How Radiation Therapy Works

Stan Benedict, PhD, director of Radiological Physics in the Department of Radiation Oncology, and Paul Read, MD, PhD, vice chair of the Department of Radiation Oncology, contributed this post.

Some cancer patients can be treated with surgery or chemotherapy alone, but about 50 percent will require a form of radiation therapy as part of their cancer treatment. This treatment sends high energy electrons or x-rays at an area of the body to cure the disease or shrink the tumor without damaging surrounding tissue.

Determining whether radiation therapy is needed and the type to use largely depends on the type of cancer as well as the exact location of the cancer inside the body, especially if the cancer is located near sensitive areas, such as the brain.

Which Types Treat Cancer?

The main difference in the three types of radiation therapy is the location of the radiation source used to treat cancers.

• During external beam radiotherapy (teletherapy), the radiation source is located outside a patient’s body. A machine such as a linear accelerator or Gamma Knife directs a focused beam of radiation at the tumor. It’s typically used for:

• Brain, skull and skull base, and spinal tumors
• Breast cancer
• Head and neck cancer
• Lung cancer
• Liver and digestive cancer
• Prostate cancer
• Skin cancer
• Lymphoma and leukemia

• Brachytherapy (sealed source radiotherapy) uses a sealed source of radiation – typically tiny seeds – that are placed inside the patient’s body at or near the site of the cancer. Brachytherapy is used for:
• Prostate cancer
• Head and neck cancer
• Cervical cancer
• Breast cancer
• In systemic radioisotope therapy (unsealed source radiotherapy), the  radiation is taken by pill or liquid medication, or it’s administered through an intravenous (IV) line. It’s most commonly used for:

• Thyroid cancer
• Liver tumors
• Some lymphomas

Radiation Therapy Options at the Emily Couric Clinical Cancer Center

Patients who need radiation therapy have a host of treatment options at the UVA Cancer Center. The new Emily Couric Clinical Cancer Center, which opened in April, offers some of the most advanced external beam radiotherapy and brachytherapy treatment options:

• TomoHD: We’re among the first centers in the world to use TomoHD, an external beam radiotherapy system designed to precisely target radiation treatments to cancerous areas of the body while sparing healthy tissue. A twin machine at Culpeper Regional Hospital syncs with ours, so you can receive the same treatment at both hospitals.
• Varian TrueBeam: We’re also the first center in Virginia to use this linear accelerator. The TrueBeam can more quickly deliver radiation and offers respiratory gating, which provides more accurate treatment for tumors that move as a patient breathes.
• CT on Rails Brachytherapy: Also, we’re among the first centers to use the CT on Rails Brachytherapy suite, which enables patients to receive fast, accurate treatment without being moved to another room for imaging to confirm that the seeds are in the correct location. This is possible because a CT scanner can be moved over a patient to provide imaging, then moved back out of the way once the imaging is complete.

Learn more about the radiation therapy options available at the Couric Center.