Seven-probe fiber detector for time-resolved source tracking in HDR-brachytherapy: Pre-clinical experimental...

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Biomedical Engineering

Background:

• In vivo dosimetry (IVD) is crucial for verifying high-dose-rate brachytherapy (HDR-BT) delivery.
• Time-resolved techniques like source tracking offer real-time error detection but have been limited in clinical scenarios.

Purpose of the Study:

• Evaluate a compact, biocompatible Seven-probe Scintillator Detector (7SD) for monitoring HDR-BT.
• Assess the 7SD's ability to detect source insertion errors across diverse HDR-BT techniques.

Main Methods:

• Developed a 7SD using Gd2O2S:Tb scintillator probes coupled to optical fibers.
• Tested the 7SD in a phantom with an Ir-192 HDR afterloader, acquiring data at 0.06s intervals.
• Calibrated the probe experimentally and confirmed biocompatibility via cytotoxicity tests.

Main Results:

• Analyzed 4040 dwell positions with high accuracy (99.5% identified).
• Measured dwell positions deviated minimally (0.224 mm radial, 0.077 mm axial) from planned values.
• Detected 99.4% of positions within a 1 mm reliability threshold, identifying systematic afterloader errors.

Conclusions:

• The 7SD is suitable for time-resolved IVD in HDR-BT, enhancing monitoring volume and accuracy.
• The system can detect afterloader malfunctions, improving HDR-BT setup integrity.
• The 7SD's capabilities, biocompatibility, and compatibility suggest strong potential for clinical implementation.