ABSTRACT
This chapter presents the standard computational methods developed for internal radiation dosimetry, such as the Medical Internal Radiation Dose (MIRD) schema’, have generally been based on ‘average’ kinetic and anatomic models. It reviews the concepts associated with the computational approaches to internal radiation dosimetry. One of the most widely used and authoritative approaches for internal dose calculations in medicine was developed by the MIRD Committee of the Society of Nuclear Medicine and generally is referred to as the ‘MIRD schema’ or ‘MIRD formalism’. Even though the standard anthropomorphic models used in the MIRD schema represent normal human anatomy and thus do not include tumours, the schema can be adapted to patient-specific normal-organ dosimetry for planning radionuclide therapy based on the maximum tolerated activity. Dosimetric quantities may be characterized as ‘stochastic’ or ‘deterministic’. Radiation dosimetry deals with the determination of the amount and the spatial and temporal distribution of energy deposited in matter by ionizing radiation.
