’s influenceRead MoreJew in the Arab World 1071 Words   |  5 Pagesages. As a result of that many of an ethnic group fro m outside Middle East decides to move on to that rich area which later many minorities have spread to the Islamic Empire land therefore The Arabic regions were famous with the diversity of minority which creates a lot of conflict with Middle East region especially in Jews and Arab sides. 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Since then, things have changed greatly, and I don’t believe the conflict between them can currently be solved. The friction between these two countries and religions is still increasing, and so is the hostility that’s contained by the Palestinian people. Israel has committed many human rights violations, including killings, beatingsRead MoreArab, Muslim And Middle East1875 Words   |  8 Pagestopic, we must first define the following terms: Arab, Muslim and Middle East. Millions of the people that fall into these categories live in the United States, yet we har dly take the time to learn to differentiate between them thanks to the negative connotations that are associated with each of these terms (Chin, 2009). To be considered Arab, you or your ancestors live or lived in the Arab world and speak Arabic. The â€Å"Arab world† is made up of 22 states and territories whom are part of the ArabRead MoreThe Difficult History of the Jews Filled with Persecution973 Words   |  4 Pagespersecution, ultimately adding one deadly tenet that all Jews must be eliminated. As the international economic crisis of the Great Depression spread in the early 1930s, the Nazis fed on the discontent of the lower and middle classes of Germany. Most German voters who brought the Nazis to power assumed their extremism would be tempered by the responsibility and compromise necessary to govern. They were mistaken. Jews lost their jobs, their citizenship, and all civil rights. When war broke out in 1939, escape

Camisea Gas Project Free Essays

The already drilled gas extraction operations for â€Å"block 88† wants to expand to destroy even more indigenous native land. The area has suffered a range of direct and â€Å"indirect† impacts, from the loss of local fish and hunting populations on which native indigenous people of that land live on, to landslides, infectious diseases and SST outbreaks. Peruvian health ministry confirmed that incidences of infectious diseases had increased among one group, the Anti, to such a disturbing rate that only one in four now reaches adolescence. We will write a custom essay sample on Camisea Gas Project or any similar topic only for you Order Now Expansion of the gas project is the most damaging project In the Amazon Basin. From the improper development loans, scars to primary rainforest’s, and damage to semi- nomadic peoples who live In Isolation we can see why this Is true. This project has upset many In Peru, especially because It was bullet within the Fracas Marine Reserve, considered to be an internationally Important wetland area by the RAMS. Despite repeated appeals by Peruvian society, the consortium refused to choose an alternative. There was a lot of push back and criticism from indigenous groups, Peruvian society, international Nags, USA congressional representatives and its own environmental auditors. They all agreed that this project would not only harm the people living there, but their own economy and image to the outside world. But even after all the signs they were given not to do it, the Inter-American development bank approved a direct loan of $75 million and a syndicated loan of $60 million to the transportation consortia In September 2003. Evidence from the field indicates that Inter-American Development Bank endorsement effectively gave the project companies a green light to continue even though they knew of the projects flaws. The development bank gave an â€Å"Environmental and Social Impact Assessment Report† woo years after the project had started. Of the reports 138 pages, only 21 actually dealt with environmental and social impacts, and even then they were minimized. In the whole report there was only one paragraph that was about socio-cultural change, one of the biggest issues for the affected communities. The development bank failed to honor loan conditions by refusing to release numerous documents about environmental and social management which in turn made them quickly close their loan provision deal. They didn’t touch on concerns of native rights being abused, local development, or community compensation for the land and lives they strayed. The Seamless gas project certainly left their mark on the Amazon. This Seamless project has without a doubt devastated some of the most diverse and threatened biological ecosystems In the world. The remote, roadbeds, Aruba and Hecatomb regions have been considered by conservationists to be of almost unparalleled biological richness and the pipe is cutting its way through these areas. Migrants, loggers and developers to the area resulting in deforestation, environmental degradation and social pressures on the vulnerable aboriginal communities. The companies in charge have breached both modern industry tankards and international environmental guidelines. The workers do not care for safety and because of this it has led to the death of nine workers and one Machinating child, drowned in the wake of a speeding consortium boat. Technical experts have documented that there are critical impacts to natural habitats because of persistent multiple landslides, massive soil erosion, and river sedimentation from the pipelines extremely steep route. Since the company consistently disregards the erosion control during and after construction, it has allowed heavy rainfall to wash thousands of tons of soil and vegetation into local rivers. This is all unfortunate proof that this expansion of the gas project is scaring the Amazon forest. The Samisen project continues to Jeopardize not only the environment but the health and safety of the Machinating indigenous communities living in small communities along the Aruba and Samisen rivers. The pipeline construction and spills have caused a reduction in fish and animals that the natives need to survive. Illness has increased significantly throughout Aruba. Dozens of cases of syphilis reported by the health post in the indigenous community of Grittier and on top of that, local health rockers testified that small children are at risk from chronic malnutrition. These semi-nomadic peoples live in voluntary isolation and choose to live the way they do, yet companies come in destroying their land and causing sickness. The government of Peru created the reserve in 1990 to protect these vulnerable people from intrusion, but this was obviously recognized as an international violation of indigenous rights. Forty-two percent of the Nah population had already died from introduced diseases which they have no immunity to when shell conducted gas exploration in he mid-asses. The Nah took a first-time step of publicly communicating through local advocates their rejection of all oil and gas operations within their lands: â€Å"In the past, Shell worked here and almost all of us died from the diseases†¦ We know that if another company comes here, our rivers and land will be destroyed. What will we eat when the rivers are dead and the animals run away? ‘ Looking at the impacts that this project has done to the Peruvian Amazon, it’s easy to say it has not benefited anything other than the fact that the company gets their money. Its improper loans room the inter-American development bank, damages to one of the most biological sound places on earth, and the lasting effects it has on the indigenous peoples all play a part in this destruction of the nature of the Amazon. If we could somehow take a look at how the Amazon would have turned out if it was UN-touched by this project, we might find the indigenous people still living in their voluntary isolation, with no increase in deaths to their population and no harm to their reserve, but unfortunately this is not the case. Without a doubt the expansion of this gas project has been the most damaging project in the Amazon Basin. How to cite Camisea Gas Project, Papers

