Patient-specific quality assurance in stereotactic radiotherapy: clinical practice in absence of guidelines - status and new approach from the DGMP working group for physics and technology in stereotactic radiotherapy.

Abstract

IntroductionGuidelines on how to perform patient-specific quality assurance (PSQA) in stereotactic radiotherapy (SRT) are currently not available. In this context, guidelines for modulated techniques like IMRT or IMAT do include descriptions of PSQA. However, commonly used quality assurance (QA) devices, methods, and evaluation metrics are not sufficiently suitable for small-field conditions. Consequently, these guidelines cannot generally be applied to stereotactic radiotherapy. The aim of this work is to assess the limitations of current clinical practice and provide guidance on choosing QA methods given the extensive QA requirements. Additionally, we will present a method for evaluating comprehensive PSQA programs, identifying blind spots, and supporting the selection of suitable devices and methods to overcome them.Methods/resultsWe reviewed available literature, especially guidelines, and identified main issues in today's PSQA practice for SRT by performing surveys among users and vendors. Current QA equipment, software, and methods were assessed and analyzed. Independently, we defined the scope of an appropriate PSQA for SRT. Subsequently, we related this to available devices and methods in a vendor-neutral manner, resulting in a toolkit for evaluation of site-specific PSQA programs in SRT. The approach and result were reviewed by a group of experts.Discussion/conclusionNo single QA solution or method can account for all PSQA needs for SRT. In addition, properly choosing PSQA evaluation metrics is key for a meaningful verification process. The heterogeneity of SRT implementations throughout different sites encompasses different needs and hinders the creation of a static guideline. In the absence of such, we derived a best option decision-making toolkit for optimizing a PSQA program to be used in the environment of stereotactic radiotherapy.