Book Review
Imagining the Elephant: A Biography of Allan MacLeod Cormack
N Engl J Med 2008; 359:2735-2736December 18, 2008
- Article
Imagining the Elephant: A Biography of Allan MacLeod Cormack
By Christopher L. Vaughan. 304 pp., illustrated. London, Imperial College Press, 2008. $48. ISBN: 978-1-86094-988-3Sixteen years short of the centennial of Wilhelm Roentgen's discovery of the x-ray, the Nobel Committee recognized a signal development in the use of the ray that would revolutionize medical practice. In 1979, Allan MacLeod Cormack shared with Godfrey Hounsfield the Nobel Prize in Physiology or Medicine for the development of computer-assisted tomography. Cormack, unlike Hounsfield, who became famous with the development of the first commercial medical computed tomographic (CT) device in 1973, was relatively unknown while he was working in academia. Investigating what he called the “line integral function,” a basis of CT that was described in the Journal of Applied Physics in 1963 and 1964, Cormack constructed his own prototype scanner to image an asymmetric aluminum and Lucite phantom model of a head with two “tumors,” which he measured with the scanner. Hounsfield's first patent application in 1968 made reference to both of Cormack's earlier papers, but few people outside the field knew of them. Hounsfield's “successive approximation” algorithm, however, was found to be in no way similar to Cormack's reconstruction solution for CT.
This brief book is a fascinating biography. The author, Christopher Vaughan, warmly sketches Cormack as a quietly gregarious man, traces his Scottish parentage and antecedents, follows his schooling and family life in South Africa, and mines the origins of his research into CT at the University of Cape Town, later at Cambridge University, and during his subsequent years in the United States at Tufts University and at the Harvard University Cyclotron Laboratory. Writing this biography required an exhaustive review of documents and many interviews with those who knew Cormack and his work well. Vaughan's own engineering background, his similar position at the University of Cape Town, and his access to Cormack's family and colleagues must have facilitated his gaining insight into the man and his investigations. The narrative is written in an accessible style that aims at an audience wider than the scientific community alone, but when scientific discussion is called for, it is done expertly and lucidly. Minor defects include occasional diversions into extraneous details and vignettes that distract from the central story.
To what extent this book will redress Cormack's undeserved relative anonymity is uncertain, but to those interested in biomedical science and medical imaging, Vaughan's descriptions of Cormack's investigations speak for themselves. The reader will be transported by a fascinating account of a journey of discovery that began with a challenge to accurately calculate isodose curves for clinical radiotherapy and ended with the production of images from a series of line functions.
This book will especially fascinate readers who are interested in how a rotating series of images can create cross-sectional images of the body. Such curiosity helps to explain Vaughan's choice of title, Imagining the Elephant. It reflects the basic idea of tomography: that a single image of an elephant from one perspective hides various aspects of the elephant, which only become more apparent as images from more and more aspects are obtained. Those interested in the history of science are indebted to Vaughan for producing this wonderful biography of Allan Cormack and for creating an expert and vivid description of one of the two streams of discovery that led to the invention of CT.
Reginald Greene, M.D.
Massachusetts General Hospital, Boston, MA 02114
greene.reginald@mgh. harvard. edu
