AAPM TG report 312: Acceptance testing, commissioning, and periodic quality assurance of ion chamber and diode detector arrays

Multi-dimensional detector arrays have been adopted in radiation therapy clinics by medical physicists for various types of measurements. Typical applications of such devices include plan quality assurance (QA) measurements, periodic QA measurements for constancy checks of beam flatness and symmetry, as well as dose and beam quality constancy checks for linear accelerators (linacs). The multi-dimensional arrays vary in terms of their size, detector types, and usage. This report provides guidelines to the users on initial and ongoing performance assessments that should be performed to ensure proper functionality of ion chamber and diode multi-detector arrays that are positioned on the linac couch or gantry mounts and used for patient-specific quality assurance (PSQA) and machine QA. The characteristics of the most common detector arrays are provided in this report along with their intended use. After reading this report, the user should understand how to assess the detector array's performance and proceed with its use. The report describes the most relevant array parameters for testing and offers detailed test instructions and frequencies. Test results from the TG members and other clinical users are presented in a table. The tolerances for the parameters with some statistics are recommended based on those test results and other publications. This report is not intended to provide a comprehensive review of linac quality assurance procedures or patient-specific Intensity Modulated Radiation Therapy (IMRT) QA.