ABSTRACT
It is well accepted that Monte Carlo simulation methods offer the most powerful tool for modeling and analyzing radiation transport for radiotherapy applications. One of the most frequent and important uses of Monte Carlo modeling in external beam radiotherapy is the creation of a virtual model of the radiation source. Applications are source design and optimization, studying radiation detector response, and treatment planning. Since the vast majority of radiotherapy is performed with megavolt (MV) photon beams from a linear accelerator (linac), this is also reflected in the research efforts. To a lesser extent, external beam radiotherapy is performed with electron beams, lower-energy photon beams emanating from an x-ray tube, or hadron beams. This chapter will cover the Monte Carlo modeling of photon beams and Chapter 6 will cover the Monte Carlo modeling of electron beams, while other chapters will deal with hadron beams.
