The use of radionuclide therapy has been established in clinical practice for many years, the earliest and most widely used application being radioiodine therapy of the thyroid.    To date however, prescribed activities have been primarily empirical and the use of dosimetry to inform the management of radionuclide therapies is significantly less widely applied.    This publication is intended to be read by scientific and medical practitioners and aims to provide them with a comprehensive overview of the theory and methodology of radionuclide dosimetry.    The topics presented here are wide ranging and the content should be of interest to both the beginner and the more experienced practitioner.

The methodology of radionuclide dosimetry is essentially the same whether the radiopharmaceutical is being administered for diagnostic or therapeutic purposes.   Therefore, several chapters of this publication are also relevant to those who have a need to perform dosimetric calculations for diagnostic applications; either alone or as an introduction to more detailed reviews.