Optically stimulated luminescent dosimeters (OSLDs) are radiation detectors commonly used in a clinical setting to monitor the dose to patients undergoing imaging or interventional procedures, especially those involving fluoroscopy. In dose tracking using OSLDs, it is important to consider that photons at the diagnostic energy range are prone to energy spectrum shifts from scattering interactions in the medium and that OSLDs have been reported to yield a somewhat strong energy-dependent response in the diagnostic energy range. This study examines the response of OSLDs exposed to a spectrum of photons in the diagnostic energy range (60-120 kVp), both free-in-air and on the surface of a PMMA phantom, within and just outside of the exposure field. From these measurements, it was observed that the response differs substantially (as high as 30%) in OSLDs irradiated under identical exposure settings but with differences in beam quality and scattering conditions. Furthermore, this study devises a method of weighted averages to calculate the calibration factors for OSLDs exposed to both primary and scatter photons, which were approximately 2-5% less than their corresponding measured values. This study emphasizes the need to develop different calibration factors in the clinical use of OSLDs for diagnostic imaging procedures, especially for procedures in which more precise dose measurements may be necessary.
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