A comprehensive phantom with multi-detector inserts for pre-treatment quality assurance in stereotactic ablative radiotherapy

Stereotactic ablative radiotherapy (SABR) is an advanced high precision radiotherapy procedure where a high dose of radiation is delivered in a few fractions. Pre-treatment quality assurance (QA) is conducted prior to treatment to ensure the planned dose is delivered precisely. Several types of detectors have been explored for the use of pre-treatment QA in SABR. This study discusses the design of an in-house phantom with inserts designed to accommodate multiple detectors such as ion chambers, films, alanine, optically stimulated luminescence (OSLs), thermoluminescence dosimeter (TLDs), diodes, diamond detectors, and presage dosimeter. The study also presents some of the measurement results performed for selective treatment sites. The inserts were designed using Perspex and 3D printed materials. The Presage dosimeter provided a three-dimensional view of the delivered dose for SABR plans and matched closer to the planned dose. Most of the detectors/dosimeters explored in this study demonstrated measured results within 3% of the planned dose.