Abstract
Previous work (see ibid., vol.16, 577) has been continued to determine the practical capabilities of the system. A higher resolution Ge(Li) detector has been used to portray the scattering along the lines of passage of a 137Cs gamma -ray beam, and from these results it is possible to construct density cross-sections of the body. The limitations are shown to be due to (a) signal/noise arising from multiple scattering in the body and (b) resolution, which is governed by the finite beam width and finite aperture needed in front of the crystal. A suggested design of a twin-headed machine for clinical use is given.