High dose rate brachytherapy now offered in Bozeman

Bozeman Deaconess Cancer Center has added a Nucletron® high dose rate (HDR) brachytherapy unit to its radiation oncology treatment program. HDR brachytherapy is used to treat certain breast and gynecologic cancers. According to David Koeplin, MD, Bozeman Deaconess Cancer Center radiation oncologist, brachytherapy is radiation delivered from the inside out. Potent, radioactive material, in the form of a rice-sized bead at the tip of a retractable wire, is inserted directly into cancerous tissue for a brief, intense, high dose. “Treating breast cancer with conventional external beam radiation with our linear accelerator can take six and a half weeks of daily treatments,” Koeplin says. “With HDR, we can complete radiation treatment in one week. And, because the treatment is so precise, less healthy tissue is harmed.” Patients can expect little discomfort and fewer side effects with HDR. In some cases, the new HDR treatment replaces external beam therapy while in others it’s given in addition to conventional external beam and, if needed, chemotherapy.

Unlike traditional prostate brachytherapy where low-dose radioactive seeds are permanently placed near the cancer, HDR brachytherapy is not an implant. Rather, HDR is delivered via a single radioactive bead. The tiny treatment bead, which is replaced every four months when it’s no longer as potent, is housed in a small robot-like machine, the Nucletron. A portal in the Nucletron delivers the treatment source wire through a hollow catheter tube to specialized plastic applicators that are attached to a surgically placed temporary balloon catheter in the tumor site cavity. Following each preplanned and image guided treatment, the source wire retracts to the Nucletron for safe storage.

“Because the irradiated target volume is smaller, we can give larger doses per day,” Koeplin explains. He says breast cancers treated with external beam therapy expose the entire breast to radiation. Not all breast cancer patients are candidates for HDR partial breast brachytherapy; those who are receive the same dose of radiation but it’s delivered only to the section of the breast cavity where cancer was found.