Basic concepts and directions in the radiation therapy quality assurance processes of clinical trials.

The radiation therapy quality assurance of clinical trials is internationally recognized as a key factor to control the quality of radiotherapy for its impact on clinical trial's goals. Quality assessment may be performed at different levels and by different means, which are now quite standardized. The optimal radiation therapy quality assurance of clinical trials trade-off to maintain accrual rates, radiotherapy quality and optimize clinical trial research processes is yet to be defined. This article addresses current definitions, processes, limitations and directions.