Radiation Safety and Brachytherapy Procedures

Versant Physics

Brachytherapy is a procedure that involves placing radioactive material sources inside the body, either directly inside or next to a tumor. Also known as “close” radiation, this procedure is used to treat cancer by allowing doctors to deliver higher doses of radiation via a needle or catheter to specific areas of the body.

Areas of the body commonly treated using brachytherapy include the head and neck, skin, breast, cervix, lung, prostate, uterus, and eye. Brachytherapy implants can be temporary or permanent, depending on the type of treatment needed.

Brachytherapy targets the tumor directly, which increases exposure to the cancerous cells and reduces radiation exposure to the surrounding healthy cells. Because of the targeted nature of brachytherapy, it is best used for cancers that have not metastasized. It is considered as effective as—and sometimes used in conjunction with—external beam therapy.

Types of Brachytherapy

There are three types of brachytherapy:

  • High-dose rate (HDR) implants

HDR implants are inserted into the body and left in for brief sessions of 5-20 minutes before being taken out. These sessions can occur multiple times a day over a period of weeks, depending on the type of cancer being treated and the patient’s overall health. This is typically an outpatient procedure.

Radiation Risks:

HDR procedures are typically performed in a radiation therapy vault. No visitors are allowed during the treatment. Because HDR implants are temporary, a person receiving this therapy will not give off radiation once the implant is removed. Therefore, it is unnecessary for family members or visitors to take precautions after treatment.

  • Low-dose rate (LDR) implants

LDR sources are surgically implanted within or next to a tumor, where they remain in the body for 1-7 days. This procedure usually involves a hospital stay. When the treatment is finished, the doctor removes the radiation source and the catheter/applicator used to insert it.

Radiation Risks:

Radiation exposure risk to others is low with LDR implants. However, depending on the source used, radiation rates around the patient can be elevated while the source is in place. Because of this, in some cases, it is recommended that patients:

  • Limit the number of visitors during treatment
  • Limit the time spent with visitors during or between treatments
  • Limit time spent with children and pregnant women

Permanent brachytherapy is another type of LDR brachytherapy that involves inserting a needle filled with radioactive seeds into the tumor, with the help of an ultrasound or CT. These seeds are often made of metal, are roughly the size of a grain of rice, and contain radiation sources (iodine, palladium, cesium, or iridium).

The implants remain in the body permanently, however, the radiation they emit decreases over time. Eventually, almost all the radiation will go away. This type of brachytherapy is most commonly used for the treatment of prostate cancer.

Radiation Risks:

With this type of procedure, the radioactive source is not removed at the end of treatment. Therefore, it is important to initially limit time spent with pregnant women due to the low doses of radiation being emitted from the area being treated. Even after the implants have been in place for a long time, people with permanent implants can set off airport radiation sensors.

Radiation Protection

Modern brachytherapy techniques have largely eliminated the initial radiation exposure dangers that existed several decades ago. Most radioactive sources used for brachytherapy either incorporate a metallic shield within the applicator or use an isotope that emits low-energy photons that are shielded by the patient. Radiation does not travel far outside the treatment area, which means the chance of exposure to others is low.

However, there are recommended radiation safety precautions for both patients and medical professionals during a brachytherapy treatment. These may vary depending on the source and activity used for an individual implant.

  • HDR brachytherapy treatments are performed in a radiation therapy vault. The patient remains in the treatment room alone while the source is outside of its shielded housing to limit exposure to staff and members of the public.  
  • If visitors are allowed during the course of a temporary LDR treatment, they should spend no more than 30 minutes with the patient.
  • All implants are tested and sealed before they are implanted to ensure that the radioactive material inside of them does not leak. Their placement inside the body is also unlikely to change or move.

Side Effects of Brachytherapy

Because healthy tissue and organs surrounding the tumor are not as affected by the radiation treatment, most people experience fewer and less severe side effects than occur with external beam therapy.

In addition to tenderness, bleeding, or swelling in the treatment area, the side effects a patient could experience depend largely on the type of cancer and therapy being performed. Fatigue is common.

The side effects usually go away a few days after the treatment has ended. Ask your doctor or treatment team for more information on the types of side effects you may experience.