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

Abstract

Abstract Modern radiotherapy techniques have advanced and become more sophisticated. End-to-end 3D verification 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 water-equivalent phantoms and lack of capability to measure the dose in 3D. Therefore, we developed an end-to-end 3D radiotherapy dose verification 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 film 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 film 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 verification.