Radiation therapy is a common type of cancer treatment that uses high-energy particles, such as x-rays, gamma rays, electron beams or protons, to shrink tumors and kill cancer cells by damaging their DNA. As the DNA is damaged, the cancer cells stop dividing, slowing the growth of tumors. When the cancer cells eventually die, the body breaks them down and eliminates them.
Radiation therapy may be used alone or with other types of cancer treatment, including surgery, chemotherapy or both. Depending on many factors, including the type, size and location of the cancer, there are three types of radiation therapy patients may receive: external beam radiation therapy, internal radiation therapy or systemic radiation therapy.
Types of Radiation Therapy
External beam radiation therapy comes from a machine outside of the body that uses electricity to create high-energy subatomic particles. Most commonly, external beam radiation therapy is received daily for several weeks. Internal radiation therapy, or brachytherapy, is delivered by placing sealed radioactive isotopes inside of the body using needles or catheters.
Internal radiation therapy may be given in high or low dosage rates and may be temporary or permanent. Internal radiation therapy is commonly used to treat prostate cancer, and may be used alone or in combination with external beam radiation therapy.
Systemic radiation therapy is given to patients orally or intravenously in combination with a monoclonal antibody to target the radioactive substance to the right location in the body. Systemic radiation therapy is commonly used in thyroid cancer, or as a method of pain relief for cancers that have spread to the bones.
The Treatment Process
Treatment options will depend on a number of factors, including the type of tumor, the extent of the disease at the time of diagnosis and the patient's medical history. Personal feelings about the treatment, quality of life and lifestyle will also be important considerations in your physician's assessment and recommendations. A radiation oncologist—a doctor with special training in using radiation to treat diseases—will prescribe the type and amount of treatment that best suits the patient's needs.
After a physical exam and review of the patient's medical history, the radiation oncologist will do some special planning to pinpoint the treatment area.
In a process called simulation, the patient will be asked to lie very still on a table while the radiation therapist uses a special x-ray machine or CT unit to define the fields to be treated. This process may take 30 minutes to an hour, and devices may be constructed to hold you in one position. This will help ensure that the patient lies in the same position for each radiation treatment. Marks will be placed on the skin that will be used to position the patient for treatment. A return appointment will be scheduled to verify and begin treatments.
After simulation, the physician will decide how much radiation is needed, how it will be delivered and how many treatments are needed. Treatment planning computer software is then used to examine the most effective techniques for treatment.
Each patient has a special treatment, so the area to be treated and the length of treatment are different for each person. Much of the time in the treatment room is spent setting up the area to be treated. The actual treatment takes just a few minutes each day.
Side Effects of Radiation Therapy
As radiation therapy kills cancer cells, healthy cells may also become damaged, leading to acute and chronic side effects. Side effects depend on the type of radiation therapy, the part of the body treated, the dose received and other treatments received. Acute side effects occur during treatment and typically disappear after radiation therapy is complete. Acute side effects can include skin irritation, hair loss, fatigue, nausea and vomiting. Chronic side effects can occur up to years after radiation therapy ends and can include fibrosis, memory loss, infertility and rarely, a second form of cancer.
Things to Remember
- All side-effects that occur during radiation therapy are manageable.
- The radiation passes through the body and does not remain in you. You are not radioactive.
- Only the body part in the field of radiation is affected.
- Normal cells exposed to radiation begin to repair themselves soon after exposure.
- Make sure to get plenty of rest. Get more sleep at night, take naps during the day and let family members help when they can.
- Side-effects usually improve within a few weeks.
Radiation Therapy at Baptist Cancer Center
Baptist Radiation Oncology Centers offer a full range of high-tech radiation equipment, including:
- Simulators with CT and 4D (motion management) capability
- Linear accelerators
- CyberKnife accelerator
- Two, three, and four-dimensional treatment planning computer systems
- High dose rate brachytherapy unit
- Prostate brachytherapy programs