Analysis of International Law Essay Example For Students

Analysis of International Law Essay International law is the body of legal rules that apply between sovereign states and such other entities as have been grantedinternational personality (status acknowledged by the international community). The rules of international law are of a normativecharacter, that is, they prescribe towards conduct, and are potentially designed for authoritative interpretation by an international judicial authority and by being capable of enforcement by the application of external sanctions. The International Court of Justice is the principal judicial organ of the United Nations, which succeeded the Permanent Court of International Justice after WorldWar II. Article 92 of the charter of the United Nations states:The International Court of justice shall be the principal judicial organ of the United nations. It shall function in accordance with the annexed Statute, which is based upon the Statute of the Permanent court of International Justice and forms an integral part of The commands of internat ional law must be those that the states impose upon themselves, as states must give consent to thecommands that they will follow. It is a direct expression of raison detat, the interests of the state, and aims to serve the state, aswell as protect the state by giving its rights and duties. This is done through treaties and other consensual engagements which areThe case-law of the ICJ is an important aspect of the UNs contribution to the development of international law. Its judgementsand advisory opinions permeates into the international legal community not only through its decisions as such but through the widerimplications of its methodology and reasoning. The successful resolution of the border dispute between Burkina Faso and Mali in the 1986 Frontier Dispute case illustrates the utility of judicial decision as a means of settlement in territorial disputes. The case was submitted to a Chamber of the ICJpursuant to a special agreement concluded by the parties in 1983. In December 1985, while written submissions were being prepared, hostilities broke out in the disputed area. A cease-fire was agreed, and the Chamber directed the continued observance of the cease-fire, the withdrawal of troops within twenty days, and the avoidance of actions tending to aggravate the dispute or prejudice its eventual resolution. Both Presidents publicly welcomed the judgement and indicated their intention to comply with it. In the Fisheries Jurisdiction case (United Kingdom v. Iceland, 1974) the ICJ contributed to the firm establishment in law of the idea that mankind needs to conserve the living resources of the sea and must respect these resources. The Court observed:It is one of the advances in maritime international law, resulting from the intensification of fishing, that the former laissez-faire treatment of the living resources of the sea in the high seas has been replaced by a recognition of a duty to have due regard of the rights of other States and the needs of conservation for the benefit of all. Consequently, both parties have the obligation to keep inder review the fishery resources in the disputed waters and to examine together, in the light of scientific and other available information, the measures required for the conservation and development, and equitable exploitation, of these resources, taking into account any international agreement in force between them, such as the North-East Atla ntic Fisheries Convention of 24 January 1959, as well as such other agreements as may be reached in the matter in the The Court also held that the concept of preferential rights in fisheries is not static. This is not to say that the preferential rights of a coastal State in a special situation are a static concept, in the sense that the degree of the coastal States preference is to be considered as for ever at some given moment. On the contrary, the preferential rights are a function of the exceptional dependence of such a coastal State on the fisheries in adjacent waters and may, therefore, vary as the extent of that dependence changes. The Courts judgement on this case contributes to the development of the law of the sea by recognizing the concept of the preferential rights of a coastal state in the fisheries of the adjacent waters, particularly if that state is in a special situation with its population dependent on those fisheries. Moreover, the Court proceeds further to recogn ise that the law pertaining to fisheries must accept the primacy of the requirement of conservation based on scientific data. The exercise of preferential rights of the coastal state, as well as the hisoric rights of other states dependent on the same fishing grounds, have to be subject to the overriding consideration of proper conservation of the fishery resources for the benefit of all concerned. Some cases in which sanctions are threatened, however, see no actual implementation. The United States, for example, did not impose measures on those Latin American states that nationalized privately owned American property, despite legislation that authorizes the President to discontinue aid in the absence of adequate compensation. Enforcement measures are not the sole means of UN sanction. Skeptics of the coercive theory of international law note thatforceful sanctions through the United Nations are limited to situations involving threats to the peace, breaches of peace, and actsof aggressiion. In all other instances of noncompliance of international law, the charters own general provisions outlawing thethreat or use of force actually prevent forceful sanction. Those same skeptics regard this as an appropriate paradox in a decentralized state system of international politics. Nonetheless, other means of collective sanction through the UN involve diplomatic intervention and In 1967 the Security Council decided to isolate Southern Rhodesia (now Zimbabwe) for its policy of racial separation following its unilateral declaration of independence from Britain. As in other cases of economic sanctions, effectiveness in the Rhodesian situation was limited by the problems of achieving universal participation, and the res istance of national elites to external coercion. With respect to universal participation, even states usually sympathetic to Britains policy demonstrated weak compliance. Big Game EssayThe case-law of the ICJ is an important aspect of the UNs contribution to the development of international law. Its judgementsand advisory opinions permeates into the international legal community not only through its decisions as such but through the widerimplications of its methodology and reasoning. The successful resolution of the border dispute between Burkina Faso and Mali in the 1986 Frontier Dispute case illustrates the utility of judicial decision as a means of settlement in territorial disputes. The case was submitted to a Chamber of the ICJpursuant to a special agreement concluded by the parties in 1983. In December 1985, while written submissions were being prepared, hostilities broke out in the disputed area. A cease-fire was agreed, and the Chamber directed the continued observance of the cease-fire, the withdrawal of troops within twenty days, and the avoidance of actions tending to aggravate the dispute or prejudice its eventual resolution. Both Presidents publicly welcomed the judgement and indicated their intention to comply with it. In the Fisheries Jurisdiction case (United Kingdom v. Iceland, 1974) the ICJ contributed to the firm establishment in law of the idea that mankind needs to conserve the living resources of the sea and must respect these resources. The Court observed:It is one of the advances in maritime international law, resulting from the intensification of fishing, that the former laissez-faire treatment of the living resources of the sea in the high seas has been replaced by a recognition of a duty to have due regard of the rights of other States and the needs of conservation for the benefit of all. Consequently, both parties have the obligation to keep inder review the fishery resources in the disputed waters and to examine together, in the light of scientific and other available information, the measures required for the conservation and development, and equitable exploitation, of these resources, taking into account any international agreement in force between them, such as the North-East Atla ntic Fisheries Convention of 24 January 1959, as well as such other agreements as may be reached in the matter in the course of further negotiation. The Court also held that the concept of preferential rights in fisheries is not static. This is not to say that the preferential rights of a coastal State in a special situation are a static concept, in the sense that the degree of the coastal States preference is to be considered as for ever at some given moment. On the contrary, the preferential rights are a function of the exceptional dependence of such a coastal State on the fisheries in adjacent waters and may, therefore, vary as the extent of that dependence changes. The Courts judgement on this case contributes to the development of the law of the sea by recognizing the concept of the preferential rights of a coastal state in the fisheries of the adjacent waters, particularly if that state is in a special situation with its population dependent on those fisheries. Moreover, the Court proceeds further to recognise that the law pertaining to fisheries must accept the primacy of the requirement of conservation based on scientific data. The exercise of preferential rights of the coastal state, as well as the hisoric rights of other states dependent on the same fishing grounds, have to be subject to the overriding consideration of proper conservation of the fishery resources for the benefit of all concerned. Some cases in which sanctions are threatened, however, see no actual implementation. The United States, for example, did not impose measures on those Latin American states that nationalized privately owned American property, despite legislation that authorizes the President to discontinue aid in the absence of adequate compensation. Enforcement measures are not the sole means of UN sanction. Skeptics of the coercive theory of international law note thatforceful sanctions through the United Nations are limited to situations involving threats to the peace, breaches of peace, and actsof aggressiion. In all other instances of noncompliance of international law, the charters own general provisions outlawing thethreat or use of force actually prevent forceful sanction. Those same skeptics regard this as an appropriate paradox in a decentralized state system of international politics. Nonetheless, other means of collective sanction through the UN involve diplomatic intervention and economic sanctions. In 1967 the Security Council decided to isolate Southern Rhodesia (now Zimbabwe) for its policy of racial separation following its unilateral declaration of independence from Britain. As in other cases of economic sanctions, effectiveness in the Rhodesian situation was limited by the problems of achieving universal participation, and the resistance of national elites to external coercion. With respect to universal participation, even states usually sympathetic to Britains policy demonstrated weak compliance. The decentralization of sanctions remains one of the major weaknesses of international law. Although international bodiessometimes make decisions in the implementation of sanctions, member states must implement them. The states are the importers and exporters in the international system. They command industrial economies and the passage of goods across national boundaries. Furthermore, the UN is wholly dependent on its members on operating funds, so no matter what decisional authority its membersgive it, its ability to take action not only depends on its decision but also on means. Without the support, the wealth and the materialassistance of national governments, the UN is incapable of effective sanctions. The resistance of governments to a financially independent %0

Abraham Lincoln 10pg paper essays

Abraham Lincoln 10pg paper essays How has Abraham Lincoln impacted American history? Abraham Lincoln was an important part of American history. He ended slavery and helped America through the civil war. Abraham Lincoln was one of the truly great men of all time. Even as a boy, Lincoln showed ability as a speaker. He often amused himself and others by imitating some preacher or politician who had spoken in the area. People liked to gather at the general store in the crossroads village of Gentryville. Lincoln's gift for telling stories made him a favorite with the people there. In spite of his youth, he was well known in his neighborhood. In 1834, Lincoln again ran for the legislature. He had become better known by this time, and won election as a Whig. He served four successive two-year terms in the lower house of the Illinois General Assembly. During his first term, he met a young Democratic legislator, Stephen A. Douglas. Lincoln quickly came to the front in the legislature. He was witty and ready in debate. His skill in party management enabled him to become the Whig floor leader at the beginning of his second term. He took leading parts in the establishment of the Bank of Illinois and in the adoption of a plan for a system of railroads and canals. This plan broke down after the Panic of 1837. Lincoln also led a successful campaign for moving the state capital from Vandalia to Springfield. While in the legislature, Lincoln made his first public statement on slavery. In 1837, the legislature passed by an overwhelming majority resolutions condemning abolition societies. These societies urged freedom for slaves. Lincoln and another legislator, Dan Stone, filed a protest. They admitted that Congress had no power to interfere with slavery in the states where it existed. They believed "the promulgation of abolition doctrines tend rather to increase than abate its evils."*1 Their protest arose from the legislature's failure to call slavery an evi...

The Grim Reality of the United States Prison System essays

The Grim Reality of the United States Prison System essays The grim reality of the U.S. prison system We as Americans abide by rules imposed on society by past individuals, who believed that society could no longer function in a structured manner without such laws. These laws are what make freedom a reality; even so the price to pay for breaking a law that tarnishes the ultimate goal of society is a price most people, from a mental standpoint can barely survive. The harsh judgment man endures on judging another man is a punishment all in its self. Even so, this does not pertain to violent crime offenders, for nobody deserves to be attacked in such a manner. Regardless, non-violent crimes such as drug offenses need serious adjustment at the national and state level. There is substantially a significant amount of evidence to prove that the current punishment for non-violent criminals in no way contributes to excelling society to a higher intellect, but rather hinders the capabilities of society economically and morally. The American prison system is a system most people try to not thi nk about, why else would the system be in such a debacle as it stands today. Prison, the underworld that stretches deep into the dark depths of the soul, twisting and pulling ones mind into chaos; this wretched feeling is well deserved by violent crime offenders such as rapists, murderers, for they deserve no rights. From an Economic standpoint crime does pay for these individuals. Although non-violent crimes I woefully disagree with, the American prison system is to blame for the hindrance posed on these people; the public could benefit if 10-20 percent of prisoners were under some other form of rehabilitation rather than cold prison time. (Piehl, Dilulio, 20-5) The entire Economics of the prison system is as confusing as the laws written for people to get in there. The New Jersey prisoner self-report survey, show that the average violent crime prisoner costs, twenty five thousand dollars a year to impr...

The Grim Reality of the United States Prison System essays

The Grim Reality of the United States Prison System essays The grim reality of the U.S. prison system We as Americans abide by rules imposed on society by past individuals, who believed that society could no longer function in a structured manner without such laws. These laws are what make freedom a reality; even so the price to pay for breaking a law that tarnishes the ultimate goal of society is a price most people, from a mental standpoint can barely survive. The harsh judgment man endures on judging another man is a punishment all in its self. Even so, this does not pertain to violent crime offenders, for nobody deserves to be attacked in such a manner. Regardless, non-violent crimes such as drug offenses need serious adjustment at the national and state level. There is substantially a significant amount of evidence to prove that the current punishment for non-violent criminals in no way contributes to excelling society to a higher intellect, but rather hinders the capabilities of society economically and morally. The American prison system is a system most people try to not thi nk about, why else would the system be in such a debacle as it stands today. Prison, the underworld that stretches deep into the dark depths of the soul, twisting and pulling ones mind into chaos; this wretched feeling is well deserved by violent crime offenders such as rapists, murderers, for they deserve no rights. From an Economic standpoint crime does pay for these individuals. Although non-violent crimes I woefully disagree with, the American prison system is to blame for the hindrance posed on these people; the public could benefit if 10-20 percent of prisoners were under some other form of rehabilitation rather than cold prison time. (Piehl, Dilulio, 20-5) The entire Economics of the prison system is as confusing as the laws written for people to get in there. The New Jersey prisoner self-report survey, show that the average violent crime prisoner costs, twenty five thousand dollars a year to impr...

