Report on the World Congress of Brachytherapy 2024
A focus point in the physics track at the World Congress of Brachytherapy 2024 was patient safety. Almost two full sessions were dedicated to it and to treatment verification. On the first day of the congress, Associate Professor Matha McKee, Wake Forest University, USA, Associate Prof Jacob Johansen, Aarhus University, Denmark and Dr Mauro Carrara, International Atomic Energy Agency (IAEA), Austria, presented the efforts that are made to keep patients safe in the USA, Europe and from the IAEA perspective, respectively in the session called “Regulations and beyond: How to keep patients safe”. The speakers described the demands on, for instance, dosimetry in brachytherapy as set out in national and international regulations, as well as the importance of further development of dosimetry methods. Associate Prof McKee also showed the importance of incident-based learning and how registries play an important role in this effort. On the third day, Dr Joel Poder, St. George Hospital Cancer Care Centre, Australia and Prof Luc Beaulieu, Université Laval, Canada presented on the current clinical use of in-vivo dosimetry and electromagnetic tracking of catheters for treatment verification.
Catheter tracking was also well-represented in the other physics sessions. In one study, the manufacturer-specified dwell positions were compared with electromagnetically tracked positions for eight tandem-ring applicators. The study showed deviations of around 3mm at the tips of the applicators. Another study presented the results from a commissioning of two remote afterloaders. Here the positional accuracy of the afterloaders was validated through the use of radiochromic film. The measurements showed deviations >1.5mm for some configurations. A novel tracking method was also explained; this method involved the use of an infrared camera placed on a mobile cone beam CT scanner. Finally, electromagnetic tracking was used to fuse MR and ultrasound images to enable live tracking during catheter insertion.
Two new dosimetry techniques for quality assurance were presented. The 3D dose distribution from low-dose-rate seeds was measured through the use of a 3D gel phantom, while the depth dose and absolute dose of 106Ru eye-plaques were determined through the use of alanine pellets and a MicroSilicon detector respectively. The measured eye-plaque doses were generally lower than the vendor specifications although within the vendor-reported uncertainties. Methods for the performance of in-vivo dosimetry during brachytherapy were presented in two posters. In both cases, scintillator-based detectors were used to perform time-resolved in-vivo dosimetry. In one of these studies, in-vivo dosimetry had been used for prostate, while the other showed results from cervical brachytherapy.
Finally, the IAEA dosimetry code of practice for secondary standard laboratories (technical report series 492) was presented by Prof Marc Rivard, Rhode Island Hospital, USA. As part of the presentation, the various correction factors that are required during performance of absolute dosimetry were discussed.
All in all, the presentations at the Congress showed ongoing interest in treatment validation and quality assurance, and that the field is developing. The need for continuous performance of dosimetry and quality assurance was also highlighted by the interesting findings from clinical practice.
