Radiation Therapy and Cancer Treatment
Radiation therapy is also called radiotherapy or therapeutic radiology. Using it to treat cancer is called radiation oncology.
Radiation therapy uses high-energy X-rays, gamma rays, or charged particles to kill cancer cells. Like surgery, it can be used in many ways depending on the type of cancer and where it is in the body. Certain levels of radiation kill cancer cells or keep them from growing or reproducing.
This treatment may be used to cure cancer, help control the disease, or help relieve symptoms it's causing.
Most radiation treatments come from a large machine that doesn't touch you and won't make you radioactive. Less often, a source of radiation may be put right into your body. Talk with your healthcare provider about any safety measures you need to take when getting radiation therapy.
What are the different types of radiation therapy?
Radiation therapy is given through different ways. The way you get it depends on the type of cancer, where it is in your body, your overall health, and your preferences. Radiation therapy is often used with other treatments, like chemotherapy or surgery. Different types of radiation therapy include:
External radiation (external beam therapy). A large machine points the radiation beams through your skin and right at the tumor. The beams are often aimed at the tumor from many different angles. A radiation therapist controls the machine. Since radiation can also affect nearby normal cells, special shields may be made to protect the tissue near the treatment area. Most of the time, treatment is done 5 days a week for many weeks. Radiation treatments don't hurt. They usually last only a few minutes.
Internal radiation (brachytherapy, implant radiation, or systemic radiation). A high dose of radiation is given inside the body. It's put as close to the cancer as possible. The radiation source may be swallowed, injected into your blood, implanted right into the tumor, or put next to the tumor through a body opening (such as the rectum). Some of the radioactive implants are called seeds or capsules. Internal radiation allows you to get a higher dose of radiation over a shorter time when compared with external radiation. Some sources of internal radiation stay in the body for a short time. Others stay in the body forever. But they lose their radiation energy over time.
In some cases, both internal and external radiation therapies are used.
Before you get radiation therapy
Radiation should be aimed as precisely at the tumor as possible. This is important for treating the tumor. It’s also important to help keep nearby normal tissues from getting too much radiation. That could lead to side effects. Each hospital may have certain protocols. But radiation therapy usually starts with these procedures:
You will first have a physical exam and a review of your medical history. Your treatment team then maps out the position you'll be in for each treatment and the exact place on your body where the radiation will be given. This is called the treatment field or port. You may also have imaging studies, such as CT scans, MRI scans, or PET scans. These may be used to help see exactly where the tumor is. This process takes a while, often a couple hours.
Sometimes, the skin over the part of your body to be treated will be marked with tiny dot tattoos. This is done to make sure radiation is given to the exact same place each time. The treatment team may also make casts, masks, molds, headrests, or other devices. These help put you in and keep you in the same position for each treatment.
Once the simulation process is done, a healthcare provider called a radiation oncologist will work with a team of experts to create your treatment plan. The plan will cover:
The type of radiation to use
How it will be given
The amount (dose) of radiation that's needed
The number of treatments you'll get