Personal statement for university explaing why did I choose that

For university explaing why did I choose that university and course - Personal Statement Example pecialize in databases and data mining, because I am really interested in learning about how large datasets and huge chunks of information can be stored in and managed so quickly and efficiently. I would love to learn about new advancements in this field, and would like to become a talented professional in my future life. For me, computer science has changed the world like no other science. Why I chose the University of New Haven, Boston Post Road West Haven, is because it offered me graduation in computer science which I wanted to avail and start my career in. The university is a private, top-tier institution, and offers globally recognized experiential education. It offers highly qualified teachers. It helps the students in various means like in getting a tutor, scholarships, free-ships, stipends, internships, and etcetera. Special training courses are also held which enable the students to apply the knowledge

Successful Conflict Resolution for Divorced Couples Essay

Successful Conflict Resolution for Divorced Couples - Essay Example At other times, people appear to have rushed into a marriage without properly understanding each other and knowing all the aspects of their spouse's personality. In such a scenario, marriage turns out to be a shock when one comes across the true nature of one's life partner. There is no dearth of cases when the couples tend to have different relational expectations and thus end up having a divorce. However, once a divorce is finalized, the problem does not end here only. The post divorce scenario gives ways to a plethora of conflicts and issues between the couples. The divorce process in itself tends to be a very stressful and trying situation for the involved couples. The entire procedures involves settling and deciding upon a whole range of vital issues like splitting the finances and assets, deciding as to whether the couple intends to go fore a divorce by mutual consent or intends to contest, and above all parenting and kids. Unless both the parties tend to cooperate and resolve their disputes with ample patience and caution, the divorce procedure and the post divorce situation could end up getting real nasty and miserable (Sherman, 2000). Under such circumstances, apt and effective interpersonal communication could play a pivotal role in a successful conflict resolution between the divorced couples. Interpersonal Interpersonal communication stands to be the interactive process that takes place between the two people and this interaction may tend to be face-to-face or may perhaps be mediated by a third party. Apt and conducive interpersonal communications not only plays a central role in most of the successful marriages, but it could also go a long way in settling disputes between the aggrieved couples in a post divorce scenario. Still, the irony is that in most of the divorces, shoddy interpersonal communication tends to be one of the, if not the sole responsible factor. Therefore, how can one expect the divorced couples to negotiate amicably in a post divorce scenarioDivorce can be really less painful if the divorced couples tend to be cognizant of some fundamentals of interpersonal communication. The basic thing to be understood by the divorced spouses is that they simply cannot escape the requisite interpersonal communication, even if they are divorced (King, 2000). Hence, a willingness to communicate tactfully with one's ex could go a long way in settling the post divorce issues, reasonably and amicably. The second thing that the divorced couples must accept is that interpersonal communication is always complex, especially in a divorce scenario (King, 2000). In addition, interpersonal communication always happens to be irreversible (King, 2000). One simply cannot rescind a message, once it is conveyed. Therefore, communication between divorced couples requires patience and a capacity to listen to each other. Above all, interpersonal communications always takes place in a context and never happens in

Small and Medium Enterprises Coursework Example | Topics and Well Written Essays - 10000 words

Small and Medium Enterprises - Coursework Example It has been found that over the past several years throughout the industrialized countries the extra growth that has been achieved is due to the large growth in SMEs (Barakat, 2001). SMEs constitute the dominant form of business organization, accounting for over 95% and up to 99% of enterprises depending on the country. They are responsible for between 60-70% net job creation in OECD countries. Small businesses are particularly important for bringing innovative products or techniques to the market (OECD, 2006). SMEs in any country can grow by partnerships between the private and the public sector by provision of high quality business support that includes training for the development and improvement of the managerial skills for potential and currently operating SMEs. Furthermore, government can assess SMEs in selling their products and services domestically as well as on international front. But most important factor is the financial support. Availability of capital and credit is considered as a major stimulant for the development of the SMEs in many industrialized nations and specially the developing world. Besides government larger and bigger businesses and corporations operating in an economy can help SMEs become more viable business partners by providing training in basic skills such as management, bookkeeping, business planning, marketing, distribution, and quality control. They can assist through technology transfers, direct investment in infrastructure, and the sharing of knowledge. This will make SMEs more competitive and facilitates access to credit. SMEs as their start up financing and also operations and working capital needs require greater access to financial services and investment capital. Unlike SMEs big businesses have little difficulty in securing sizeable bank loans and private investments. At the same time, microfinance, consisting of very small loans, tends to benefit individual entrepreneurs. SMEs fall in between and often struggle to obtain credit and loans. Some 90% of entrepreneurs in Latin America are obliged to source much of their financing from personal savings according to Inter-American Development Bank (IDB) estimates, a picture true throughout much of the developing world (World Business Council for sustainable development). Many financial institutions in the developed and the developing world are reluctant to fund SMEs because of perceived risk and high transaction costs.16 SMEs in the developing world are considered high-risk, as their managers are perceived as lacking managerial expertise, credit history, and/or tangible assets to secure loans. Thus loans to SMEs, when they are able to obtain them, tend to carry higher interest rates and shorter pay-back times. Definition of an SME There is not a single characteristic that is used to define an SME; and thus there is no single definition of SME that can be used as a standard for businesses to qualify as and SME or a large business. Some economists, governments and analysts define SMEs in terms of their revenue generation capabilities, others see how many people have been employed, more criteria consider the land that is occupied for business operations. European Union's indication for a small business is one with a headcount of less than 50 and a microenterprise as one with a maximum of 10 employees; whereas

