ENERGY IMPARTED IN COMPUTED-TOMOGRAPHY

Monte Carlo techniques were used to study a generalized CT dose index D(r) as a function of the radius r of a cylindrical dosimetry phantom. The relationship between D(r) and the energy deposited in the phantom was investigated. For a specified x-ray spectrum, the energy imparted to head or body dosimetry phantoms can be obtained from measured D(r) values. This approach to CT dosimetry permits the energy imparted to phantoms (or patients) to be determined as CT technique parameters, or type of scanner, are changed.