(a) general tests and data acquisition
(b) MLC and IMRT considerations
James C. H. Chu, PhD
Rush University Medical Center
Chicago, IL 60612
(a) Megavoltage linear accelerators are the main treatment delivery machines in many radiation therapy facilities today. The machines employ sophisticated technologies to deliver precisely defined radiation beams for various clinical applications. To make sure that those technologies function properly, the machines should be thoroughly tested before their use in the clinic. The first set of tests should demonstrate the mechanical, electrical, and radiation safety of the machine. Additional acceptance tests are performed to assure that the machine operates within its mechanical specifications and satisfies its radiation beam characteristics requirements. The commissioning data, as a minimum, should include all necessary input data to the treatment planning system and the data to verify the planning system’s output. The need for additional data during commissioning depends on the intended use of the machine. For example, data at large distances away from the field border should be acquired when one intends to combine dose contributions from multiple disjoint beams. As part of a comprehensive quality assurance program, a subset of the acceptance test and commissioning measurements should be repeated at predetermined intervals to assure the safety and quality performance of the machine.