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Radiation Treatment

Radiation therapy is a cancer treatment that uses high-energy x-rays to kill cancer. You have probably seen an x-ray of your teeth or another part of your body. At high doses, many times greater than those used for x-ray exams, radiation can kill cancer cells and shrink tumors. 

Radiation works because cancer cells reproduce faster than normal cells in the body. Radiation targets these rapidly dividing cells. Radiation reacts with the water in the cells, and this reaction damages the DNA or genetic material in the cell that controls cell growth. During this process, normal cells are also affected, but they can repair themselves more effectively and continue to grow. Cancer cells cannot repair themselves as easily and die.

Radiation therapy has undergone major advances in recent years. The use of computers and sophisticated equipment and a new understanding of how cancer cells work have made radiation safer than ever. Doctors are extremely careful to limit damage to healthy tissue by:

  • Precisely targeting radiation beams directly at the cancerous area
  • Dividing treatments into several small sessions called fractions
  • Making sure equipment is in top working order
  • Using the minimal effective dose

Patients usually receive external beam therapy for five days in a row, with rest over the weekend. Receiving small frequent doses with brief rests limits damage to healthy cells, while effectively destroying cancer cells.

Our doctors use several types of radiation therapy:

  • External Beam Radiation: In this type of treatment, the radiation comes from a large machine outside the body. At Teton Cancer Institute, we use a linear accelerator, manufactured by Varian to produce photons and electrons for treatment. There is no active source, and the radiation is manufactured using electricity much like an x-ray. This machine delivers radiation treatments with pin-point accuracy.
  • Internal radiation (Also called Brachytherapy): The radiation comes from radioactive material placed in seeds, needles or thin plastic tubes that are put in or near the tumor. Patients usually stay in the hospital for this treatment. The radioactive source can either be implanted permanently, or placed in for a certain amount of time and then removed.
  • Systemic Radiation: Comes from a liquid or capsule containing radioactive material that travels throughout the body. You swallow the liquid or capsules or receive an injection. This type of radiation therapy can be used to treat cancer or control pain from cancer that has spread to the bone. At Teton Cancer Institute, we are extremely happy that we can offer Xofigo®, which is a radiopharmaceutical systemic radiation in which a radioactive isotope is administered to help with pain from bony metastases from prostate cancer.

Radiation therapy can be used:

  • As a primary treatment to destroy cancer cells
  • In combination with other treatments to stop the growth of cancer cells 
  • Before another treatment, such as surgery, to shrink a tumor
  • After another treatment to stop the growth of any remaining cancer cells
  • To relieve symptoms of advanced cancer

The type of radiation therapy used depends on many factors including The type of cancer, the size of the tumor, and the tumor’s location in the body, how close the cancer is to normal tissues that are sensitive to radiation and how far into the body the radiation needs to travel.

Depending on your individual needs, you may receive radiation therapy alone or in combination with other treatment modalities such as; surgery, chemotherapy, hormone therapy and/or immunotherapy. Throughout your treatment, your radiation oncologist will monitor the effectiveness of the radiation therapy and modify your treatment plan accordingly.

After careful consultation with you and your physicians, you decide that external beam radiation is appropriate for your cancer treatments; you will undergo a process called simulation (also referred to as mapping). Using CT scans, computers, and precise measurements, this detailed process maps out the exact location where the radiation will be targeted.

When you come in for a CT simulation, you will have a CT scan of the area of your body to be treated with radiation. Every effort will be made to ensure that you are as comfortable as possible for your simulation, as the goal is to position you, in the same way, every day during your treatment. Part of this simulation involves the creation of an immobilization device that will be used for the duration of your treatments to keep you in the same position each and every time you are treated. A mask may be used for treatments near the head and neck. For other areas of the body, a mold called a vac-lok might be shaped around the area of interest. Marks will be placed on the mask, or on your body to serve as reference points to help our radiation therapists place you in the correct position every day to ensure your treatments are as precise as possible. Your Radiation Oncologist may give you specific instructions on how to prepare for your CT simulation

After your simulation, the images obtained during your CT will be used to plan your treatments. A certified medical dosimetrist, a medical radiation physicist and your radiation oncologist create a specialized plan just for you, taking into account the location and size of the area to be treated as well as the normal structures surrounding the treatment in order to give the correct dose to the affected area and keep all healthy tissue to a minimal dose. Normally you will begin your radiation treatments 3-10 days after simulation. More complex treatments could take longer.

When the planning is complete, you will come in to start your radiation treatments. The first day, plan to spend approximately 30 minutes to an hour (2 hours for stereotactic treatments) in the radiation oncology department. You will be aligned using the marks given on CT simulation, and using measurements from your treatment plan. Our radiation oncologists use advanced imaging before and during radiation treatment so we can closely monitor your treatments. We use highly targeted radiation technologies to deliver maximum radiation doses to tumors, with less impact on healthy tissues and organs. After we ensure that we are targeting the exact treatment area, we will deliver your radiation treatment. You will not experience pain during your radiation treatment. It is of utmost importance that you stay still during your radiation treatment to ensure that the radiation is delivered to the correct area. Your radiation therapists will be monitoring you closely to ensure that you are holding still. Before you leave the treatment room, permanent marks, often called tattoos will be given to help with daily alignment. Your daily treatment time, including the setup and imaging, is usually 10 to 20 minutes, but as long as 2 hours for a stereotactic therapy.

Common types of cancer treated with Radiation at Teton cancer institute include (Not a complete list):

  • Breast
  • Prostate
  • Lung
  • Head and Neck cancers
  • Primary Brain tumors
  • Gynecologic
  • Rectal and Anal
  • Skin Cancer
  • Metastatic cancers to Bone and Brain


Typical radiation therapy can be damaging to the body and cause unpleasant side effects, such as skin changes, fatigue, nausea, and vomiting, or other side effects depending on the part of the body being treated. Side effects are common but go away when treatment is finished. During your radiation treatments, it is crucial to work closely with all of our oncology personnel including medical assistants, oncology nurses, radiation therapists, physicians and dietician in order to reduce side effects. During your radiation it is important to follow good hygiene practices. Using only lotions and soaps recommended by the radiation staff, and do not use deodorant in the treatment area or any lotions or powders that contain sparkle or talc.

Prevention and Risk Factors:

Anything that increases your chances of getting a disease is called a risk factor. Having a risk factor does not mean you will get the disease. Not having a risk factor does not mean you will not get cancer. Cancer is not a single disease, but a group of diseases. Many things in your genes, lifestyle and the environment around us may increase your risk of getting cancer.

Cancer prevention includes avoiding risk factors. Some risk factors for cancer can be avoided, but some cannot. Some people may get cancer even if they do not have a family history of cancer and even if they follow all recommended cancer prevention behaviors. These following suggestions can help lower your chances of developing cancer, and can also help you feel better and improve your quality of life.

  • Avoid eating meats that have been smoked, preserved, salted or cured such as many types of ham, bacon or hot dogs. If you eat red meat, eat only small amounts; eat less than 18 oz. of beef, pork, lamb or other red meats each week.
  • If you drink alcohol, do it in moderation. Only have one or two drinks a day if any.
  • Make time for exercise. Be active for at least 30 minutes each day. Tobacco products, cigarettes, and smokeless tobacco increase your risk of many types of cancer.