Technical Note: Scintillation markers for real‐time visual source tracking during skin high dose rate brachytherapy

Abstract

Background Treatment misadministration during high dose rate (HDR) brachytherapy is mainly caused due to gross errors in incorrect manual entry of catheter length and manual connection of hardware. The probability of these errors increases with increasing complexity of a surface applicator. A simple, real‐time visual verification method was developed using a scintillator to enhance quality assurance (QA) measures for HDR surface brachytherapy and thus reduce manual errors and improve patient safety. Materials and methods Scintillation markers were fabricated from cerium‐doped lutetium yttrium orthosilicate (LYSO) embedded in a polymer compound to form 5‐mm diameter markers. To verify catheter‐transfer tube connections, markers were attached to each channel of a Freiburg flap and irradiated with an 192Ir source. To determine if the source reached the edge of a target, markers were placed along the periphery. The HDR source was visually tracked by following the illumination from the markers. The response of the markers was also verified in the presence of thermoplastic material overlaid on the Freiburg applicator. Results Scintillation markers emitted intense blue visible light upon irradiation when the HDR source was beneath the marker, verifying the source’s presence in the correct catheter. The signal was clearly visible even when the marker was placed on top of the thermoplastic material covering the Freiburg Flap. Crosstalk from adjacent catheters was <50% of the maximum light intensity. Conclusion Scintillation markers and paint were developed to successfully meet the challenge of visually tracking of HDR source during brachytherapy by surface applicators. This direct visualization of source allows real‐time catheter verification during treatment, and correct superficial target coverage, thus preventing a medical event. It can easily be integrated into pre‐existing QA program.

Radioactive source localization employing resistive electrode array (REA) detector

“…Other potential uses of the REA localization capability is in Radioisotope Identification (RIID) in health safety and national security [6]. Various detectors have been used in radioactive source localization [7][8][9][10][11][12][13][14]: radiosensitive films, at panel detectors (Electronic Portal Imaging Device (EPID)), gamma camera, photon counting detectors, scintillators, and others. Typically the detector is at a fixed position and radioactive sources are either static or moving.…”