A plastic scintillation dosimeter for high dose rate brachytherapy.

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomedical Engineering

Background:

• Accurate in vivo dose verification is crucial for brachytherapy treatments.
• Existing dosimeters often lack the required real-time readout and small size for brachytherapy applications.
• Fiber optic scintillation dosimeters offer a promising solution due to their small size and potential for real-time measurements.

Purpose of the Study:

• To develop and characterize a novel fiber optic scintillation dosimeter (BrachyFOD) for in vivo brachytherapy dose verification.
• To evaluate the dosimetric properties of the BrachyFOD, including its performance with an Iridium-192 source.
• To confirm the suitability of the BrachyFOD for real-time, in vivo brachytherapy applications.

Main Methods:

• Development of two BrachyFOD dosimeter sizes (2.2 mm and 1 mm external diameter).
• Characterization of dosimetric properties: depth dose relation, angular dependence, temperature dependence, and energy dependence.
• Assessment of background signal interference (Cerenkov and fiber fluorescence) using an Iridium-192 HDR brachytherapy source.

Main Results:

• The BrachyFOD dosimeters were successfully developed in two sizes suitable for brachytherapy.
• Key dosimetric characteristics were determined, showing reliable performance.
• Background signals did not significantly impact performance in most clinical geometries.
• Real-time readout capability with intervals less than 0.5 seconds was achieved.

Conclusions:

• The developed BrachyFOD scintillation dosimeter meets the requirements for real-time in vivo dose verification in brachytherapy.
• Its small size, real-time readout, and acceptable dosimetric characteristics make it a promising tool for clinical use.
• The BrachyFOD can enhance the safety and accuracy of brachytherapy by providing immediate dose feedback.