Development of CT Scans for Cancer Studies

Development of CT Scans for Cancer Studies According to the statistics presented by the World Health Organization (WHO), with around 7.4 million deaths (around 13% of the total death) in 2004, cancer is the leading cause of death throughout the world (WHO, 2009). These levels are expected to rise further in future, with an estimated 12 million death in 2030 (WHO, 2009). There are more than 100 different types of cancer (Crosta, n.d.), among them the Lung cancer, stomach cancer, colorectal cancer, liver cancer and the breast cancer are the most common types. Tobacco is the most important risk factor for cancer, with nearly 1.3 million deaths per year just due to lung cancer alone (WHO, 2009). Cancer At the primary level, human body consists of large number building blocks, called the cells. Under normal circumstances, new cells are formed by the body depending on the body requirement, in order to replace the dead cells. But sometimes, under abnormal conditions, there is an exponential (uncontrolled) increase in the formation and growth of new cells. The accumulation of these extra cells forms mass or lumps of tissues, called the tumor (National Cancer Institute, 2010). Most of the cancers, in general form tumors, but there are certain exceptions, like leukemia, that do not form tumors (in leukemia or blood cancer, the cancer cells hinder the normal blood functions due to abnormal cell disintegration in the blood stream (Crosta, n.d.)). The tumors can be of two types; benign tumor and malignant tumor. The benign tumors do not propagate to other sections of the body and have restrained growth (Crosta, n.d.), whereas the malignant tumor cells have the ability to invade into the sur rounding tissues. Also the malignant tumor cells can escape from their initial location and spread to other sections of the body through blood or lymph. Only the malignant tumors are cancerous in nature. Therefore, the cancer has three distinctive properties that distinguish malignant tumors from benign tumors: Uncontrolled growth Invasive nature Metastasis (ability to spread to other sections of the body) These disorders in cells are the result of the interaction between the genetic factors and external agents (which are called carcinogens) (WHO, 2009). The carcinogens can be categorized as (WHO, 2009): Biological carcinogens, like certain bacteria, viruses or parasites. Physical carcinogens, which includes the high energy radiations (ionizing radiations). Chemical carcinogens, these include substances like tobacco smoke, arsenic (water contaminant), aflatoxin (food contaminant), asbestos etc. Another factor essential in the development of cancer is the age. According to the studies conducted by the Cancer Research UK, the risk increase predominantly with increasing age, with nearly 74% of the cases of cancer diagnosed in people aged 60 and above (Cancer Research UK, 2009). Cancer Treatment Principle In case of normal cells there is specific pattern of growth, division and death (orderly destruction of cells is called apoptosis) (Crosta, n.d.). It is known that the cancer is the result of the uncontrolled growth of cells which do not die (Crosta, n.d.), that is, the apoptosis process fails in the cancer cells. The cancer cells thus do not die and rather continue to grow, resulting in the formation of tumors. As the problem in the cancer cells lies in the DNA, therefore a possible treatment of cancer is the destruction of the DNA in cancer cells, leading to a self initiated destruction of the cells. There are various methods used for the treatment of cancer depending upon the type of cancer. The most common types of treatment are (Fayed, 2009): Surgery Chemotherapy Radiation therapy or Radiotherapy Biologic or Targeted Therapy Radiotherapy Radiotherapy, also referred to as radiation therapy, is one of the most common types of treatments used for cancer. It is the utilization of higher energy radiations like x-rays, gamma rays in order to kill cancer cells, treatment of thyroid disorder and even some blood disorders, in a particular section (effected part) of the body (Nordqvist, 2009). The high energy ionizing radiations can be produced using a number of radioactive substrates like Cobalt (60Co), Radium (228Ra), Iodine (131I), Radon (221Rn), Cesium (137Cs), Phosphorus (32P), Gold (198Au), Iridium (192Ir), and Yttrium (90Y) (Howington, 2006). The cancer cells have the ability to multiply faster than other body cells. The high energy ionizing radiations are more destructive towards the faster growing cells, and thus they damage the cancer cell more than the other body cells (Mason, 2008). These high energy radiations like gamma rays and x-rays; especially damage the DNA inside these cancer cells (or tumor cells) thereby annihilating the ability of the cells to reproduce or grow. Apart from treatment of cancer, radiation therapy is also used to shrink a tumor before being surgically removed (Mason, 2008). Depending upon the method of irradiation, the process of radiation therapy is categorized into two forms (Mason, 2008): External Radiotherapy In this method (more common), the infected part of the body (tumor) is irradiated by high energy x-rays from outside the body. Internal Radiotherapy For this method, a radioactive substance are injected (or taken orally) into the body (close to the tumor) in the form of fluids. These substances, taken up by the cancer cells, radiate the tumor through internal beam radiation (or interstitial radiation) (Mason, 2008). Radiotherapy Planning A careful planning is essentially required for radiation therapy, as over exposure can be critically dangerous to healthy tissues in the body. The ionizing radiations have side effects, therefore once the full dose of radiations is decided; the patient is given these radiations in the form of small doses in a series of therapy sessions (Cancer Research UK, 2009). Each small dose of radiation is called a fraction. The gap between sessions provides the recovery time for the body, which may depend on the type of cancer and patients health condition. The area of the body that is radiated during the treatment is called the radiotherapy field and the section inside the body that experiences the maximum exposure dose is called the target volume (Cancer Research UK, 2009). The doctors decide the marginal area around the tumor that should be radiated to encapsulate any movement of the cancer cells. In order to accurately determine the position of tumor (or target volume), body scans are done. Computed Tomography (CT) scans are done as a planning procedure, this provides vital information regarding the location of the tumor as well as the kind of treatment required by the patient (Cancer Research UK, 2009). The radiotherapy treatment planning process can be divided into 6 major steps . Computer Tomography (CT) Scan The invention of Computer Tomography (CT) scanned is credited to Sir Godfrey Hounsfield in early 1970s, for which he along with Allen Cormack, was awarded the Nobel Prize in 1979 (Smith, n.d.). A CT scanner, also known as the Computed Axial Tomography (CAT) scanner uses X-rays to produce cross sectional images (or slices) of the body like a slice in a loaf of bread (FDA, 2010). The word tomography suggests the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram) (Nordqvist, 2009). These cross-sectional slides render an accurate picture of the size and location of the tumor along with the position of major organs in the body (Cancer Research UK, 2009). This would be essentially useful during the radiotherapy process, where these can be used to lower the dose of radiations on the organs. It is known that in case of radiation therapy treatment, the doses are given in fractions over a certain period of time (to prevent major side effects), which may vary from few weeks to months. Thus, before each fraction of radiation dose, computed tomography (CT) scan of the patients is done to determine the exact location of the tumor or cancer cells. So in case the full dose has been divided into 30 fractions, then the patient has to undergo 30 CT scans, each before a fractional therapy. The machine used for the radiation therapy planning is known as the simulator (Cancer Research UK, 2009). The simulator identifies the position of the tumor and marks the position of radiation on the body with the help of light rays. The radiographer uses ink markers on the body before the actual radiotherapy is begun. These linear ink marks are used by the radiographer for positioning the machine for radiotherapy (Cancer Research UK, 2009). Simulators take the pictures (CT scans) in the form of X-rays, which locates the accurate tumor position for the radiographer to carry out the treatment. During a CT scan, it is essential that the person remains completely still so that the measurements are accurate. In order to insure the correct position supports like neck rest, chest board or arm pole are used (Cancer Research UK, 2009). In case of children it is ensured by giving proper sedatives. Sometimes, under critical condition, extra measures are taken in order to prevent essential organs from being radiated during the therapy. These measures include injecting fluids or dyes which mark the position of vital human organs in the CT scan (Cancer Research UK, 2009). These markers may be given orally, through injections or rectally depending upon the requirement. Using this vital information from the CT scans, a treatment plan for radiation therapy is prepared. This plan indicates the position and direction of the radiations during the therapy, so as to minimize the exposure of healthy cells and organs. The scans generated by a CT scanner are in the form of 2 dimensional (2-D) slides, but by the used of digital geometry processing they can be used to generate a 3 dimensional (3-D) images of the body (Nordqvist, 2009). This can be achieved by integrating all the slides (along the same axis) together using a computer system. The CT scan can be understood as a technically advanced format of X-rays machines. The x-rays images are produced by the projection of a broad beam of x-rays on a film after passing through the body (Medindia, 2010). It provides a 2-dimentional projection of the body, where much of the information is lost. In case of CT scan, a thin beam of x-rays is absorbed by the detector after passing though the patients body (Medindia, 2010). Like the x-ray process, the CT scanning is a painless process for the patients but has been known to be accompanied with some side effects. These side effects may vary from the patient to patient depending upon the amount of radiation dose and health of the patient. The detailed discussion on the health effects of CT scanning has been discussed in the later sections of the project. Theory In order to understand the working of a computed tomography (CT) scanner it is essential to understand the properties of ionizing radiations (X-rays) used in the scanning process. The electromagnetic radiations are the arrangement of electric-field and magnetic-field vectors perpendicular to each other and also perpendicular to the propagation direction of the wave (Resnick et al., 2009). These Electromagnetic radiations have penetrating powers, which are directly dependent on the energy (or frequency) of these radiations. So that radiations with higher frequency have higher penetration powers. Therefore, on the basic the energy, the electromagnetic radiations are categorized as Non-ionizing radiations and Ionizing radiations. Non-Ionizing radiations refer to the electromagnetic radiations which have energy lower than that required for an atomic ionization (MIT, 2001). The non-ionizing radiations include radio waves, micro waves, visible light etc. These radiations have lower penetration powers. Alternatively the Ionizing radiations are the high frequency radiations which have enough energy to knockout an electron from an atom and thus causing ionization (MIT, 2001). The Gamma rays and X-rays are the common type of ionizing radiations. Even the alpha particles and beta particles emitted in a nuclear reaction are ionizing radiations (MIT, 2001). Due to the higher energy they have higher penetration power than the non-ionizing radiations. Principle of CT Scanning The most important section of a Computed Tomography (CT) scanning is the interaction of the ionizing X-ray radiations with the living tissues in the body. When the ionizing radiations (X-rays) interact with the living tissues in the body, they break up atoms and molecules from the living