Radiation therapy is the use of high-energy waves (radiation) to treat cancer. The high-energy beams are supplied by special machines or from radioactive substances implanted inside the body. During radiotherapy, specific amounts of radiation are aimed at the tumor or at the part of the body where the cancer exists. The radiation will kill the cancer cells or stop the cancer from spreading.
Types of radiotherapy
There are two major types of radiation therapy, external radiation and internal radiation. External radiotherapy is delivered from a machine called linear accelerator placed outside the body. Internal radiotherapy involves placing a radiation source inside the body at or near the cancer cells. Whenever applied, radiation treats cancer by killing, slowing or stopping the growth of cancer cells. It also can shrink tumors in order to reduce pressure, pain and other side effects when curing the disease is not possible.
Radiation therapy is usually tailored for each patient depending on the location and size of the tumor. To deliver a successful, personalized, safe and effective treatment, a highly skilled medical team works with the patient to create a treatment plan. The team members include a radiation oncologist, radiation oncology nurse, medical radiation physicist, dosimetrist, radiation therapist and other professionals.
- Radiation oncologist: This is a doctor who specializes in treating cancer using radiation. The doctor oversees radiotherapy treatments and works closely with the other team members to create the treatment plan.
- Radiation oncology nurse: This nurse is a specialist in caring for patients receiving radiation treatments. The nurse answers questions about radiotherapy, monitors patient health during treatment, and manages potential side effects.
- Medical radiation physicist: This is a specialist in radiation equipment and works with other team members to design treatment plans
- Dosimetrist: This professional assists with calculating the right radiation dose.
- Radiation therapist: Also called radiation therapy technologist, the therapist operates treatment machines and delivers scheduled treatments.
- Other health care professionals: These are included in the oncology team to provide additional emotional, social and physical support. They include social workers, dentists, physical therapists and nutritionists.
What to expect during your first visit
When radiotherapy may be of help to your condition, your doctor will refer you to a radiation oncologist. At your first visit to the oncologist, the doctor will do a physical exam and review your medical records, X-rays and other diagnostic tests. The oncologist then will discuss the findings with you and decide how to proceed with treatment. A visit to a radiation oncologist is an opportunity to ask questions, clear up concerns and learn about the benefits and potential risks of radiotherapy.
If you choose to undergo radiation therapy, the oncology team will request you to grant permission for the treatment by signing an informed consent form. When you sign the form it means:
- Your oncology team has informed you of all available treatment options.
- You have accepted to undergo radiation therapy.
- You have given caregivers the permission to administer treatment.
- You understand that the treatment does not guarantee the intended results.
What to expect during simulation and planning of treatment
After your first visit to a radiation oncologist and your subsequent decision to undergo radiotherapy, the next visit is typically a planning session and is called a simulation. The simulation session is run without radiation and is used to determine the entire treatment plan, including treatment fields. Of all visits to a radiation oncology facility, it is simulation that often takes the most time.
During a simulation, the oncology team uses imaging scans to identify the location and shape of the tumor. The imaging techniques include computed tomography (CT) scan, magnetic resonance imaging (MRI) and X-ray. Images are generated and transferred to a planning system where virtual 3-dimensional images are obtained and a treatment plan is developed.
For the simulation process, the treatment area is mapped out on the skin using small marks. The marks help the oncology team to aim radiation more precisely at the tumor during subsequent treatments. Alignment is very critical during simulation, so the oncology team will mount lasers on the wall and ceiling to facilitate this. Immobilization devices, such as a tape, foam sponges, molds, plaster casts and headrests, also can be used to keep you in position throughout the session and during each treatment. If the radiation is to be delivered to the neck or head, a thermoplastic mask may be used. It is a mesh mask that has been molded to the face and is secured to the table to gently hold your head in place.
Throughout the simulation session, the room is darkened periodically to allow for setting of treatment fields. Special simulation X-rays of the treatment fields are taken and used to make multiple tattoos on the skin. These tattoos are used during treatment as a guide to the radiation technologist on where to set up treatment fields for daily treatments.
What to expect during treatment planning
After the simulation session, the oncology team will review your information before designing your treatment plan. The plan is usually developed using sophisticated computer software. The software is capable of producing highly complex 3-dimensional representations of the treatment area and the surrounding normal tissues. Likewise, the software is used to calculate the proper radiation dose to be delivered. Apart from computer software, simulation images may be used to create special lead alloy blocks, which are used to block surrounding normal tissues from adverse effects of radiation. It may take many days for treatment planning to be completed, but as soon as it is done then treatment can begin.
What can you expect during treatment?
Radiation is usually delivered in a separate room from that of simulation. The oncology team transfers the treatment fields and treatment plans from the simulation room into the treatment room, which contains a special machine, the linear accelerator, focused on the treatment table. In the treatment room, the radiation oncologist and the technologists verify the treatment plan and recheck the treatment fields and calculations and then begin treatment only when satisfied with the setup.
During treatment, you must lie still on the treatment table to allow the radiation beam to be targeted to the exact area with the tumor. The treatment table and the linear accelerator may be rotated up to 360-degrees if the treatment demands that radiation should hit the tumor from all angles. Once the treatment setup is complete, the technologists will leave the room and monitor the treatment through a video camera and audio link connected to the treatment room. There is no discomfort during treatment and you will not feel the radiation as it is delivered.
Radiotherapy is normally given once a day for 5 days a week, typically at the same time every day. However, there are occasions when
treatment can be given twice a day or less frequently. In fact, the number of treatments depends on a variety of factors and may range from 5-10 to 40 days or more, making the treatment period as long as 1-8 weeks or more. Generally, radiation treatments are given as an outpatient service requiring a relativelyshort time every day.
Although the first few treatments may take an hour or more, a typical daily treatment takes around 15-30 minutes inside the treatment room with the actual treatment lasting only a few minutes. You must never miss a scheduled treatment. Doing so may extend radiotherapy beyond the recommended time, reducing the chance of the tumor being controlled.
After treatment ends, your radiation oncologist will arrange for follow-up appointments for monitoring your recovery and watching for any
radiation side effects. Make sure to work closely with the oncology team to ensure your recovery is as seamless and quick as possible. Remember to request a written record of your radiotherapy from the oncologist as it is useful formanagement of your long-term health care. For more information, visit the “Bay Regional Cancer Center” site.