Low dose rate (LDR) brachytherapy
Radioactive sources have been used in medicine since the discovery of radiation. Originally, because of technical difficulties in producing high-intensity sources, most brachytherapy involved low intensity sources, or what’s known today as low dose rate brachytherapy.
This therapy is usually performed in a hospital setting. In an operating room, radioactive “seeds” are surgically implanted in or near a tumor, allowing a higher dose of radiation to be delivered to the tumor, and keeping the dose to the normal surrounding tissues to a minimum. LDR brachytherapy is used for prostate cancer treatment, where it is often called a prostate seed implant, as well as several gynecologic tumor settings.
Minneapolis Radiation Oncology physicians pioneered the use of brachytherapy for prostate cancer in the Upper Midwest. The first treatment in the region was performed by MRO physician Dr. Doug Olson in 1988.
Prostate brachytherapy is performed in a specially-equipped operating room by a radiation oncologist and an urologist while a patient is asleep under general anesthesia. Working closely together, the team uses ultrasound guidance to place long thin metal tubes into the prostate, through which 70 to 120 tiny radioactive seeds are implanted. The seeds are about the thickness of a pencil lead and just over 1/8 inch long. The procedure typically takes one hour, and the patient is usually discharged later that day.
Although the internal seeds emit low-energy radiation with only trace amounts of radiation outside the patient’s body, all facilities performing brachytherapy for prostate cancer recommend patients avoid close contact with children and pregnant women for a short time following seed placement. After approximately 6 months, the seeds will be essentially inactive. They can be safely left in place indefinitely.
High dose rate (HDR) brachytherapy
Devices called high-dose rate (HDR) remote after-loading machines allow radiation oncologists to complete the brachytherapy procedure in just 10 to 20 minutes. In HDR brachytherapy, powerful radioactive sources travel through small tubes to the tumor for the amount of time prescribed by your MRO radiation oncologist. Depending on the area treated, you may receive several HDR treatments over a number of days. This treatment is often used for gynecologic cancers.
Once your treatment is finished, your MRO oncologist will remove the radiation source and the catheter or applicator.