TLD and OSLD dosimetry systems for remote audits of radiotherapy external beam calibration

• Published in: Radiation measurements Vol. 106; pp. 412 - 415
• Main Authors: Alvarez, P, Kry, S F, Stingo, F, Followill, D
• Format: Journal Article
• Language: English
• Published: England 01.11.2017
• Subjects: OSLD; output verification; remote audit; TLD
• ISSN: 1350-4487
• DOI: 10.1016/j.radmeas.2017.01.005

The Imaging and Radiation Oncology Core QA Center in Houston (IROC-H) performs remote dosimetry audits of more than 20,000 megavoltage photon and electron beams each year. Both a thermoluminescent dosimeter (TLD-100) and optically stimulated luminescent dosimeter (OSLD; nanoDot) system are commissioned for this task, with the OSLD system being predominant due to the more time-efficient read-out process. The measurement apparatus includes 3 TLD or 2 OSLD in an acrylic mini-phantom, which are irradiated by the institution under reference geometry. Dosimetry systems are calibrated based on the signal-to-dose conversion established with reference dosimeters irradiated in a Co-60 beam, using a reference dose of 300 cGy for TLD and 100 cGy for OSLD. The uncertainty in the dose determination is 1.3% for TLD and 1.6% for OSLD at the one sigma level. This accuracy allows for a tolerance of ±5% to be used.