A new approach to the determination of anatomical cross-sections of the body by Compton scattering of gamma-rays

Abstract

Current methods of determining anatomical cross-sections of the body for cancer treatment planning including transaxial tomography have severe limitations and a new method is described depending on the change of wavelength of gamma -rays in Compton scattering. A narrow beam of 137Cs gamma -rays is passed through the body, and the scattered radiation is picked up and analysed by a Ge(Li) detector so that the intensity is portrayed against distance through the body. The primary beam is moved slowly to traverse the whole cross-sectional area and the density pattern so obtained displayed on a cathode ray screen. Problems including limitations of resolution and attenuation of the primary and secondary radiation are studied, and an experimental arrangement, which it is hoped will lead to a practical working system, is described.