Brachytherapy involvers implanting a radioactive source into or near the tumor for several minutes or hours depending on the equipment used. During treatment the patient is isolated and controlled; at the end of treatment, the patient is not radioactive and can, in most cases, return home. For some kinds of tumors brachytherapy is associated with external beam radiotherapy.
The treatment is accurate and flexible and the brachytherapy implant precisely reflects the treatment plan given its short duration and the external link to the 'applicator'.

PERMANENT IMPLANT
Brachytherapy in localized prostate cancer
'Permanent' brachytherapy involves implanting tiny 'seeds' that contain radioactive palladium 103/Pd or iodine 125/I-125 in the prostate gland. The procedure is minimally invasive is takes about 90 minutes to complete.
The seeds are contained in thin needles that are passed, under ecographic guidance, into the prostate gland through the skin between the scrotum and anus (perineum). This usually performed under sedation or local anesthesia. The ecographic probe and the needles are extracted after the procedure.
Each seed continuously releases a small amount of radiation to a limited part of the prostatic tissue.

Consequently, high doses of radiation can be directed at the tumor without damaging the surrounding healthy tissue. The radioactivity of the seeds slowly decays in the months after implantation, and can remain in position without affecting the patient in any way.
The percent of cures in the first series patients with localized prostate carcinoma treated12 years ago with this technique was similar to that obtained with surgery (radical prostatectomy) and above that obtained with conventional external beam radiotherapy.
Brachytherapy can be proposed as an alternative to radical prostatectomy in patients affected by clinically localized prostate adenocarcinoma. Depending on the patient's clinical, physical and psychological characteristics, the physician will suggest the most appropriate treatment (brachytherapy, surgery or other forms of treatment of prostate cancer).

TEMPORARY IMPLANT
Also 'temporary' brachytherapy involves targeting high doses of radiation to well-defined areas while sparing healthy surrounding tissue. In this case, the radioactive source is implanted in the prostate gland with thin catheters. The patient undergoes transrectal ultrasound to determine the number and position of the catheters through which the radioactive seeds will be implanted. The catheters are then passed, under ecographic guidance, into the prostate gland through the skin between the scrotum and anus (perineum), under sedation or local anesthesia. When the seeds have been implanted, the patient undergoes a treatment-planning prostate CT. Because the treatment plan is decided after implantation, treatment can be optimized in case of misplacement of catheters. At present, only HDR iridium-192 is used for temporary brachytherapy.
Radiation treatment is administered in a shielded bunker to limit the operator's exposure to radiations. In the bunker, an afterloading device (teleloading the radioactive sources) allows the insertion of the same seed (with reduced costs) in the planned position, and the time it remains is determined with dedicated software. The procedure can be done in day surgery. The number of sessions varies from one to eight at weekly intervals, and the procedure can be associated with a cycle of external conformational radiotherapy.
The higher energy of iridium-92 compared with radiation sources used for permanent implants, provides a wider dosimetric cover, which is desirable in the case of capsular micro-infiltrations.