Radiation Therapy

How does cancer radiation work?

Normal cells grow and divide to form new cells. Cancer cells grow and divide faster than most normal cells. Radiation works by making small breaks in the DNA inside cells as they are dividing. This makes cancer cells a lot more vulnerable to radiation than normal cells, as they divide more often. These breaks in the DNA keep cancer cells from growing and dividing, causing them to die.

The goal of radiation therapy is to destroy cancer cells and/or slow tumor growth without harming nearby healthy tissue.

What are the types of radiation?

The most common type of radiation is called external-beam radiation therapy, which is given from a machine located outside the body. Types of external-beam radiation therapy include proton therapy, 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and stereotactic radiation therapy (SRS or SBRT). Radiation can also be given using implants – this is called internal radiation therapy or brachytherapy.

When is radiation used?

Radiation can be used by itself to make the cancer shrink or completely go away. In some cases, chemotherapy may be given first. For other cancers, radiation may be used before surgery to shrink the tumor or after surgery to help keep cancer from coming back.

Who gives radiation therapy treatments?

• Radiation oncologist: This doctor is specially trained to treat cancer with radiation. This person oversees your radiation treatment plan.
• Dosimetrist: This person plans where the radiation beams go to ensure that the most effective and safe dose of radiation.
• Radiation therapist or radiation therapy technologist: This person operates the radiation equipment and positions you for each treatment.
• Radiation physicist: This is a person who makes sure the radiation equipment is working as it should and that it gives you the exact dose prescribed by your radiation oncologist.
• Radiation therapy nurse: This nurse has special training in cancer treatment and can give you information about radiation and managing side effects.

What happens during your CT planning scan?

If you need radiation therapy, your first radiation therapy session is called a simulation and does not involve actual treatment. During this visit, your radiation team will position your body and then take a scan with a CT-scanner. At this time a technique may be used to note your position, such as permanent tattoos or temporary skin marks. These marks or technology are used to help the radiation team set up you up correctly for every treatment. Your treatment will begin a few days after simulation.

How long is radiation treatment?

Treatment is usually given once a day for between one day and eight weeks. Treatments typically take on average between 5 and 30 minutes. This depends on the complexity of the individual treatment plan. Most of the time in the treatment room will be spent making sure you are in the correct position for treatment. The beam on time is usually less than a minute each time. You will most likely have radiation delivered from multiple different machine angles. Many clinics now use AlignRT to assist them in ensuring you are in the right position.

What is hypofractionation?

Hypofractionation is an advanced treatment technique that is becoming a standard of care for lung, breast, and prostate cancer patients. Using hypofractionation, or hypofractionated radiation therapy, higher doses of radiation are delivered over a shorter timeframe, so patients can complete their course of radiation therapy much faster than conventional treatments.

Some patients are eligible for extreme hypofractionation or SBRT (stereotactic body radiation therapy), which, when appropriate, can shave weeks off the traditional treatment length. Because each cancer type requires a different approach, each patient’s treatment plan is customized to their unique needs and treatment goals.

What are the potential radiation side effects?

The side effects of radiation therapy vary and depend on the type and location of cancer, treatment dose, and your overall health. Side effects may include fatigue, skin reactions, upset stomach, and loose bowel movements. These often begin during the second or third week of treatment and may last for several weeks after the final radiation. Most side effects go away after treatment, although some long-term side effects may occur months after or years after treatment. Be sure to discuss the potential side effects with your doctors. More Side Effect Information