Quality and Safety of Real-Time Brachytherapy Treatments: Clinical Implementation of a Multipoint Scintillation Detector for Treatment Monitoring

Official title

In Vivo Surveillance of Brachytherapy Using Plastic Scintillation Dosimetry: A Clinical Feasibility Study

Overview

This project addresses a key safety gap in High-Dose-Rate (HDR) brachytherapy, where very high, localized radiation doses mean that small geometric deviations in catheter placement or radioactive source positioning can cause clinically significant errors. Incident reports from the Radiation Oncology Incident Learning System (RO-ILS) of the American Society for Radiation Oncology (ASTRO) and guidelines from the American Association of Physicists in Medicine Task Group 59 (AAPM TG-59) identify these events-often occurring between imaging and treatment delivery-as among the most critical. Unlike external beam radiotherapy, brachytherapy lacks a prior phantom-based verification step, making in vivo dosimetry the only real-time method to confirm delivered dose and detect anomalies in dwell time or source position. International bodies such as the International Atomic Energy Agency (IAEA) recommend this approach for quality management and accident prevention. Multipoint plastic scintillation detectors (mPSD) offer water-equivalent, real-time measurements and can enable three-dimensional (3D) radioactive source tracking, but their clinical use remains limited due to integration challenges and the absence of well-defined alert thresholds. The project aims to implement a real-time in vivo monitoring solution using an mPSD at the Centre régional intégré de cancérologie (CRIC) of Lévis, Québec (QC) for HDR gynecological and prostate brachytherapy. Objectives include: (1) demonstrating clinical feasibility and integration within existing clinical workflows; (2) validating the accuracy and precision of dose, dwell-time, and source-position measurements under clinical conditions; and (3) developing practical alert thresholds to identify common deviations. The central hypothesis is that mPSD technology can provide reliable, reproducible real-time measurements without lengthening procedures or disrupting clinical workflow. The methodology relies on adapting the HYPERSCINT® platform for HDR in vivo use. A custom mPSD, consisting of several scintillators along a single optical fiber, will be insertable into a 6-French (6F) catheter. Phase 1 focuses on feasibility and integration, including HDR-specific calibration, definition of detector insertion scenarios, integration of acquisition hardware, and staff training. Phase 2 validates performance in at least 20 patients. Planned treatment parameters and time-stamped detector signals acquired at 1-10 hertz (Hz) will be used to reconstruct delivered dose, dwell times, and source-to-detector distances. Measurement accuracy and reproducibility will be quantified using mixed-effects statistical models. Phase 3 establishes preliminary alert thresholds based on deviations in dose, time, and position, along with visualization tools such as Bland-Altman plots, although these thresholds will not be applied clinically during the study. Expected outcomes include demonstrated feasibility of in vivo mPSD monitoring, quantitative performance metrics with confidence intervals, identification of influential factors and operational recommendations, preliminary alert thresholds with reporting templates, and a roadmap for sustainable deployment in Lévis and other centers. Scientific outputs will also be produced for dissemination across the Santé Québec network.

Interventions

• Device Brachytherapy treatment monitoring using a plastic scintillation detector
  Typical brachytherapy treatments are conducted without dose or source position monitoring in real-time. This intervention will assess the feasibility of using a scintillation detector to that end.

Primary outcome measures

• Proportion of brachytherapy treatments with successful scintillation detector-based measurement [Time frame: From the patient anesthesia at the beginning of the brachytherapy procedure to the end of brachytherapy radiation delivery on the same day.]

Eligibility criteria

Inclusion criteria

• Patients receiving prostate brachytherapy treatment, or female user receiving gynecological brachytherapy treatment for cervical cancer.

Exclusion criteria

• Patients with a Clostridium difficile infection or any other high-risk positive infection.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Other

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• Fonseca GP, Johansen JG, Smith RL, Beaulieu L, Beddar S, Kertzscher G, Verhaegen F, Tanderup K. In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice. Phys Imaging Radiat Oncol. 2020 Sep 28;16:1-11. doi: 10.1016/j.phro.2020.09.002. eCollection 2020 Oct. PMID 33458336
• Linares Rosales HM, Duguay-Drouin P, Archambault L, Beddar S, Beaulieu L. Optimization of a multipoint plastic scintillator dosimeter for high dose rate brachytherapy. Med Phys. 2019 May;46(5):2412-2421. doi: 10.1002/mp.13498. Epub 2019 Apr 2. PMID 30891803
• Linares Rosales HM, Johansen JG, Kertzscher G, Tanderup K, Beaulieu L, Beddar S. 3D source tracking and error detection in HDR using two independent scintillator dosimetry systems. Med Phys. 2021 May;48(5):2095-2107. doi: 10.1002/mp.14607. Epub 2021 Mar 28. PMID 33222208
• Therriault-Proulx F, Beddar S, Beaulieu L. On the use of a single-fiber multipoint plastic scintillation detector for 192Ir high-dose-rate brachytherapy. Med Phys. 2013 Jun;40(6):062101. doi: 10.1118/1.4803510. PMID 23718599
• Kubo HD, Glasgow GP, Pethel TD, Thomadsen BR, Williamson JF. High dose-rate brachytherapy treatment delivery: report of the AAPM Radiation Therapy Committee Task Group No. 59. Med Phys. 1998 Apr;25(4):375-403. doi: 10.1118/1.598232. PMID 9571605
• Hoopes DJ, Dicker AP, Eads NL, Ezzell GA, Fraass BA, Kwiatkowski TM, Lash K, Patton GA, Piotrowski T, Tomlinson C, Ford EC. RO-ILS: Radiation Oncology Incident Learning System: A report from the first year of experience. Pract Radiat Oncol. 2015 Sep-Oct;5(5):312-318. doi: 10.1016/j.prro.2015.06.009. Epub 2015 Jun 25. PMID 26362705
• Therriault-Proulx F, Archambault L, Beaulieu L, Beddar S. Development of a novel multi-point plastic scintillation detector with a single optical transmission line for radiation dose measurement. Phys Med Biol. 2012 Nov 7;57(21):7147-59. doi: 10.1088/0031-9155/57/21/7147. Epub 2012 Oct 12. PMID 23060069
• Beaulieu L, Beddar S. Review of plastic and liquid scintillation dosimetry for photon, electron, and proton therapy. Phys Med Biol. 2016 Oct 21;61(20):R305-R343. doi: 10.1088/0031-9155/61/20/R305. Epub 2016 Oct 3. PMID 27694714

Identifiers

NCT: NCT07580651 · 2026-1305 · 2025

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