Brachytherapy is internal radiation treatment given by placing radioactive material directly into a tumor or close to it. For prostate cancer, brachytherapy may involve the permanent placement of radioactive "seeds" into the prostate gland or the temporary placement of a high-energy radioactive source into the prostate gland.
Low Dose Rate (LDR) Brachytherapy delivers low dose rate (LDR) radiation to tumor areas. It involves the implantation of tiny radioactive "seeds" into the prostate gland and is also known as an interstitial implant. The specified radiation emitted by the radioactive "seeds" kills the tumor cells. This procedure can be combined with external-beam radiation to increase the radiation dose while sparing normal tissues from damage.
Complex three-dimensional treatment planning is done prior to implantation using transrectal ultrasound (TRUS) which creates a three-dimensional map of the prostate. The computer then calculates the volume of the gland, and the number of radioactive "seeds" that are needed along with the specific location where they should be placed.
The procedure, performed on an outpatient basis, takes 45 to 60 minutes and is done under local (spinal) anesthesia. The radioactive seeds are placed by special needles that are inserted through the perineum (the area of skin that is located below the anus and extends to the base of the testicles) into the prostate. The seeds contain a radioactive isotope (usually Palladium 103 or Iodine 125), which emits radiation for about 3 months before becoming inert. Brachytherapy patients are discharged the same day and can resume normal activity within two days.
High Dose Rate (HDR) Brachytherapy is a completely different process for delivering radiation therapy that allows high doses of radiation to be delivered to tumors. It uses one very small high-intensity radiation source on the end of a thin cable that is inserted temporarily. With image guidance, several thin, hollow needles are implanted into the prostate. Delivery of HDR radiation is administered using a state-of-the-art, automated, remote after-loading device that places the radioactive source. It moves up and down each needle and rests for a calculated period of time at various positions within each needle, delivering radiation). This type of brachytherapy leaves no permanent radiation in the patient. The radioactive implants are temporary, lasting anywhere from minutes to hours, and are given in separate sessions approximately 6 hours apart. When prescribed radiation is delivered in multiple doses it is called fractionated therapy.
