What is brachytherapy?

Brachytherapy refers to radiation treatments performed at short distances. (The prefix “brachy” comes from the Greek word for “short.”) This typically involves placing small radioactive sources inside or next to the patient’s body, usually to treat cancer. Brachytherapy sources are usually small pellets of radioactive material, though in some cases small electronic x-ray devices may be used.

The main advantage of brachytherapy is that most of the radiation dose is deposited close to the radiation source. This makes it possible to deliver high radiation doses to a tumor while keeping unwanted doses to surrounding healthy tissues low. It also results in short treatment times, which can make the radiation treatment more effective as well as reduce the amount of time the patient spends in the clinic. For many patients, brachytherapy is  an effective and convenient treatment option. For some cancers, such as advanced gynecologic tumors, patient long-term survival is highest when external-beam radiation therapy and brachytherapy are both used, rather than external-beam therapy alone.

Brachytherapy is most commonly used to treat cancers of the prostate, breast, cervix, endometrium, skin, and eye. Less commonly, brachytherapy may be used to treat sites like the esophagus or lung. Brachytherapy may be used alone or together with external-beam therapy to increase the dose to a disease site.

Prostate, breast, and advanced gynecologic cancers may be treated using “interstitial” brachytherapy, in which radiation sources are placed inside the targeted tissues. This is accomplished by inserting hollow needles or similar devices into the affected tissue and then a passing radioactive source or sources through those devices. Prostate brachytherapy may involve permanent implantation of low-dose-rate (LDR) radioactive seeds or temporary application of a high-dose-rate (HDR) radioactive source.

Skin and eye cancers may be treated using “contact” brachytherapy, in which radiation sources are placed next to the targeted tissue. For skin treatments, the sources are placed against the body. Gynecological treatments may use “intracavitary” brachytherapy, where sources are passed into the vagina, cervix, and uterus.

For most cancers treated with brachytherapy, the procedure is more invasive than external beam radiotherapy, though there are a few exceptions (e.g., skin brachytherapy). In all cases, the radioactive sources used in brachytherapy are placed in a manner such that the delivered dose conforms to the shape of the targeted tumor, and radiation dose to other areas of the body is minimized.