ABSTRACT
The traditional method of absorbed dose calculation has been based on a simplified Medical Internal Radiation Dose formalism which have been calculated from a generalized geometry. Three-dimensional informa-tion, combined with accurate morphological information, provides better estimates of the absorbed doses since patient-specific geometry and attenua-tion can be included in the calculation. Biological dosimetry has been applied to investigate marrow absorbed dose in radioimmunotherapy and in radionuclide therapy for bone pain palliation. Validation of single-photon emission computed tomography (SPECT) simulations has been carried out for a clinically realistic situation using a computerized version of the experimental Radio- logical Support Devices thorax phantom. Since SPECT and planar imaging provide the underlying information for activity quantification and biokinetics, evaluation and validation of the dosi-metry should also consider reconstruction methods, registration methods of computed tomography and SPECT/positron emission tomography data, scatter and attenuation compensation methods and distance-dependent collimator response corrections.
