CT scanning: The fruit of physics or engineering

Since Roentgen’s discovery of X-Rays in 1895 virtually every conceivable energy source has been used to probe and image the inside of the human body. A review of the historical development of two of the most commonly used imaging techniques, X-Ray computed tomography and diagnostic ultrasound will show that many of the principles of physics on which these are based are very old. It has been engineering developments which have driven progress in medical imaging. The information content of CT and ultrasound scans has doubled every 3 years since their invention. My first CT scanner took 27 seconds to acquire data for a single slice. The latest scanners are 25,000 times faster.

Director, Centre of Medical Imaging, UCL. Bill qualified in medicine at The Middlesex Hospital in 1972 and was appointed their consultant radiologist in 1981, where he was in charge of body imaging. In 1994 he was appointed Professor of Medical Engineering, UCL. In 1989 Bill performed the first laser ablation of liver metastasis, leading to the ablation service that is now well established in the NHS.