Quality assurance procedures in radiotherapy of brain tumors

Within the wide range of brain tumor types and their various radiotherapy treatments, quality assurance (QA) criteria play a major role. Attention should be paid to the definition of GTV, CTV, PTV, relevant to 3D stereotactic radiotherapy. In fact the need for delivering high doses with acceptable toxicity, requires an interdisciplinary evaluation of the clinical case as well as a millimetric precision and safety. Conventional treatments with collimated beams are however extensively studied and errors and deviations which may impact on treatment protocol, are identified. Possible GTV and CTV under-and overestimation is described by various authors who point out the useful support of sophisticated diagnostic and therapeutic equipment. It is stressed that follow-up helps in the reappraisal of the many items of a QA program to detect errors in set-up or implementation as well as possible inadequacies in the initial treatment planning.