The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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The discovery of X-rays by Wilhelm Röntgen in 1895 revolutionized most fields of science, the field of medicine included. The fact that some parts of the body are more dense than others means that X-rays can be used to diagnose some medical problems. Bone fractures, for example, are easily examined using X-ray photographs.
This generalization is not true, however, for studies of the brain, whose density is essentially constant in all its parts. In an attempt to apply the new methodologies of X-ray analysis to the brain, Walter E. Dandy (1886-1946) developed a technique for injecting air into brain cavities. The lower density of air made it possible to use X-rays to study normal and abnormal brains. The method was not very effective, however, and often involved considerable risk to the patient.
In 1927, the Portuguese neurologist, Antonio Egas Moniz suggested another solution for this problem. He injected solutions that are opaque to X-rays into the brain's arteries. Blood vessels in the brain then become clearly visible in X-ray photographs. These photographs can be compared with photographs of the normal brain to see where tumors might have displaced blood vessels.
Over the next decade, Egas Moniz and his colleagues published more than 200 papers describing their technique and the results they obtained with it. The technique, known as cerebral angiography, continues to be one of the most valuable methods for studying and diagnosing brain disorders, including detecting aneurysms (sacs in the vessel wall that can burst), blood clots, narrowing or blockage of the arteries, and changes in tumors.