Feasibility study of navigated endoscopy for the placement of high dose rate brachytherapy applicators in the esophagus and lung.

PURPOSE: To evaluate the electromagnetic (EM) tracking of endoscopes and applicators as a method of positioning a high dose rate (HDR) luminal applicator. METHOD: An anatomical phantom consisting of a rigid trachea and flexible esophagus was used to compare applicator placement measurements using EM tracking vs the traditional method using two-dimensional (2D) fluoroscopy and surface skin markers. The phantom included a tumor in the esophagus and several pairs of optically visible points inside the lumen that were used to simulate proximal and distal ends of tumors of varying lengths. The esophagus tumor and lung points were visible on a computed tomography (CT) image of the phantom, which was used as ground truth for the measurements. The EM tracking system was registered to the CT image using fiducial markers. A flexible endoscope was tracked using the EM system and the locations of the proximal and distal ends of the tumor identified and this position recorded. An EM-tracked applicator was then inserted and positioned relative to the tumor markings. The applicator path was mapped using the EM tracking. The gross tumor length (GTL) and the distance between the first dwell position and distal edge of tumor (offset) were measured using the EM tracking and 2D fluoroscopy methods and compared to the same measurements on the CT image. RESULTS: The errors in GTL using EM tracking were on average -0.5 ± 1.7 mm and 0.7 ± 3.6 mm for esophagus and lung measurements, similar to errors measured using the 2D fluoroscopy method of -0.9 ± 1.2 mm and 3.4 ± 4.4 mm. Offset measurements were slightly larger while using EM tracking relative to the fluoroscopy method but these were not statistically significant. CONCLUSIONS: Electromagnetic tracking for placement of lumen applicators is feasible and accurate. Tracking of the endoscope that is used to identify the proximal and distal ends of the tumor and of the applicator during insertion generates accurate three-dimensional measurements of the applicator path, GTL and offset. Guiding the placement of intraluminal applicators using EM navigation is potentially attractive for cases with complex insertions, such as those with nonlinear paths or multiple applicator insertions.

Brachytherapy patient safety events in an academic radiation medicine program.

PURPOSE: To describe the incidence and type of brachytherapy patient safety events over 10 years in an academic brachytherapy program. METHODS AND MATERIALS: Brachytherapy patient safety events reported between January 2007 and August 2016 were retrieved from the incident reporting system and reclassified using the recently developed National System for Incident Reporting in Radiation Treatment taxonomy. A multi-incident analysis was conducted to identify common themes and key learning points. RESULTS: During the study period, 3095 patients received 4967 brachytherapy fractions. An additional 179 patients had MR-guided prostate biopsies without treatment as part of an interventional research program. A total of 94 brachytherapy- or biopsy-related safety events (incidents, near misses, or programmatic hazards) were identified, corresponding to a rate of 2.8% of brachytherapy patients, 1.7% of brachytherapy fractions, and 3.4% of patients undergoing MR-guided prostate biopsy. Fifty-one (54%) events were classified as actual incidents, 29 (31%) as near misses, and 14 (15%) as programmatic hazards. Two events were associated with moderate acute medical harm or dosimetric severity, and two were associated with high dosimetric severity. Multi-incident analysis identified five high-risk activities or clinical scenarios as follows: (1) uncommon, low-volume or newly implemented brachytherapy procedures, (2) real-time MR-guided brachytherapy or biopsy procedures, (3) use of in-house devices or software, (4) manual data entry, and (5) patient scheduling and handoffs. CONCLUSIONS: Brachytherapy is a safe treatment and associated with a low rate of patient safety events. Effective incident management is a key element of continuous quality improvement and patient safety in brachytherapy.

Use of hydrogel spacer for improved rectal dose-sparing in patients undergoing radical radiotherapy for localized prostate cancer: First Canadian experience.

We describe the initial experience using a hydrogel spacer (SpaceOAR) to separate the prostate-rectum interspace in patients planned to undergo radical hypofractionated, image-guided, intensity-modulated radiotherapy (IG-IMRT). We depict and discuss the impact of SpaceOAR in the context of hypofractionated IG-IMRT, and the particular considerations for its applications in the Canadian setting.