Brachytherapy optimization using radiobiological-based planning for high dose rate and permanent implants for prostate cancer treatment

We discuss an improvement in brachytherapy—a prostate cancer treatment method that directly places radioactive seeds inside target cancerous regions—by optimizing the current standard for delivering dose. Currently, the seeds’ spatiotemporal placement is determined by optimizing the dose based on a set of physical, user-defined constraints. One particular approach is the “inverse planning” algorithms that allow for tightly fit isodose lines around the target volumes in order to reduce dose to the patient’s organs at risk. However, these dose distributions are typically computed assuming the same biological response to radiation for different types of tissues. In our work, we consider radiobiological parameters to account for the differences in the individual sensitivities and responses to radiation for tissues surrounding the target. Among the benefits are a more accurate toxicity rate and more coverage to target regions for planning high-dose-rate treatments as well as permanent implants.