ABSTRACT
This chapter explores treatment planning, the associated dose calculation methods, and techniques that are frequently employed to achieve high-quality plans. Using the dose calculation algorithm a model for the beam can be built in the treatment planning system. The penumbra is wider in the presence of the inhomogeneity due to the longer range of the electrons, and this effect is larger in a higher energy beam because the electron range is larger. The magnitude of the effect described depends greatly on the number of beams used. The size and shape of the kernel depend on the energy of the beam, and it is calculated using Monte Carlo methods of numerical simulation. The size of the kernel is also scaled according to the density in the patient. That is, in regions of lower density the kernel is larger to account for the fact that the range of the electrons is larger.
