Sci-Sat AM: Brachy - 07: Plastic scintillation detector validation for kV dosimetry.

Area of Science:

• Medical Physics
• Radiation Detection
• Dosimetry

Background:

• Plastic scintillation detectors (PSDs) are utilized for radiation measurement.
• Accurate real-time dosimetry is crucial in superficial x-ray therapy and interventional radiology.

Purpose of the Study:

• To characterize the response of PSDs within the diagnostic energy range.
• To propose a fast and adaptable method for real-time dosimetry.

Main Methods:

• A PSD coupled to an optical fiber guided scintillation photons to a photodiode.
• Dose conversion to different media (air, water, soft tissues) was performed using large cavity theory (LCT).
• X-ray tube spectra simulation software and Monte Carlo simulations were used for analysis and confirmation.

Main Results:

• PSDs exhibit energy dependence with low-energy photons, showing a factor of 2 variation between 80 kVp and 150 kVp.
• The proposed method compensated for PSD energy dependence, resulting in a 2.1% standard deviation when converting dose to desired media.
• Percent depth dose (PDD) measurements showed good agreement with Monte Carlo simulations.

Conclusions:

• PSDs demonstrate significant potential for real-time dose measurements in radiologic photon energy applications.
• The developed method enhances the accuracy of PSD dosimetry by compensating for beam hardening effects.