ABSTRACT
This chapter addresses the many aspects of accuracy requirements, especially as related to three-dimensional (3D) dosimetry. It describes the meaning of 3D dosimetry, focuses on dose measurement and considers that calculations used in treatment planning in a more restricted manner. The chapter discusses some of the nontechnical limitations influencing dosimetry accuracy requirements. It reviews the literature describing what has been practically achieved in 3D dosimetry with hardware and software tools. The level of accuracy required in radiation therapy is primarily driven by the clinical response of diseased and normal tissue to radiation and the realistic acceptance of what dosimetric accuracy can be practically achievable using instrumentation. Prior to commencement of the patient treatment process, the radiation machine must be commissioned for clinical usage. Computerized radiation treatment-planning systems yield the 3D dose distributions upon which clinical treatment decisions are made; they are therefore recognized as being at the heart and along the critical path of the radiation treatment process.
