How do radiotherapy machines work

Radiation therapy is also useful in treating some noncancerous benign tumors. Your doctor may suggest radiation therapy as an option at different times during your cancer treatment and for different reasons, including:.

Radiation therapy side effects depend on which part of your body is being exposed to radiation and how much radiation is used. You may experience no side effects, or you may experience several. Most side effects are temporary, can be controlled and generally disappear over time once treatment has ended. Some side effects may develop later. For example, in rare circumstances a new cancer second primary cancer that's different from the first one treated with radiation may develop years later.

Ask your doctor about potential side effects, both short and long term, that may occur after your treatment. Before you undergo external beam radiation therapy, your health care team guides you through a planning process to ensure that radiation reaches the precise spot in your body where it's needed.

Planning typically includes:. After the planning process, your radiation therapy team decides what type of radiation and what dose you'll receive based on your type and stage of cancer, your general health, and the goals for your treatment. The precise dose and focus of radiation beams used in your treatment is carefully planned to maximize the radiation to your cancer cells and minimize the harm to surrounding healthy tissue.

During external beam radiation therapy, you're positioned on a table and a large machine moves around you sending beams of radiation into precise points in your body. External beam radiation therapy is usually conducted using a linear accelerator — a machine that directs high-energy beams of radiation into your body.

As you lie on a table, the linear accelerator moves around you to deliver radiation from several angles. The linear accelerator can be adjusted for your particular situation so that it delivers the precise dose of radiation your doctor has ordered. You typically receive external beam radiation on an outpatient basis five days a week over a certain period of time. There is also a microphone in the treatment room so that the patient can speak to the therapist if needed.

Port films x-rays taken with the treatment beam or other imaging tools such as cone beam CT are checked regularly to make sure that the beam position doesn't vary from the original plan. Safety of the staff operating the linear accelerator is also important.

The linear accelerator sits in a room with lead and concrete walls so that the high-energy x-rays are shielded and no one outside of the room is exposed to the x-rays.

The radiation therapist must turn on the accelerator from outside the treatment room. Because the accelerator only emits radiation when it is actually turned on, the risk of accidental exposure is extremely low. Please type your comment or suggestion into the text box below. Note: we are unable to answer specific questions or offer individual medical advice or opinions.

Please contact your physician with specific medical questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database.

This website does not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. Web page review process: This Web page is reviewed regularly by a physician with expertise in the medical area presented and is further reviewed by committees from the Radiological Society of North America RSNA and the American College of Radiology ACR , comprising physicians with expertise in several radiologic areas.

These sources produce gamma-rays, which have the same effect on cancer cells as X-rays. This treatment reduces damage to surrounding healthy tissue, thereby limiting side effects.

The use of radiotherapy as part of your treatment plan will depend on your diagnosis. For some tumours e. Radiotherapy can increase the effectiveness of other treatments and you can be treated with radiotherapy before surgery to help shrink a tumour and allow less extensive surgery than would otherwise have been needed.

Alternatively you may be treated with radiation after surgery to destroy small amounts of cancer cells that may have been left behind. For example, if you have breast cancer, you may have surgery to remove the tumour first, chemotherapy to destroy cancer cells that may have travelled to other parts of the body and then radiotherapy to destroy any remaining cancer cells.

The best outcomes for patients occur when treatment plans are determined through discussions between multi-disciplinary cancer medical specialists. These specialists will review your case and use their expertise to determine the best combination of treatment and in which order you should receive it.

The actual treatment may last only several minutes. The duration of a patient's treatment depends on the method of treatment delivery, such as IMRT, and the dose given. The length of each treatment will usually be the same from day to day.

Patients usually receive radiation treatments once a day, five days a week for a total of two to nine weeks. The patient's diagnosis determines the total duration of treatment. Occasionally, treatments are given twice a day. External beam therapy is painless but patients will hear buzzing or clicking noises during treatment. The linear accelerator may rotate or move during treatment. Patients feel nothing out of the ordinary, but may sometimes smell an odd smell during treatment that is caused by the ozone produced by the linear accelerator.

Some patients may also see a colored light when they receive their treatment; this event is especially true for patients having their brain or eye treated.

Your doctor may recommend a series of follow-up exams after treatment. These may include a physical check-up, imaging exam s , and blood or other lab tests. These visits help your doctor see if your condition is stable or has changed.

They also allow you to discuss any treatment side effects with your doctor. Once treatment is complete, patients are asked to return for follow-up visits. During these appointments, patients will undergo evaluation, including imaging exams or blood tests, to determine if their cancer has been eliminated or if additional treatment is required.

Even if the cancer has been cured, patients can expect to continue periodic visits to follow-up with their doctor. Please type your comment or suggestion into the text box below. Note: we are unable to answer specific questions or offer individual medical advice or opinions.

Please contact your physician with specific medical questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database.

This website does not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region.