A quality assurance device for measuring afterloader performance and transit dose for nasobiliary high-dose-rate brachytherapy

Technique for the administration of high-dose-rate brachytherapy to the bile duct using a nasobiliary catheter

“…The relative lack of centers that perform HDR biliary brachytherapy could be due to lack of awareness of, training in, or concern over the technical challenges associated with the technique. While a disadvantage of nasobiliary HDR brachytherapy is the risk that the afterloader device is incapable of advancing the source wire into the treatment site, our results suggest that this risk is relatively low (!1%) and may be mitigated with an extensive QA program to monitor the performance of the afterloader and ancillary equipment (14). The single patient in which the HDR afterloader was physically unable to extend the source wire into the treatment site was observed to have a catheter path (single catheter) that curved sharply at the junction of the bile duct and the duodenum, and the afterloader was unable to extend the source wire past the junction.…”

“…Periodic QA using a quasianatomical device has been used to test the afterloader's capability of traversing through the nasal, stomach, duodenum, and bile duct (14). The QA device ensures that the afterloader has not changed substantially after radioactive source exchange, and that the service engineer has tuned the device such that the radioactive source wire has slightly greater capability to extend than the nonradioactive ''dummy'' wire.…”

“…The QA device ensures that the afterloader has not changed substantially after radioactive source exchange, and that the service engineer has tuned the device such that the radioactive source wire has slightly greater capability to extend than the nonradioactive ''dummy'' wire. This helps to avoid a situation in which the dummy wire can reach the treatment position, whereas the active source cannot, thereby preventing the accumulation of unnecessary transit dose (14). The device also ensures that each new lot of 4.7-Fr intraluminal catheters performs similarly to previous lots.…”

Technical note: Analysis of brachytherapy source movement by high‐speed camera

“…Many investigators have evaluated the transit dose based on measurements such as thermoluminescent dosimeter (TLD), 3 films, 4,5 ionization chambers, 6,7 video camera, 7,8 optical fiber detectors, 9 diodes, 10 and dosimetry impact by the Monte Carlo method 11 and analytical approaches. 12 However, previous investigations using a high-speed camera focused on the interdwell transit speed and transit dose components.…”