Brachytherapy is a form of radiotherapy where a radiation source is placed inside or next to the area requiring treatment. Brachytherapy is commonly used as an effective treatment for prostate cancer and can also be used to treat tumours in many other body sites.

Brachytherapy can be used alone or in combination with other therapies such as surgery, External Beam Radiotherapy (EBRT) and chemotherapy.

Brachytherapy involves the precise placement of short-range radiation-sources (radioisotopes) directly at the site of the cancerous tumour. These are enclosed in a protective capsule or wire which allows the ionizing radiation to escape to treat and kill surrounding tissue, but prevents the charge of radioisotope from moving or dissolving in body fluids. The capsule may be removed later, or (with some radioisotopes) it may be allowed to remain in place.

A key feature of brachytherapy is that the irradiation affects only a very localized area around the radiation sources. Exposure to radiation of healthy tissues further away from the sources is therefore reduced. In addition, if the patient moves or if there is any movement of the tumour within the body during treatment, the radiation sources retain their correct position in relation to the tumour. These characteristics of brachytherapy provide advantages over EBRT – the tumour can be treated with very high doses of localised radiation, whilst reducing the probability of unnecessary damage to surrounding healthy tissues.

A course of brachytherapy can be completed in less time than other radiotherapy techniques. This can help reduce the chance for surviving cancer cells to divide and grow in the intervals between each radiotherapy dose. Patients typically have to make fewer visits to the radiotherapy clinic compared with EBRT, and the treatment is often performed on an outpatient basis. This makes treatment accessible and convenient for many patients. These features of brachytherapy reflect that most patients are able to tolerate the brachytherapy procedure very well.

Side Effects: Like External Beam Radiation Therapy, urinary irritation is very common following brachytherapy. Obstructive symptoms including difficulty with urination are somewhat more common, however, as the prostate usually swells due to the insertion of needles into the prostate for the procedure. Less than 10 percent of men will experience complete urinary obstruction within several weeks of the procedure requiring use of a catheter. Usually this problem disappears within weeks as the swelling subsides. Since the radioactive seeds are placed directly into the prostate, short-term bowel side effects are also relatively uncommon. However, as the front part of the rectum lies close to the prostate, over time bowel side effects similar to those of EBRT may occur. As with other radiation treatments, erectile dysfunction may occur.

http://en.wikipedia.org/wiki/Brachytherapy