MO-B-211-01: Linac-Based IMRT/VMAT Commissioning and QA Program Development

Intensity modulated radiotherapy (IMRT) has been used clinically for many years. Reports from the RPC indicate that up to 30% of the institutions fail to pass RPC IMRT credentialing process on the first attempt. While volumetric modulated arc therapy (VMAT) has been introduced more recently, it has quickly gained wide clinical use. In spite of the long history with IMRT and rapid adoption of VMAT, commissioning and developing a quality assurance (QA) program continues to be a challenge especially in busy departments. These points indicate that a review of commissioning and quality assurance for IMRT is still very much needed. In this session, the development of an overall IMRT/VMAT QA program, the role of team members and on-going program functions will be described including aspects of both quality and safety. General issues and specifics of IMRT/VMAT commissioning and quality assurance will be covered. While the general principles of commissioning and QA apply to any device capable of intensity-modulation, specific examples will be provided for Elekta and Varian linear accelerators. Strategies for commission and useful checklists will be discussed as well as some differences between Elekta and Varian technologies. There will also be a focus on practical advice towards the implementation and on-going QA of linac-based IMRT and VMAT. Patient- specific QA strategies along with the comparison of different QA equipment and techniques will be presented. Lastly, differences will be highlighted between IMRT and VMAT for patient-specific QA.

1. Understand approaches to IMRT/VMAT commissioning and QA 2. Describe most relevant issues in patient-specific QA for IMRT/VMAT 3. Discuss issues with IMRT /VMAT QA equipment and techniques.