This chapter sets out the methods by which the dose delivered by brachytherapy sources

can be calculated. It is important that the physicist has a clear appreciation of the theoretical

basis of these calculations so that, whether applying a manual calculation system or using a

computer algorithm, the correction factors that are implicit in the algorithm and those that

must be applied explicitly are fully understood. The issue of dose calculation is considered first

in a generic way, and then the calculation of dose for specific sources will be considered.