What is Radiation Therapy? 

Radiotherapy (sometimes called radiotherapy, x-ray therapy, or irradiation) uses x-rays to kill cancer cells. These x-rays target cancer sites in the body. Treatment is carefully planned to do as little harm as possible to your healthy body tissues. 

One type of radiation therapy commonly used involves photons, "packets" of energy. Depending on the amount of energy they possess, the rays can be used to destroy cancer cells on the surface or deeper in the body. The higher the energy of the x-ray beam, the deeper the x-rays can go into the body. Linear accelerators are machines that produce x-rays of increasingly greater energy. The use of machines to focus radiation (such as x-rays) on a cancer site is called external beam radiotherapy.

The treatment is usually given over several weeks. The length of treatment will depend on the size and type of cancer and on your general health.

Internal Radiotherapy

Internal radiotherapy is another technique for delivering radiation to cancer cells - radioactive implants are placed directly into a tumor or body cavity. (Brachytherapy, interstitial irradiation, and intracavitary irradiation are types of internal radiotherapy.) In this treatment, the radiation dose is concentrated in a small area, and the patient stays in hospital for a few days.
Radiation therapy may be used alone or in combination with chemotherapy or surgery. Like all forms of cancer treatment, radiation therapy can have side effects. Possible side effects of radiation include temporary or permanent loss of hair in the area being treated, skin irritation, temporary change in skin colour in the treated area, and tiredness. Other side effects are largely dependent on the area of the body that is treated. More information about the side effects associated with radiotherapy can be obtained from your radiation oncologist.

Important information for patients

Simulation
Prior to the start of radiation therapy, you will have to go through a process called simulation (planning). During simulation, you will be asked to lie very still on an examining table while the radiation therapist uses a special x-ray machine to define your treatment field. This is the exact place on your body where the radiation will be aimed.

Simulation may also involve CT scans or other imaging studies to accurately plan how to direct the radiation. Depending on the type of treatment you will be receiving, body moulds or other devices that keep you from moving during treatment (immobilization devices) may be made at this time. They will be used each time you have treatment to ensure you are positioned correctly. The radiation therapist will often mark the treatment port on your skin with tattoos or tiny dots of coloured, permanent ink. It is important that the radiation is targeted at the same area each time. Simulation may take from half an hour to approximately one hour. Once completed, your doctor will meet with the radiation therapist to plan the treatment and this may take 2-3 days.

The total dose of radiation and the number of treatments will depend on the size and location of the tumour, your general health, and other medical treatments you may be receiving. Radiation therapy is usually given five days a week for 4 to 5 weeks. When radiation is used for palliative care, the course of treatment is shorter, usually 1 to 2 weeks.

During treatment: Before each treatment, you may need to change into a hospital gown. It's best to wear clothing that is easy to take off and put on again. In the treatment room, the radiation therapist will use the marks on your skin to locate the treatment area and to position you correctly. For each external radiation therapy session, you will be in the treatment room about 10 to 20 minutes, but you will be getting radiation for only about 2 to 5 minutes of that time.

Receiving external radiation treatments is painless, just like having an x-ray taken. You will not hear, see, or smell the radiation.

The radiation therapist may put special shields (or blocks) between the machine and certain parts of your body to help protect normal tissues and organs. You need to remain very still during the treatment so that the radiation reaches only the area where it is needed and the same area is treated each time. You don't have to hold your breath — just breathe normally.

The radiation therapist will leave the treatment room before your treatment begins, to operate the equipment. Although you may feel alone, keep in mind that the therapist can see and hear you and even talk with you using an intercom in the treatment room (you will be watched on a television screen in the control room). If you feel ill or very uncomfortable during the treatment, tell your therapist at once. The machine can be stopped at any time.

After starting treatment, your doctor and members of your health care team will follow your progress at least once a week, by checking your response to treatment and how you are feeling. When necessary, your doctor may revise the treatment plan by changing the radiation dose or the number and length of your remaining radiation sessions.

Side effects

External radiation therapy does not cause your body to become radioactive. There is no need to avoid being with other people because you are undergoing treatment. Even hugging, kissing, or having sexual relations poses no risk of radiation exposure.

Most side effects of radiation therapy are related to the area that is being treated. Most patients have minimal side effects. Your doctor will tell you about the possible side effects you might expect and how you should deal with them.

Example of Radiotherapy Following Surgery

This patient has a relatively uncommon form of melanoma - Desmoplastic neurotrophic melanoma. There is evidence that radiotherapy after surgery for this type of melanoma can reduce the rate of local recurrence.

	Desmoplastic neurotropic melanoma (photo 1): Histopathology established the tumour to be 1.7 mm thick (Breslow microstaging) and a Rotation flap repair was undertaken.
	Photo 2: shows the result, a few days after surgical removal of the melanoma and reconstruction by rotating skin from the cheek.
	Photo 3: demonstrates Acute radiotherapy skin reaction - redness & crusting.
	Photo 4:  3 months following surgery and radiotherapy