Radiation therapy also called radiotherapy, is a form of cancer treatment that makes use of high doses of radiation to kill cancerous cells. High-energy particles or waves, such as x-rays, gamma rays, electron beams, or protons are used in radiation therapy to destroy cancer cells.

The treatment works by damaging cells by destroying the genetic material that controls the growth of cells. Unlike chemotherapy, radiation therapy is a localized treatment. This means that only those areas containing cancerous cells are targetted during the treatment. Healthy cells nearby which may be affected by radiation often repair themselves.

How is radiation therapy used?

Radiation therapy can be used in the treatment of any type of cancer. It may be also useful in treating noncancerous tumors as well. Radiation therapy may be included in your treatment plan in any of the following ways:

• As the primary treatment for cancer
• To shrink a cancerous tumor before undergoing surgery for tumor removal
• To stop the growth of any remaining cancer cells post-surgery
• In combination with chemotherapy
• To relieve the effects of cancer, during the last stages of cancer

How is radiation therapy carried out?

Before undergoing radiation therapy, your medical team will carry out a planning process which includes:

• Radiation simulation- During the simulation process, a comfortable position to receive treatment will be decided upon. After deciding the position, your doctor will mark the areas that will receive the radiation.
• Scans- You will also undergo CT scans to pinpoint the exact location and size of the tumor to be treated.

After the planning process, your specialist will determine the type and dosage of radiation to be administered.

Radiation therapy can be given in one of the following three ways depending on the kind of cancer and where it is. In some cases, more than one type may be used.

• External beam radiation therapy- High-energy rays are directed into the tumor from a machine known as a linear accelerator. It emits X-rays within certain energy limits. Other machines are also available that use energy forms other than X-rays. The treatment will be done over a span of several weeks at radiation therapy hospitals.
• Internal radiation therapy- Also known as brachytherapy, this method involves placing a  radioactive source inside the body, in or near the tumor. The radioactive source will be inside an implant.
• Systemic radiation- System radiation involves the intake of radioactive drug by mouth, through the veins via an IV line or through injections.

What are the risks involved in radiation therapy?

Some people experience few side effects or none at all from radiation therapy. Others may experience more severe side effects. Some of the side effects to be expected include:

• Hair loss and skin irritation
• Fatigue
• Dry mouth and mouth sores with difficulty in swallowing
• Nausea with vomiting
• Bladder irritation with frequent urination
• Diarrhea
• Sexual dysfunction

Most side effects are temporary and subside once the treatment is over.

Results

Periodic scans are necessary after the treatment to see how your body is responding to the treatment. In some cases, the response to treatment is immediate whereas in other cases it may take a longer time to see results.