Study of PRESAGE® dosimeter for end-to-end 3D radiotherapy verification using an anthropomorphic phantom with bespoke dosimeter insert

Abstract

Modern radiotherapy techniques have advanced and become more sophisticated. End-to-end 3D veri cation of the complex radiotherapy dose distribution in an anthropomorphic phantom is important to ensure the accuracy of the treatment delivery. The phantoms typically used are homogenous waterequivalent phantoms and lack of capability to measure the dose in 3D. Therefore, we developed an endto-end 3D radiotherapy dose veri cation system based on MAX-HD anthropomorphic phantom (IMT, Troy, New York) with bespoke intracranial insert for PRESAGE® dosimeter. In this study, several radiotherapy treatment techniques of various levels of complexity, 3D-CRT, IMRT and SRS treatment, were planned for a 20 mm diameter of a spherical target in the brain region and delivered to the phantom. The dosimeters were read out using an in-house optical computed tomography (OCT) imaging system known as 3DmicroHD-OCT. It was found that the measured dose distribution of the PRESAGE® shows good agreement with the measured dose distribution of EBT lm and Monaco TPS with a maximum difference of less than 3% from 3D-CRT, IMRT and SRS treatment planning. The gamma analysis results of PRESAGE® in comparison to EBT lm and Monaco TPS show pass rates of more than 95% for the criteria of 3% dose difference and 3 mm distance-to-agreement. This study proves the capability of PRESAGE® and bespoke MAX-HD phantom in conjunction with the 3DmicroHD-OCT system to measure 3D dose distribution for end-to-end dosimetry veri cation.