To speak with Dr. Daniel Miller or Dr. Douglas Holt about cancer care, please call (208) 227-2700.
The Idaho Cancer Center at EIRMC is the only facility in the region offering advanced High Dose Rate (HDR) brachytherapy, and the only radiation oncology facility in Idaho that is accredited by the American College of Radiology.
In contrast, Low Dose Rate (LDR) brachytherapy is widely performed in our region. Until recently, it was once the only type of brachytherapy available.
However, High Dose Rate (HDR) brachytherapy provides a more precise treatment in only a few minutes, while sparing healthy tissue from radiation.
Limitations of Low Dose Rate Brachytherapy
Limited ability to adapt the radiation to fit the tumor
Once permanent seeds are inserted into the tissue, their position and the amount of radiation they emit cannot be changed.
Longer treatment times
During LDR, hundreds of tiny seeds are permanently implanted, releasing radiation at a low dose over several weeks or months. The seeds remain in the tumor permanently. LDR is typically a one-time treatment as the seeds are permanent.
For prostate patients, during the weeks and months it takes the permanent seeds to deliver the prescribed dose, the seeds can move around inside the prostate and even drift entirely out of the prostate and into the bladder, urethra, rectum, pelvic cavity and lungs.
Gynecologic cases using LDR require a two-day hospital stay. An applicator inside the patient contains the radioactive sources, and any movement of the applicator results in uncertain doses to the tumor and nearby structures. Thus, the patient must remain in bed as motionless as possible.
Radioactive During Treatments
During LDR treatment, the patient is radioactive for 6 months. Patients must follow radiation protection precautions for 3 months following implantation; this includes avoiding children and women of childbearing age.
Why High Dose Rate (HDR) Brachytherapy?
In contrast, the more advanced HDR brachytherapy removes these limitations.
Greater ability to conform the radiation to the unique tumor
The HDR system uses a single, small, (1mm x 3 mm) highly radioactive source of Iridium-192 that is attached to the end of a thin, flexible cable. The radioactive source is inside a device called an afterloader. The computer–guided afterloader leads the source into the treatment catheters or applicator already placed in the patient. The treatments are planning specifically based on the final catheter location after the patient is transferred back from surgery, allowing the physician to be more specific in planning.
The source moves through each catheter in 5mm steps, called “dwell positions.” The dwell positions that the source stops at, and the length of time it dwells there, determines the radiation dose and distribution. This allows for an unlimited choice of source strengths, unlike with LDR.
Shorter treatment times
HDR brachytherapy can be performed in 3 to 10 treatments, depending on the type of cancer being treated.
No concerns about radioactive exposure to family
The radioactive source retracts back into the afterloader once the treatment is complete. The patient is no longer radioactive, eliminating any radiation exposure for family
More precise dosing
The final doses are known before any radiation treatment begins. Since the patient and implant position remain the same as when the treatment plan is devised, doses are more accurate.