Conceptual basis for calculations of absorbed-dose distributions

For all absorbed-dose calculations, there is a source (or sources) of radiation and a receptor (or receptors) of some of the energy of this radiation, with or without intervening material between the source and receptor. The calculation of absorbed-dose distributions requires specification of the sources and receptors, characterization of their geometrical relationships and consideration of the physical interactions of the radiations involving attenuation, scattering and the production of secondary radiations. All these processes are considered in the basic transport equation, the general theorems and properties and the methods of solution of which are described in the transport theory. This paper is a systematic presentation, discussion and compilation of all the concepts involved. It contains some complicated mathematics that will be of interest to the mathematically knowledgeable, but that should not discourage those not mathematically inclined