tissues and disrupt chemical reactions within the body (Zamanian Hardiman, 2005). The intensity of absorption of the x-ray radiations by the body varies depending upon the tissue coming in interaction. Different body tissues have different absorption power, where some are permeable to x-rays others are impermeable (Medindia, 2010). It is due to this difference in the absorption ability of different sections of the body, which results in the generation of a graded pattern in the scans. High density tissues like the bones appear white in the scan while the soft tissues (like brain and kidneys) appear dark. The cavities (like the lungs) are seen as black sections in the scan (Medindia, 2010). Therefore, this gradation in the pattern can be used as method to distinguish different body organs depending upon their absorption capacity. This forms the basic principle behind the working of an X-ray scanning. Radon (1917) was the first to develop the principles of computed tomography (CT) mathematically (Bushberg et al., 2002). According to Radon, with the help of infinite number of projections through an object, it could be possible to produce an image of an unknown object. In case of film imaging (as in conventional X-rays), a two-dimensional (2-D) projection of the body is generated on the film. Due to this, details in the dimension of the body along the direction parallel to the x-ray beam are lost. In order to overcome this drawback (only up to a certain level) projections can be taken along two directions; posteroanterior (PA) projection and lateral projection (Bushberg et al., 2002) (as shown in Figure 4). Increasing the number of scans improves the amount of information but in critical and complex cases where much more details are required. For these critical cases, CT scan is done. The CT scan provides the tomographical image, which is the picture of patients body in the sections or slabs. The thickness of these uniform slabs may vary from 1 millimeter to 10 millimeter (Bushberg et al., 2002), according to the program, depending upon the requirement. Each CT image consists of an array of large number of pixels forming a two dimensional (2-D) image, which corresponds to the same number of three dimensional thin rectangular slabs called the voxel. The voxels are the volume element whereas the pixels are the picture element (Bushberg et al., 2002). Every ray from the X-ray source passes (transmits) through the patient before the transmission measurement is done by the detector. Intensity of the un-attenuated x-ray radiation emitted by the source is Io whereas the intensity of the attenuated radiation after transmitting through the patient is given as It. The intensities Io and It are related by the equation (Bushberg et al., 2002):   Ã‚  Ã‚  Ã‚  Ã‚  It=Ioe-ÃŽ ¼t   Ã‚  Where;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚ µ is the total linear attenuation coefficient of the tissue (Smith, n.d.).   Ã‚  Ã‚  Ã‚  Ã‚  t is the distance travelled by the radiation in the tissue i.e. the tissue thickness. The coefficient  µ is dependent on the atomic number and electron density of the tissues (Smith, n.d.). Higher the atomic number and electron density of the tissues, higher would be the attenuation coefficient (Smith, n.d.). This form the basic principle of CT scanning, that different tissues have different level of attenuation properties depending upon their atomic number and electron density. For every measurement, the overall attenuation coefficient is calculated using the above equation. During a complete 360o ­ scan, various transmission measurements for the intensity of X-ray photon are done. Using these intensity measurements specific attenuation values are allotted to every voxel (volume element). These attenuation numbers are directly proportional to the linear attenuation coefficient. The average of these attenuation values is called the CT number (Smith, n.d.). These values can be arranged on a linear scale, the units of which are called the Hounsfield units (HU). The scale for modern CT scanners varies from approximately -1,000 to 3,000 HU. The attenuation scale is based on binary system and therefore the exact values range from -1,024 to +3,071, with a total of 4,096 (or 212) attenuation numbers. Here, the lower represent the black section while the higher values represent the white section of the CT image. On this scale the attenuation value of water is zero HU and that of air is -1,000 HU (Smith, n.d.). Both of these values act as the reference points. Construction of a CT scanner CT scanner is a complex machine, but the basic structure is simple. A common CT scanner has been shown in Figure 2. Two most important parts of a CT scanner are the X-ray source and detector. The source and detector are placed in a circular structure, which has a shape similar to a doughnut. This doughnut shaped circular opening is called the gantry (RadiologyInfo, 2009), with an inner (opening) diameter varying from 60 cms to 70 cms. The X-ray source and detector are placed exactly (diagonally) opposite each other, so that the radiations emitted by the source pass through the body and the transmitted radiations are measured by the detector. The x-ray source and detector system in the gantry is motorized to rotate around the patient for measurements in different projection angles. The rational speed of the system is adjusted according to the detectors ability to measure and convert the x-ray beam into electronic signal. Cobalt (60Co) is generally used as the source of x-rays in the CT scanners. The detector used in CT scanner consists of an array of detectors in a slightly curved shape (like a banana). This curved shape is especially useful in fan-shaped beam projects. Two types of detectors are generally utilized in the CT scans; solid state or scintillation detector and Xenon gas detector (Reddinger, 1997). But the solid state detectors with scintillators like Cadmium Tungstate (CdWO4), yttrium, gadolinium ceramics etc are commonly used (Bushberg et al., 2002). The principle of the scintillation detector is that, when it is struck by a x-ray photon, it produces light. This light signal is then transformed to electrical signal with the help of photodiode. The Depending upon their structure, the detectors are categorized into two categories; single detector array and multiple detector array. Another essential part of a CT scanner is the motorized examination table. The table is controlled to move in and out of the gantry during the scanning process. As the position of the x-ray source and detector is fixed therefore the section being scanned is controlled by the movement of the examination table. For a better scan it is necessary that the patient remains completely still. To insure this table is equipped with neck rest, chest board and arm pole (Cancer Research UK, 2009). The detector measures the intensity of the radiation and converts them into electrical signals. These raw signals are analyzed and manipulated by the computer to convert them into images which can be understood by the radiologists and the technicians. Multiple computers are required in a CT scanner. The main computer that controls the operation of the entire system is called the host computer (Imaginis, n.d.). The computers and controls are located in a room adjoining the scanning room. This prevents the technicians and the radiographer from exposure to x-rays. Scanning Procedure in a CT scanner Initially the patient is positioned on the examination (or scanning) table in a flat upright posture (face towards the roof). In order to insure the correct and stationary position, straps and pillows may be used along the body. Once the patient is correctly positioned on the scanning table, the motorized table moves the patient into the circular opening of the CT scanner (FDA, 2010), which the x-ray radiations are projected on the patient from the scanning. For a particular position of the x-ray source and detector, the rays from the source pass through a region called the projection or view. There are two different types of projection geometries that are used in CT scanning; parallel beam geometry and fan beam geometry. In the parallel beam geometry, the rays projected on the patient are parallel to each other whereas in fan beam geometry, the rays diverge from the source in the shape of a fan (Bushberg et al., 2002) as shown in Figure 7. The fan beam projections are the most commonly in used x-ray projections in the CT scanners. The X-ray tube is attached with a collimator which controls the thickness of the fan beam. This thickness (of the fan beam projection) determines the width of the tissue slide in the scanning process. It is through the collimator that the slice thickness is varied between 1mm to 10mm (Smith, n.d.). The x-ray source and detector rotate around the patient (for imaging) in a circular motion such that they always remain exactly (diametrically) opposite to each other (as shown in Figure 7). During the rotation the source keeps emitting x-rays which are attenuated after passing through the patient. For a single projection (or slice), the x-ray source and detector make a complete 360o rotation around the patient. During the rotation the detector takes a large number of snapshots of the absorbed X-ray beam at different projection angles. A single image may involve approximately 800 rays and there can be up to 1,000 different projection angles (Bushberg et al., 2002). Therefore for a single projection (one slice), the detector does nearly 800,000 transmission measurements (Bushberg et al., 2002). The scanning of a single projection generally takes around 1 sec (for axial CT scanners) (FDA, 2010). Once all the transmission measurements (complete 360o) for a projection (or slice) are completed, the motorized table moves along the axis of the gantry so that the next slice of tissues forms the projection view. The process is continued till the complete required section of the body has been scanned. In the traditional CT scanners, the table moved on to the next projection (slice) only when the scanning of the previous was completed. Such conventional type of scanning is called the axial scanning. But in modern CT scanners, called the helical or spiral CT scanners, the rotation of the x-ray source and detector is accompanied with the uniform movement of the examination table, thus producing a helical projection. The helical CT scanning has been shown in Figure 9. These modern helical CT scanners are much faster than the traditional scanners due to continuous scanning process. They have been reported to take nearly half the time for scanning as compared to the traditional CT scanner s. In order to analyze and study the cardiac structure which is under constant motion, even helical CT is ineffective. For such applications a special CT scanner with an exposure time of 50ms and a maximum exposure rate of 17 images per second are used (Smith, n.d.). These scanners, called the cine CT, freeze the cardiac motion due to extremely low exposure time resulting in a sharp image (Smith, n.d.). These scanners use electron beam to generate x-rays, thus are also known as Electron Beam Computed Tomography (EBCT). In the CT scanning process large volume of data and operations are required to be processed, which is achieved with the help of multiple computers. The detector converts the intensity measurements of the attenuated x-rays in to electrical signals. The main computer, called the hub computer processes these signals and converts them into an image. These images can then be analyzed for radiotherapy planning. Result Computed Tomography (CT) has become an invaluable medical tool. It provides detailed 3-D images of various sections of the body like pelvis, soft tissues, lungs brain, blood vessels and bones (Nordqvist, 2009). Generally, CT scanning is the preferred method of diagnosing different types of cancers like liver, lungs and pancreatic cancers (Nordqvist, 2009). The tomographic images produced by the CT scan provide specific location and size of the tumor along with the details of affected tissues in the proximity of the tumor. This is especially advantageous in planning, guiding, and monitoring therapies like radiotherapy (FDA, 2010). CT scanning has various benefits over other traditional diagnostic techniques; some of the benefits are (RadiologyInfo, 2009): It is non-invasive, painless and extremely accurate. A major advantage is the ability to identify and distinguish bones, soft tissues and blood vessels in the same image. It also provides real time images which cannot