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Brachytherapy is a form of radiation therapy where small radioactive sources—such as seeds, pellets, ribbons, wires, needles, balloons, or capsules—are placed directly inside or very close to a tumor. The word "brachy" comes from a Greek word meaning "short distance," reflecting how the radiation is delivered right at the cancer site instead of from outside the body. This approach allows doctors to target cancer cells more precisely while limiting exposure to nearby healthy tissues.
The radioactive sources may be inserted using flexible tubes called catheters or larger devices known as applicators. Depending on the type of cancer and treatment plan, these sources can stay in place for a few minutes, several days, or permanently.
Brachytherapy offers a way to deliver high doses of radiation directly to the tumor while reducing radiation exposure to surrounding healthy tissues. This focused treatment can help improve effectiveness and reduce side effects compared to some other radiation methods. Because the radioactive sources are placed inside or near the tumor, they stay in the correct position even if the patient moves or if the tumor shifts slightly during treatment.
This treatment is often used for cancers such as prostate, cervical, breast, head and neck, and some others. It may be used alone or combined with other treatments like surgery, chemotherapy, or external beam radiation therapy. Brachytherapy can sometimes shorten overall treatment time and reduce the number of visits needed compared to external radiation.
Patients may hear about different types of brachytherapy, including low-dose-rate (LDR) brachytherapy, where radioactive seeds may remain in the body permanently or temporarily, and high-dose-rate (HDR) brachytherapy, which uses temporary sources that deliver radiation in short bursts during each session. Another type, pulsed-dose-rate (PDR) brachytherapy, delivers repeated short pulses to mimic LDR effects.
The procedure to place the radioactive material is carefully planned and performed by a specialized team that may include radiation oncologists, medical physicists, dosimetrists, radiation therapists, surgeons, nurses, and radiation safety experts. Patients might be told about how the implant is placed, how long treatment lasts, and what side effects to expect. Common side effects depend on the area treated but often include fatigue and localized skin changes or discomfort.
You may encounter the term in your treatment plan, medical reports, clinical trial descriptions, or when discussing radiation options with your care team. It is sometimes called implant radiation therapy or radiation brachytherapy. Specific types of brachytherapy, like balloon catheter radiation (also known as MammoSite), may be mentioned after breast cancer surgery to deliver radiation directly to the area where the tumor was removed.
Hearing the term brachytherapy does not by itself indicate a certain type or stage of cancer. It also does not guarantee a specific outcome, as treatment plans are personalized based on many factors including tumor size, location, and overall health. Brachytherapy is one of several ways to deliver radiation therapy and may not be suitable or recommended for every patient.
If brachytherapy is part of your treatment discussion, consider asking how it compares to other radiation options, what to expect during and after the procedure, possible side effects, and how it fits into your overall care plan. Understanding these details can help you feel more informed and prepared.
This information is meant to educate and support patients and caregivers but cannot replace personalized medical advice. Treatment choices depend on many factors unique to each person’s cancer and health. Always discuss your specific situation and treatment options with your healthcare providers. If you are considering or scheduled for brachytherapy, your next step is to talk openly with your cancer care team about what the treatment involves, how it may help you, and any concerns you have.
Public source information used for this glossary entry includes: