Researchers have developed a system they say may improve the ability to maximize radiation doses to cancer tissues while minimizing exposure to healthy ones. This new system, described in a study from UBC Okanagan and Duke University, may lead to improvements in dose accuracy, sensitivity, and localization during therapy.

Andrew Jirasek, UBC Okanagan physics professor and senior author of the study, explains that the solution is to make it easier to see exactly which tissues are getting a radiation dose and how much. The new system uses a specialized polymer gel to assess both the 3D location and the treatment dose. The team’s first step was to validate the spatial accuracy of the gel, known as a dosimeter. They compared the dosimeter readings with traditional radiation treatment–planning algorithms and found that the gel dosimeter was accurate in mapping the spatial location of the delivered radiation. Measurements of the radiation dose were also validated and visualized with the dosimeter. The new system also allows for direct visualization of the radiation dose immediately after therapy, which results in efficient and accurate testing.

Jirasek worked with colleagues from Duke University to take advantage of positioning systems already in place on most linear accelerators that deliver a radiation beam to the patient, which allowed for a new adjustment to be implemented without significant changes to the equipment. Next steps are to improve the process so it can move into the clinic setting.

The research was published in the International Journal of Radiation Oncology, Biology, and Physics. The article, “Delivered dose distribution visualized directly with onboard kV-CBCT: Proof of principle,” is available at www.redjournal.org/article/S0360-3016(18)34189-0/fulltext [9].