be done in conventional X-rays. This technique is fast and simple; and is extensively used to locate internal injuries after accidents. It is less sensitive towards patient movement as compared to MRI. CT scanning can be used on patients with medical implants unlike the MRI. For an effective radiation therapy treatment, it is necessary that only the tumor is irradiated while minimum damage occurs to the surrounding health (normal) body tissues (Badcock, 1982). This is achieved with the help of CT imaging technique. In a study by Badcock (1982), 186 patients with various malignancies were studied and it was found that in nearly 39% of the treatment cases CT scanning was valuable in the assessment of the radiationdose calculation (Badcock, 1982). According to his study, CT scanner resulted in an alternation in target dose by more than 5%, (as compared to the traditional methods) in 27% of the patients (Badcock, 1982). The result has been shown in the table below. The mean alternation was 6.5% of the target dose and usually resulted in reduction of dose per fraction by factors upto 35% (Badcock, 1982). Even with these advantages, the adverse affect of the ionizing x-ray radiations cannot be neglected. Various experiments and researches have consolidated the fact that ionizing radiations like x-rays, gamma rays etc have adverse effect on living tissues. Zamanian Hardiman (2005) have explained that when high energy ionizing radiations interact with living tissues they strip-off atoms and molecules from them. This disrupts the chemical reaction within the body and failure in organ functioning (Zamanian Hardiman, 2005). The adverse effects of ionizing radiations were seen shortly after its discovery in 1890s, with a scientist involved in the study of radioactivity were reported with skin cancer in 1902. But is was not until 1944, that the role of radiations in causing leukemia in human was first documented, mainly in radiologists and physicists (Zamanian Hardiman, 2005). In recent years the use of x-rays has extensviely increased in medical field for diagonostic and treatment application. According to the U.S. Environmental Protection Agency, X-ray deveices are the largest source of man-made radiation exposure (US_EPA, 2007). According to NCRP Report No. 160 (2006), the average annual effective dose per individual in the US population, from all sources has increase from 1.7mSv in 1980s to 6.2mSv in 2006. This increase is mainly attributed to the striking growth of high dose medical imaging procedures that utilize x-rays and radionuclides (NCRP, 2008). Such man-made devices include X-ray machines, CT scans etc. CT scans, especially result in high dose x-ray exposure, with nealy 100 times the exposure dose as compared to standard x-ray equipments (Coach, 2008). Some of the major risks associated with CT scanning are: It is well documented that ionizing radiaitons like x-rays have the ability to cause cancer on exposure. Therefore, the CT dose in radiotherapy increase the probabilty of cancer in the future. Even though only 4% of the total x-ray examinations are CT scans, they account for more than 20% of the radiation dose to the population by medical x-rays (King Saud University, 2004). In general, the effective dose in a CT scan procedure ranges from 2 mSv to 10mSv, which is nearly equivalent to the amount of radiation that a person receive from the background exposures in three to five years (RadiologyInfo, 2009). A CT scan during preganacy make cause serious illness or even birth defects in the unborn baby (FDA, 2010). Children are more sensitive and vulnerable to x-ray exposures than the adults, therefore their CT scanning should be done only under extremely essential and necessary conditions. Women have higher risk of developing cancer in the lifetime, as compared to men under same levels of exposure (FDA, 2009). In some rare situation of high-dose prolonged radiation exposure, the x-rays can cause adverse effects like skin reddening (erythema), skin tissue injury, hair loss, cataracts etc (FDA, 2010). In a study, Sawyer et al (2009) estimated the effective dose resulting from a cone beam CT scanning for planning of radiation therapy using thermoluminescent dosemeters (TLDs) for organ dose and using International Commission on Radiological Protection (ICRP) 60 tissue weighing factor (Sawyer et al., 2009). The results obtained for effective dose from TLD measurements and ICRP 60 weighting factor, for breast, pelvis and head simulation have been shown in the table below. The scanning process results in the exposure of the normal tissues outside the treatment volume (Waddington McKenzie, 2004). It is thus important to analyze the effect that the irradiation caused by the CT scanning process has on the patients body. In a study, Waddington McKenzie (2004) analyzed the propability of developing cancer from the irradiations caused by the extended field portal imaging techniques, the results of which are given in the table below (Waddington McKenzie, 2004). In order to illustrate a real life situation, the calulations in the study were done for an average man with a height of 170 cms and weight of 70 kgs (Waddington McKenzie, 2004). Therefore, these values may change depending upon the height, weight and tumor size of the patient. Discussion Various studies have been done to statistically evaluate the effect of the ionizing radiations on the human health. These risks have severely amplified due to the rapid increase in the number of CT scans for diagnostic applications. CT scans form nearly 5% of all procedures used in diagnostic radiology in the developed countries (Wrixon et al., 2004). In U.S., nearly 70 million CT scans were done in 2007 as compared to just 3 million done in 1980 (Steenhuysen, 2009), this includes more than 4 million children in 2006 (Brenner Hall, 2007). Thus, according to the NCRP Report no. 160, the average radiation dose per person has increased from 3.6 mSv in early 1980s to 6.2 mSv in 2006 (NCRP, 2008). Steenhuysen (2009) has reported that the radiations from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 people in America (Steenhuysen, 2009). These stats explain the level of exposure caused by the CT scans. According to estimates by Amy Berrington de Gonzalez of the National Cancer Institute, Development of CT Scans for Cancer Studies Development of CT Scans for Cancer Studies According to the statistics presented by the World Health Organization (WHO), with around 7.4 million deaths (around 13% of the total death) in 2004, cancer is the leading cause of death throughout the world (WHO, 2009). These levels are expected to rise further in future, with an estimated 12 million death in 2030 (WHO, 2009). There are more than 100 different types of cancer (Crosta, n.d.), among them the Lung cancer, stomach cancer, colorectal cancer, liver cancer and the breast cancer are the most common types. Tobacco is the most important risk factor for cancer, with nearly 1.3 million deaths per year just due to lung cancer alone (WHO, 2009). Cancer At the primary level, human body consists of large number building blocks, called the cells. Under normal circumstances, new cells are formed by the body depending on the body requirement, in order to replace the dead cells. But sometimes, under abnormal conditions, there is an exponential (uncontrolled) increase in the formation and growth of new cells. The accumulation of these extra cells forms mass or lumps of tissues, called the tumor (National Cancer Institute, 2010). Most of the cancers, in general form tumors, but there are certain exceptions, like leukemia, that do not form tumors (in leukemia or blood cancer, the cancer cells hinder the normal blood functions due to abnormal cell disintegration in the blood stream (Crosta, n.d.)). The tumors can be of two types; benign tumor and malignant tumor. The benign tumors do not propagate to other sections of the body and have restrained growth (Crosta, n.d.), whereas the malignant tumor cells have the ability to invade into the sur rounding tissues. Also the malignant tumor cells can escape from their initial location and spread to other sections of the body through blood or lymph. Only the malignant tumors are cancerous in nature. Therefore, the cancer has three distinctive properties that distinguish malignant tumors from benign tumors: Uncontrolled growth Invasive nature Metastasis (ability to spread to other sections of the body) These disorders in cells are the result of the interaction between the genetic factors and external agents (which are called carcinogens) (WHO, 2009). The carcinogens can be categorized as (WHO, 2009): Biological carcinogens, like certain bacteria, viruses or parasites. Physical carcinogens, which includes the high energy radiations (ionizing radiations). Chemical carcinogens, these include substances like tobacco smoke, arsenic (water contaminant), aflatoxin (food contaminant), asbestos etc. Another factor essential in the development of cancer is the age. According to the studies conducted by the Cancer Research UK, the risk increase predominantly with increasing age, with nearly 74% of the cases of cancer diagnosed in people aged 60 and above (Cancer Research UK, 2009). Cancer Treatment Principle In case of normal cells there is specific pattern of growth, division and death (orderly destruction of cells is called apoptosis) (Crosta, n.d.). It is known that the cancer is the result of the uncontrolled growth of cells which do not die (Crosta, n.d.), that is, the apoptosis process fails in the cancer cells. The cancer cells thus do not die and rather continue to grow, resulting in the formation of tumors. As the problem in the cancer cells lies in the DNA, therefore a possible treatment of cancer is the destruction of the DNA in cancer cells, leading to a self initiated destruction of the cells. There are various methods used for the treatment of cancer depending upon the type of cancer. The most common types of treatment are (Fayed, 2009): Surgery Chemotherapy Radiation therapy or Radiotherapy Biologic or Targeted Therapy Radiotherapy Radiotherapy, also referred to as radiation therapy, is one of the most common types of treatments used for cancer. It is the utilization of higher energy radiations like x-rays, gamma rays in order to kill cancer cells, treatment of thyroid disorder and even some blood disorders, in a particular section (effected part) of the body (Nordqvist, 2009). The high energy ionizing radiations can be produced using a number of radioactive substrates like Cobalt (60Co), Radium (228Ra), Iodine (131I), Radon (221Rn), Cesium (137Cs), Phosphorus (32P), Gold (198Au), Iridium (192Ir), and Yttrium (90Y) (Howington, 2006). The cancer cells have the ability to multiply faster than other body cells. The high energy ionizing radiations are more destructive towards the faster growing cells, and thus they damage the cancer cell more than the other body cells (Mason, 2008). These high energy radiations like gamma rays and x-rays; especially damage the DNA inside these cancer cells (or tumor cells) thereby annihilating the ability of the cells to reproduce or grow. Apart from treatment of cancer, radiation therapy is also used to shrink a tumor before being surgically removed (Mason, 2008). Depending upon the method of irradiation, the process of radiation therapy is categorized into two forms (Mason, 2008): External Radiotherapy In this method (more common), the infected part of the body (tumor) is irradiated by high energy x-rays from outside the body. Internal Radiotherapy For this method, a radioactive substance are injected (or taken orally) into the body (close to the tumor) in the form of fluids. These substances, taken up by the cancer cells, radiate the tumor through internal beam radiation (or interstitial radiation) (Mason, 2008). Radiotherapy Planning A careful planning is essentially required for radiation therapy, as over exposure can be critically dangerous to healthy tissues in the body. The ionizing radiations have side effects, therefore once the full dose of radiations is decided; the patient is given these radiations in the form of small doses in a series of therapy sessions (Cancer Research UK, 2009). Each small dose of radiation is called a fraction. The gap between sessions provides the recovery time for the body, which may depend on the type of cancer and patients health condition. The area of the body that is radiated during the treatment is called the radiotherapy field and the section inside the body that experiences the maximum exposure dose is called the target