Brachytherapy: Understanding Internal Radiation Therapy

Brachytherapy is a type of cancer treatment. It uses a small source of radiation placed in or next to a tumor to kill cancer cells. You might also hear it called internal radiation therapy.

Because the radiation is placed close to the cancer, it mainly targets the tumor and nearby tissue. This helps limit radiation to the rest of your body.

What is brachytherapy?

Radiation therapy uses high-energy X-rays or particles to damage the DNA of cancer cells so they can no longer grow. There are two broad ways to deliver it:

External-beam radiation therapy (EBRT): A machine outside your body aims radiation at the tumor.
Internal radiation therapy (brachytherapy): A tiny sealed source of radiation is placed inside your body, in or right next to the cancer.

Some people have brachytherapy alone. Others have it along with EBRT or with other treatments. Your oncology team will explain why a certain plan was chosen for you.

Types of brachytherapy

Low-dose rate (LDR): Small “seeds” or capsules are placed into the tumor area and left there. They release radiation over weeks to months. After that, they no longer give off radiation. The seeds usually stay in your body permanently, but they are inactive.
High-dose rate (HDR): A higher-strength source of radiation is placed through a thin tube (catheter or applicator) for a short time—often minutes—then removed. This may be repeated over several sessions (called fractions) across days or weeks.

Which cancers can be treated?

Brachytherapy is used for many cancers, often including:

Prostate
Cervix
Lining of the uterus (endometrium)
Vagina
Some head and neck, breast, skin, and other select tumors

Your team considers tumor size, location, and your overall health when deciding if brachytherapy is appropriate.

How is brachytherapy planned?

Careful planning helps deliver the right dose to the right place.

Consult and exam: You meet with a radiation oncologist to review your history and goals of care.
Imaging: CT, MRI, ultrasound, or X-rays help map the tumor and nearby organs.
Treatment plan: Specialists calculate how much radiation you need and where to place the source.
Safety review: Your team explains benefits, possible risks, and how to protect others.

What happens during treatment?

Your experience depends on the cancer type and whether you have LDR or HDR. In general:

Anesthesia or medicines: You may get medicines to make you relaxed, numb, or asleep. This depends on the location of treatment and your health.
Applicator or tube placement: The doctor places a thin tube or special applicator into the tumor area. Imaging helps guide placement.
Delivery of radiation: The radiation source is passed through the tube into the treatment area.

After placement, what happens next differs by type:

LDR: The tube is removed and the tiny seeds stay in place. Many people go home the same day. The seeds give off low levels of radiation for a limited time.
HDR: The source goes in for a short session, then is removed. You may have several sessions. The tube may stay in between sessions or be placed each time. Most people go home after each treatment.

Your team will tell you how long each visit will take, how many sessions you will need, and what to expect for recovery.

Safety around others

Your radiation team will give you personalized safety instructions.

HDR: Because the source is removed after each session, you are not radioactive between treatments.
LDR seeds: You may give off low levels of radiation for a short time. Your team may advise you to limit long, close contact with others for a period, especially with young children and people who are pregnant.

General tips to discuss with your team:

Follow any time and distance limits they recommend for close contact.
Ask when it is safe to lift children into your lap or sleep next to someone.
Carry any wallet card they provide. Rarely, seeds can set off security scanners.
Ask before having certain scans or medical procedures soon after placement.

Common side effects

Side effects depend on the body area treated, dose, and schedule. Your team will review what is most likely for you.

General: Tiredness, mild discomfort, swelling, or bruising near where the tube or applicator was placed.
Skin or entry site: Redness, soreness, or irritation where the tube went in.
Pelvis (prostate, cervix, uterus, vagina): Urinary urgency or frequency, burning with urination, mild blood in urine, bowel changes (loose stools, more frequent stools), pelvic pressure, spotting or discharge.
Head and neck or skin areas: Local soreness, swelling, or temporary changes in taste or saliva if nearby tissues are affected.

Most side effects are temporary. Your team can suggest ways to manage them, such as skin care, sitz baths, or medicines for bladder or bowel symptoms. Always check before using over-the-counter products or supplements.

Self-care during treatment

Follow your schedule for visits, imaging, and any lab tests.
Report new or worsening symptoms promptly.
Eat enough calories and protein to support healing. Small, frequent meals can help.
Drink fluids unless your team gives you a different plan.
Prioritize sleep and light activity, like short walks, to reduce fatigue.
Ask about sexual activity, fertility, and contraception during and after treatment.

Questions to ask your care team

What is the goal of brachytherapy in my case?
Will I also have external-beam radiation or other treatments?
How many sessions will I need, and how long is each one?
What side effects are most likely for the area being treated?
What precautions should I take at home, and for how long?
When can I return to work, exercise, and sexual activity?
Who do I call if I have problems after hours?

Key takeaways

Brachytherapy delivers radiation from the inside to treat cancer with precision.
LDR uses permanent seeds that become inactive; HDR uses a temporary source removed after each session.
Side effects depend on where you are treated and your dose. Most can be managed.
Your team will guide you on safety, symptoms to watch, and follow-up care. Do not hesitate to reach out with questions.

Helpful resources and references

Last reviewed: 2025-11-21