ABSTRACT
Multileaf collimator (MLC)-based intensity-modulated radiotherapy (IMRT) provides the most accessible and cost-eective means of sculpting radiation dose to the tumor while minimizing dose to normal tissues. With increasing complexity of IMRT planning and delivery methods comes the need for more sophisticated quality assurance (QA) processes that can capture errors in the radiation therapy delivery chain. ese QA processes must strike a careful balance between accurate estimation of delivered dose and eciency. Before discussing patient-specic IMRT QA methodologies or processes, acceptance testing, and QA of CT simulation, treatment planning and delivery systems must be well dened, controlled, and their associated errors in the treatment delivery chain understood. Although potential sources of systematic error have been addressed in other sections of this chapter, their importance in patient-specic QA is vital in MLC-based IMRT. Details of linac and MLC (Kutcher et al. 1994; Klein, Hanley, and Bayouth 2009), IMRT acceptance testing (Ezzell et al. 2003, 2009), and inverse treatment planning (Fraass et al. 1998) will not be discussed in this chapter. e purpose of this chapter is to describe the important aspects of QA of patient-specic MLC-based IMRT.
