Abstract

This chapter is concerned with the accurate determination of the absorbed dose in gray at the reference depth in a water phantom. This is sometimes known as calibrating the beam and is expressed in terms of a number of monitor units per gray for a given standard field size, Source to Surface Distance (SSD) and beam quality. For a better understanding of some of the concepts discussed in this chapter, the reader should consult Part E on the general characteristics of photon and electrons beams.