Improvements to an optical scintillator imaging-based tissue dosimetry system

Area of Science:

• Medical Physics
• Radiation Oncology
• Dosimetry

Background:

• Accurate surface dose measurement is critical for total skin electron therapy.
• Previous methods using optical emission from plastic discs showed promise but required improvements in robustness and sensitivity.
• Existing techniques can be time-consuming and may require postprocessing.

Purpose of the Study:

• To enhance the robustness and usability of plastic scintillators for surface dose measurement.
• To improve the sensitivity of the optical imaging system for better detection of scintillator emission.
• To enable more rapid, remote, and accurate dosimetric information during total skin electron therapy.

Main Methods:

• Modified plastic scintillators with protective coatings and adhesive backing for improved handling and disinfection.
• Enhanced the optical imaging system by optimizing camera quantum efficiency to match scintillator emission spectra.
• Validated measurements against ionization chambers and optically stimulated luminescence detectors (OSLD) on phantoms and patients.

Main Results:

• Modified scintillators showed minimal change in response linearity after coating, adhesion, and disinfection (<0.02% change).
• The enhanced imaging system achieved <3% difference compared to OSLD measurements in patient imaging.
• Scintillation detection sensitivity was significantly enhanced (25x), and Cherenkov emission was suppressed (7x).

Conclusions:

• The improved scintillators and imaging system provide a robust, sensitive, and accurate method for real-time surface dose measurement in total skin electron therapy.
• Enhanced system sensitivity allows for potential reduction in dosimeter physical dimensions without compromising measurement accuracy.
• This advancement facilitates rapid, remote, and postprocessing-free dosimetric data acquisition, improving clinical workflow.