First measurements with a plastic scintillation dosimeter at the Australian MRI-LINAC.

First measurements with a plastic scintillation dosimeter at the Australian MRI-LINAC. Phys Med Biol. 2019 Jul 15;: Authors: Madden L, Archer J, Li E, Jelen U, Dong B, Roberts NF, Holloway L, Rozenfeld AB Abstract MRI-LINACs combine MRI and LINAC technologies with the potential for image guided radiation therapy with optimal soft-tissue contrast. In this work, we present the advantages and limitations of plastic scintillation dosimeters (PSDs) for relative dosimetry with MRI-LINACs. PSDs possess many desirable qualities, including magnetic field insensitivity and irradiation angle independence, which are expected to make them suitable for dosimetry with MRI-LINACs. An in-house PSD was used to measure field size output factors as well as a percent depth dose distribution and the beam quality index TPR(20/10) at 10.5 x 10.5 cm2. Measurements were repeated with a Scanditronix/Wellhofer FC65-G ionisation chamber and PTW 60019 microDiamond detector for comparison. Relative differences were calculated between the three detectors, where the mean difference in dose was 1.2% between the PSD and ionisation chamber, 1.9% between the PSD and microDiamond detector and 1.3% between the microDiamond detector and the ionisation chamber. The closeness between the three mean differences in doses suggests that plastic scintillation dosimeters are feasible for relative dosimetry with MRI-LINACs. PMID: 31307025 [PubMed - as supplied by publisher]
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research