Mass-manufacturable scintillation-based optical fiber dosimeters for brachytherapy

Area of Science:

• Medical Physics
• Biomedical Engineering
• Materials Science

Background:

• Minimally invasive, real-time dose monitoring is crucial for effective brachytherapy (BT).
• Current dosimetry methods may have limitations in localized, real-time measurements during LDR-BT and HDR-BT procedures.

Purpose of the Study:

• To design, fabricate, and characterize novel scintillation-based fiber optic dosimeters for brachytherapy.
• To optimize sensor tip design for efficient scintillation signal collection and coupling into polymer optical fiber (POF).

Main Methods:

• Inorganic scintillators (Gd2O2S:Tb for LDR-BT, Y2O3:Eu+4YVO4:Eu for HDR-BT) dispersed in a polymer host were used for sensor tips.
• Non-sequential ray tracing simulations optimized sensor tip shape and size.
• Custom molding on a hot embossing machine was employed for fabrication.
• Dosimetry experiments were conducted in water phantoms.

Main Results:

• The fabricated dosimeters demonstrated consistent average photon count rates for both HDR-BT and LDR-BT applications.
• Photon count rate signals showed minimal sensitivity to variations in sensor tip composition and geometry.
• Ray tracing simulations successfully guided the optimization of sensor tip design.

Conclusions:

• The developed scintillation-based fiber dosimeters show significant potential for in-vivo dosimetry in brachytherapy.
• While individual calibration is still required, the dosimeters offer reliable real-time dose rate monitoring.
• The fabrication method paves the way for potential series production of these advanced dosimetry tools.