volume (Cancer Research UK, 2009). The doctors decide the marginal area around the tumor that should be radiated to encapsulate any movement of the cancer cells. In order to accurately determine the position of tumor (or target volume), body scans are done. Computed Tomography (CT) scans are done as a planning procedure, this provides vital information regarding the location of the tumor as well as the kind of treatment required by the patient (Cancer Research UK, 2009). The radiotherapy treatment planning process can be divided into 6 major steps . Computer Tomography (CT) Scan The invention of Computer Tomography (CT) scanned is credited to Sir Godfrey Hounsfield in early 1970s, for which he along with Allen Cormack, was awarded the Nobel Prize in 1979 (Smith, n.d.). A CT scanner, also known as the Computed Axial Tomography (CAT) scanner uses X-rays to produce cross sectional images (or slices) of the body like a slice in a loaf of bread (FDA, 2010). The word tomography suggests the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram) (Nordqvist, 2009). These cross-sectional slides render an accurate picture of the size and location of the tumor along with the position of major organs in the body (Cancer Research UK, 2009). This would be essentially useful during the radiotherapy process, where these can be used to lower the dose of radiations on the organs. It is known that in case of radiation therapy treatment, the doses are given in fractions over a certain period of time (to prevent major side effects), which may vary from few weeks to months. Thus, before each fraction of radiation dose, computed tomography (CT) scan of the patients is done to determine the exact location of the tumor or cancer cells. So in case the full dose has been divided into 30 fractions, then the patient has to undergo 30 CT scans, each before a fractional therapy. The machine used for the radiation therapy planning is known as the simulator (Cancer Research UK, 2009). The simulator identifies the position of the tumor and marks the position of radiation on the body with the help of light rays. The radiographer uses ink markers on the body before the actual radiotherapy is begun. These linear ink marks are used by the radiographer for positioning the machine for radiotherapy (Cancer Research UK, 2009). Simulators take the pictures (CT scans) in the form of X-rays, which locates the accurate tumor position for the radiographer to carry out the treatment. During a CT scan, it is essential that the person remains completely still so that the measurements are accurate. In order to insure the correct position supports like neck rest, chest board or arm pole are used (Cancer Research UK, 2009). In case of children it is ensured by giving proper sedatives. Sometimes, under critical condition, extra measures are taken in order to prevent essential organs from being radiated during the therapy. These measures include injecting fluids or dyes which mark the position of vital human organs in the CT scan (Cancer Research UK, 2009). These markers may be given orally, through injections or rectally depending upon the requirement. Using this vital information from the CT scans, a treatment plan for radiation therapy is prepared. This plan indicates the position and direction of the radiations during the therapy, so as to minimize the exposure of healthy cells and organs. The scans generated by a CT scanner are in the form of 2 dimensional (2-D) slides, but by the used of digital geometry processing they can be used to generate a 3 dimensional (3-D) images of the body (Nordqvist, 2009). This can be achieved by integrating all the slides (along the same axis) together using a computer system. The CT scan can be understood as a technically advanced format of X-rays machines. The x-rays images are produced by the projection of a broad beam of x-rays on a film after passing through the body (Medindia, 2010). It provides a 2-dimentional projection of the body, where much of the information is lost. In case of CT scan, a thin beam of x-rays is absorbed by the detector after passing though the patients body (Medindia, 2010). Like the x-ray process, the CT scanning is a painless process for the patients but has been known to be accompanied with some side effects. These side effects may vary from the patient to patient depending upon the amount of radiation dose and health of the patient. The detailed discussion on the health effects of CT scanning has been discussed in the later sections of the project. Theory In order to understand the working of a computed tomography (CT) scanner it is essential to understand the properties of ionizing radiations (X-rays) used in the scanning process. The electromagnetic radiations are the arrangement of electric-field and magnetic-field vectors perpendicular to each other and also perpendicular to the propagation direction of the wave (Resnick et al., 2009). These Electromagnetic radiations have penetrating powers, which are directly dependent on the energy (or frequency) of these radiations. So that radiations with higher frequency have higher penetration powers. Therefore, on the basic the energy, the electromagnetic radiations are categorized as Non-ionizing radiations and Ionizing radiations. Non-Ionizing radiations refer to the electromagnetic radiations which have energy lower than that required for an atomic ionization (MIT, 2001). The non-ionizing radiations include radio waves, micro waves, visible light etc. These radiations have lower penetration powers. Alternatively the Ionizing radiations are the high frequency radiations which have enough energy to knockout an electron from an atom and thus causing ionization (MIT, 2001). The Gamma rays and X-rays are the common type of ionizing radiations. Even the alpha particles and beta particles emitted in a nuclear reaction are ionizing radiations (MIT, 2001). Due to the higher energy they have higher penetration power than the non-ionizing radiations. Principle of CT Scanning The most important section of a Computed Tomography (CT) scanning is the interaction of the ionizing X-ray radiations with the living tissues in the body. When the ionizing radiations (X-rays) interact with the living tissues in the body, they break up atoms and molecules from the living tissues and disrupt chemical reactions within the body (Zamanian Hardiman, 2005). The intensity of absorption of the x-ray radiations by the body varies depending upon the tissue coming in interaction. Different body tissues have different absorption power, where some are permeable to x-rays others are impermeable (Medindia, 2010). It is due to this difference in the absorption ability of different sections of the body, which results in the generation of a graded pattern in the scans. High density tissues like the bones appear white in the scan while the soft tissues (like brain and kidneys) appear dark. The cavities (like the lungs) are seen as black sections in the scan (Medindia, 2010). Therefore, this gradation in the pattern can be used as method to distinguish different body organs depending upon their absorption capacity. This forms the basic principle behind the working of an X-ray scanning. Radon (1917) was the first to develop the principles of computed tomography (CT) mathematically (Bushberg et al., 2002). According to Radon, with the help of infinite number of projections through an object, it could be possible to produce an image of an unknown object. In case of film imaging (as in conventional X-rays), a two-dimensional (2-D) projection of the body is generated on the film. Due to this, details in the dimension of the body along the direction parallel to the x-ray beam are lost. In order to overcome this drawback (only up to a certain level) projections can be taken along two directions; posteroanterior (PA) projection and lateral projection (Bushberg et al., 2002) (as shown in Figure 4). Increasing the number of scans improves the amount of information but in critical and complex cases where much more details are required. For these critical cases, CT scan is done. The CT scan provides the tomographical image, which is the picture of patients body in the sections or slabs. The thickness of these uniform slabs may vary from 1 millimeter to 10 millimeter (Bushberg et al., 2002), according to the program, depending upon the requirement. Each CT image consists of an array of large number of pixels forming a two dimensional (2-D) image, which corresponds to the same number of three dimensional thin rectangular slabs called the voxel. The voxels are the volume element whereas the pixels are the picture element (Bushberg et al., 2002). Every ray from the X-ray source passes (transmits) through the patient before the transmission measurement is done by the detector. Intensity of the un-attenuated x-ray radiation emitted by the source is Io whereas the intensity of the attenuated radiation after transmitting through the patient is given as It. The intensities Io and It are related by the equation (Bushberg et al., 2002):   Ã‚  Ã‚  Ã‚  Ã‚  It=Ioe-ÃŽ ¼t   Ã‚  Where;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚ µ is the total linear attenuation coefficient of the tissue (Smith, n.d.).   Ã‚  Ã‚  Ã‚  Ã‚  t is the distance travelled by the radiation in the tissue i.e. the tissue thickness. The coefficient  µ is dependent on the atomic number and electron density of the tissues (Smith, n.d.). Higher the atomic number and electron density of the tissues, higher would be the attenuation coefficient (Smith, n.d.). This form the basic principle of CT scanning, that different tissues have different level of attenuation properties depending upon their atomic number and electron density. For every measurement, the overall attenuation coefficient is calculated using the above equation. During a complete 360o ­ scan, various transmission measurements for the intensity of X-ray photon are done. Using these intensity measurements specific attenuation values are allotted to every voxel (volume element). These attenuation numbers are directly proportional to the linear attenuation coefficient. The average of these attenuation values is called the CT number (Smith, n.d.). These values can be arranged on a linear scale, the units of which are called the Hounsfield units (HU). The scale for modern CT scanners varies from approximately -1,000 to 3,000 HU. The attenuation scale is based on binary system and therefore the exact values range from -1,024 to +3,071, with a total of 4,096 (or 212) attenuation numbers. Here, the lower represent the black section while the higher values represent the white section of the CT image. On this scale the attenuation value of water is zero HU and that of air is -1,000 HU (Smith, n.d.). Both of these values act as the reference points. Construction of a CT scanner CT scanner is a complex machine, but the basic structure is simple. A common CT scanner has been shown in Figure 2. Two most important parts of a CT scanner are the X-ray source and detector. The source and detector are placed in a circular structure, which has a shape similar to a doughnut. This doughnut shaped circular opening is called the gantry (RadiologyInfo, 2009), with an inner (opening) diameter varying from 60 cms to 70 cms. The X-ray source and detector are placed exactly (diagonally) opposite each other, so that the radiations emitted by the source pass through the body and the transmitted radiations are measured by the detector. The x-ray source and detector system in the gantry is motorized to rotate around the patient for measurements in different projection angles. The rational speed of the system is adjusted according to the detectors ability to measure and convert the x-ray beam into electronic signal. Cobalt (60Co) is generally used as the source of x-rays in the CT scanners. The detector used in CT scanner consists of an array of detectors in a slightly curved shape (like a banana). This curved shape is especially useful in fan-shaped beam projects. Two types of detectors are generally utilized in the CT scans; solid state or scintillation detector and Xenon gas detector (Reddinger, 1997). But the solid state detectors with scintillators like Cadmium Tungstate (CdWO4), yttrium, gadolinium ceramics etc are commonly used (Bushberg et al., 2002). The principle of the scintillation detector is that, when it is struck by a x-ray photon, it produces light. This light signal is then transformed to electrical signal with the help of photodiode. The Depending upon their structure, the detectors are categorized into two