Room: Stars at Night Ballroom 1
Purpose: The system described in this study is comprised of a time-gated intensified camera and plastic scintillating targets that are directly attached to the patient skin surface. Light emission from these scintillators is converted to dose via a custom fitting algorithm. This study assesses the clinical performance and physical characteristics of this new scintillator imaging-based surface dosimetry system.
Methods: To test the effects of dose rate (100 â€“ 1000 MU/min), incident energy (6 â€“ 18 MeV and MV), temperature (15 â€“ 40 Â°C), and radiation damage (<15,000 Gy) on dosimeter performance, scintillators (15 mm âŒ€ x 1 mm thick) were attached a flat-faced phantom and irradiated with photon and electron beams. Scintillator-to-scintillator variation (n = 30 dosimeters), as well as the effects of varying dosimeter diameter (5 â€“ 30 mm) and thickness (0.65 â€“ 3.13 mm) on scintillator light output, were also evaluated using this same setup. The emission spectra and impact of dosimeter thickness on surface dose were determined.
Results: Scintillators were found to have a 422 nm wavelength of maximum emission and increased underlying surface dose by 3.9% (comparable to standard optically stimulated luminescence detectors, OSLD). Scintillator light output increased linearly with thickness (~1.9Ã—/mm) and all dosimeter diameters were able to accurately measure surface dose. The thinnest and thickest dosimeters increased surface dose by 2.6% and 6.6%, respectively â€“ these values are comparable to commercially available technologies like OSLDs. Within the batch of scintillators, there existed a variation of 0.3 Â± 0.2% in light output. Scintillators were found to function independent of temperature, energy, radiation damage and dose rate.
Conclusion: Scintillators utilized in this study can provide accurate surface dose information remotely and rapidly without any post-exposure processing. These dosimeters are a viable alternative to existing surface dosimetry technologies and have the potential to improve associated clinical workflow.
Funding Support, Disclosures, and Conflict of Interest: M. Jermyn is an employee and B. Pogue is a president of DoseOptics LLC. P Bruza is principal investigator in SBIR subaward B02463 (prime award NCI R44CA199681, DoseOptics LLC).