Diagnostic Dosimetry

Diagnostic nuclear medicine, more recently also named functional molecular imaging, deals with medical procedures performed to help diagnose a variety of diseases. The procedures are based on the use of tracer amounts of radioactive material, where a radionuclide is attached to a ligand with specific affinity to a physiological, metabolic, or receptor-specific process. To balance the benefit of a procedure, the calculation of the mean absorbed dose in organs and tissues for representative groups of patients is one important parameter in the justification of the diagnostic procedure. This also applies to the use of radiopharmaceuticals to volunteers in clinical research. Specific biokinetic models are created to describes the uptake, turn-over and retention in the human body. Together with mathematically describable anatomical models, representing groups of patients, these are used to estimate the mean absorbed dose in organs and tissues. This facilitate the estimations of the quantity effective dose, which is a dose quantity to estimate the risk to later in life develop a radiation-induced cancer for a group of reference patients. The chapter describes methods for diagnostic internal dosimetry, assessment of biokinetic data for individual patients/volunteers as well as construction of biokinetic and dosimetric models for representative groups of patients.