categories; single detector array and multiple detector array. Another essential part of a CT scanner is the motorized examination table. The table is controlled to move in and out of the gantry during the scanning process. As the position of the x-ray source and detector is fixed therefore the section being scanned is controlled by the movement of the examination table. For a better scan it is necessary that the patient remains completely still. To insure this table is equipped with neck rest, chest board and arm pole (Cancer Research UK, 2009). The detector measures the intensity of the radiation and converts them into electrical signals. These raw signals are analyzed and manipulated by the computer to convert them into images which can be understood by the radiologists and the technicians. Multiple computers are required in a CT scanner. The main computer that controls the operation of the entire system is called the host computer (Imaginis, n.d.). The computers and controls are located in a room adjoining the scanning room. This prevents the technicians and the radiographer from exposure to x-rays. Scanning Procedure in a CT scanner Initially the patient is positioned on the examination (or scanning) table in a flat upright posture (face towards the roof). In order to insure the correct and stationary position, straps and pillows may be used along the body. Once the patient is correctly positioned on the scanning table, the motorized table moves the patient into the circular opening of the CT scanner (FDA, 2010), which the x-ray radiations are projected on the patient from the scanning. For a particular position of the x-ray source and detector, the rays from the source pass through a region called the projection or view. There are two different types of projection geometries that are used in CT scanning; parallel beam geometry and fan beam geometry. In the parallel beam geometry, the rays projected on the patient are parallel to each other whereas in fan beam geometry, the rays diverge from the source in the shape of a fan (Bushberg et al., 2002) as shown in Figure 7. The fan beam projections are the most commonly in used x-ray projections in the CT scanners. The X-ray tube is attached with a collimator which controls the thickness of the fan beam. This thickness (of the fan beam projection) determines the width of the tissue slide in the scanning process. It is through the collimator that the slice thickness is varied between 1mm to 10mm (Smith, n.d.). The x-ray source and detector rotate around the patient (for imaging) in a circular motion such that they always remain exactly (diametrically) opposite to each other (as shown in Figure 7). During the rotation the source keeps emitting x-rays which are attenuated after passing through the patient. For a single projection (or slice), the x-ray source and detector make a complete 360o rotation around the patient. During the rotation the detector takes a large number of snapshots of the absorbed X-ray beam at different projection angles. A single image may involve approximately 800 rays and there can be up to 1,000 different projection angles (Bushberg et al., 2002). Therefore for a single projection (one slice), the detector does nearly 800,000 transmission measurements (Bushberg et al., 2002). The scanning of a single projection generally takes around 1 sec (for axial CT scanners) (FDA, 2010). Once all the transmission measurements (complete 360o) for a projection (or slice) are completed, the motorized table moves along the axis of the gantry so that the next slice of tissues forms the projection view. The process is continued till the complete required section of the body has been scanned. In the traditional CT scanners, the table moved on to the next projection (slice) only when the scanning of the previous was completed. Such conventional type of scanning is called the axial scanning. But in modern CT scanners, called the helical or spiral CT scanners, the rotation of the x-ray source and detector is accompanied with the uniform movement of the examination table, thus producing a helical projection. The helical CT scanning has been shown in Figure 9. These modern helical CT scanners are much faster than the traditional scanners due to continuous scanning process. They have been reported to take nearly half the time for scanning as compared to the traditional CT scanner s. In order to analyze and study the cardiac structure which is under constant motion, even helical CT is ineffective. For such applications a special CT scanner with an exposure time of 50ms and a maximum exposure rate of 17 images per second are used (Smith, n.d.). These scanners, called the cine CT, freeze the cardiac motion due to extremely low exposure time resulting in a sharp image (Smith, n.d.). These scanners use electron beam to generate x-rays, thus are also known as Electron Beam Computed Tomography (EBCT). In the CT scanning process large volume of data and operations are required to be processed, which is achieved with the help of multiple computers. The detector converts the intensity measurements of the attenuated x-rays in to electrical signals. The main computer, called the hub computer processes these signals and converts them into an image. These images can then be analyzed for radiotherapy planning. Result Computed Tomography (CT) has become an invaluable medical tool. It provides detailed 3-D images of various sections of the body like pelvis, soft tissues, lungs brain, blood vessels and bones (Nordqvist, 2009). Generally, CT scanning is the preferred method of diagnosing different types of cancers like liver, lungs and pancreatic cancers (Nordqvist, 2009). The tomographic images produced by the CT scan provide specific location and size of the tumor along with the details of affected tissues in the proximity of the tumor. This is especially advantageous in planning, guiding, and monitoring therapies like radiotherapy (FDA, 2010). CT scanning has various benefits over other traditional diagnostic techniques; some of the benefits are (RadiologyInfo, 2009): It is non-invasive, painless and extremely accurate. A major advantage is the ability to identify and distinguish bones, soft tissues and blood vessels in the same image. It also provides real time images which cannot be done in conventional X-rays. This technique is fast and simple; and is extensively used to locate internal injuries after accidents. It is less sensitive towards patient movement as compared to MRI. CT scanning can be used on patients with medical implants unlike the MRI. For an effective radiation therapy treatment, it is necessary that only the tumor is irradiated while minimum damage occurs to the surrounding health (normal) body tissues (Badcock, 1982). This is achieved with the help of CT imaging technique. In a study by Badcock (1982), 186 patients with various malignancies were studied and it was found that in nearly 39% of the treatment cases CT scanning was valuable in the assessment of the radiationdose calculation (Badcock, 1982). According to his study, CT scanner resulted in an alternation in target dose by more than 5%, (as compared to the traditional methods) in 27% of the patients (Badcock, 1982). The result has been shown in the table below. The mean alternation was 6.5% of the target dose and usually resulted in reduction of dose per fraction by factors upto 35% (Badcock, 1982). Even with these advantages, the adverse affect of the ionizing x-ray radiations cannot be neglected. Various experiments and researches have consolidated the fact that ionizing radiations like x-rays, gamma rays etc have adverse effect on living tissues. Zamanian Hardiman (2005) have explained that when high energy ionizing radiations interact with living tissues they strip-off atoms and molecules from them. This disrupts the chemical reaction within the body and failure in organ functioning (Zamanian Hardiman, 2005). The adverse effects of ionizing radiations were seen shortly after its discovery in 1890s, with a scientist involved in the study of radioactivity were reported with skin cancer in 1902. But is was not until 1944, that the role of radiations in causing leukemia in human was first documented, mainly in radiologists and physicists (Zamanian Hardiman, 2005). In recent years the use of x-rays has extensviely increased in medical field for diagonostic and treatment application. According to the U.S. Environmental Protection Agency, X-ray deveices are the largest source of man-made radiation exposure (US_EPA, 2007). According to NCRP Report No. 160 (2006), the average annual effective dose per individual in the US population, from all sources has increase from 1.7mSv in 1980s to 6.2mSv in 2006. This increase is mainly attributed to the striking growth of high dose medical imaging procedures that utilize x-rays and radionuclides (NCRP, 2008). Such man-made devices include X-ray machines, CT scans etc. CT scans, especially result in high dose x-ray exposure, with nealy 100 times the exposure dose as compared to standard x-ray equipments (Coach, 2008). Some of the major risks associated with CT scanning are: It is well documented that ionizing radiaitons like x-rays have the ability to cause cancer on exposure. Therefore, the CT dose in radiotherapy increase the probabilty of cancer in the future. Even though only 4% of the total x-ray examinations are CT scans, they account for more than 20% of the radiation dose to the population by medical x-rays (King Saud University, 2004). In general, the effective dose in a CT scan procedure ranges from 2 mSv to 10mSv, which is nearly equivalent to the amount of radiation that a person receive from the background exposures in three to five years (RadiologyInfo, 2009). A CT scan during preganacy make cause serious illness or even birth defects in the unborn baby (FDA, 2010). Children are more sensitive and vulnerable to x-ray exposures than the adults, therefore their CT scanning should be done only under extremely essential and necessary conditions. Women have higher risk of developing cancer in the lifetime, as compared to men under same levels of exposure (FDA, 2009). In some rare situation of high-dose prolonged radiation exposure, the x-rays can cause adverse effects like skin reddening (erythema), skin tissue injury, hair loss, cataracts etc (FDA, 2010). In a study, Sawyer et al (2009) estimated the effective dose resulting from a cone beam CT scanning for planning of radiation therapy using thermoluminescent dosemeters (TLDs) for organ dose and using International Commission on Radiological Protection (ICRP) 60 tissue weighing factor (Sawyer et al., 2009). The results obtained for effective dose from TLD measurements and ICRP 60 weighting factor, for breast, pelvis and head simulation have been shown in the table below. The scanning process results in the exposure of the normal tissues outside the treatment volume (Waddington McKenzie, 2004). It is thus important to analyze the effect that the irradiation caused by the CT scanning process has on the patients body. In a study, Waddington McKenzie (2004) analyzed the propability of developing cancer from the irradiations caused by the extended field portal imaging techniques, the results of which are given in the table below (Waddington McKenzie, 2004). In order to illustrate a real life situation, the calulations in the study were done for an average man with a height of 170 cms and weight of 70 kgs (Waddington McKenzie, 2004). Therefore, these values may change depending upon the height, weight and tumor size of the patient. Discussion Various studies have been done to statistically evaluate the effect of the ionizing radiations on the human health. These risks have severely amplified due to the rapid increase in the number of CT scans for diagnostic applications. CT scans form nearly 5% of all procedures used in diagnostic radiology in the developed countries (Wrixon et al., 2004). In U.S., nearly 70 million CT scans were done in 2007 as compared to just 3 million done in 1980 (Steenhuysen, 2009), this includes more than 4 million children in 2006 (Brenner Hall, 2007). Thus, according to the NCRP Report no. 160, the average radiation dose per person has increased from 3.6 mSv in early 1980s to 6.2 mSv in 2006 (NCRP, 2008). Steenhuysen (2009) has reported that the radiations from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 people in America (Steenhuysen, 2009). These stats explain the level of exposure caused by the CT scans. According to estimates by Amy Berrington de Gonzalez of the National Cancer Institute,