Skip to Main Content

Radiation Therapy

  • A cancer treatment that uses high-energy rays or particles to kill cancer cells
  • For the treatment of different kinds of cancer
  • A dosimetrist helps determine the treatment plan by calculating total number of sessions needed
  • Involves Therapeutic Radiology, Pediatric Radiotherapy, and Yale cancer center

Radiation Therapy


If you or a loved one is diagnosed with cancer, you may find it helpful to learn about radiation therapy, a commonly used cancer treatment. It is effective for treating almost all types of cancer in almost any part of the body. Half of all people with cancer are treated with radiation therapy, and it is a key reason why the number of people whose cancer is cured is rising every day.

When you are unfamiliar with radiation therapy, you may wonder how something that we are generally supposed to be avoiding in our day-to-day lives—radiation from the sun, microwaves or from dental X-rays—could be helpful in treating diseases. This type of treatment (of which there are many forms) harnesses the destructive power of high-energy rays or particles (radiation) to kill cancer cells, while taking great care to minimize harm to nearby healthy tissue.

“When radiation is used at high doses, it can be used to treat many cancers throughout the body,” explains Lynn Wilson, MD, a Yale Medicine radiation oncologist and vice chair of the Department of Therapeutic Radiology. Other terms used to describe radiation therapy include radiotherapy, X-ray therapy, cobalt therapy, electron beam therapy or irradiation.

Specialized equipment helps doctors to aim high doses of radiation at tumors or areas of the body where there is disease, explains Dr. Wilson. The goal is to target cancerous cells while preserving as many healthy cells that surround tumors as possible.

How does radiation therapy work?

Radiation is a special kind of energy carried by waves or a stream of particles. It can come from special machines or from radioactive substances.

High doses of radiation can kill cells or keep them from growing and dividing. “Radiation therapy is a useful tool for treating cancer because cancer cells grow and divide more rapidly than many of the normal cells around them,” says Dr. Wilson.

Although some normal cells are affected by radiation, in general it appears that normal cells are better able to fully recover from the effects of radiation than cancer cells. Doctors take special care to carefully limit the intensity of treatments and the area being treated, so that the cancer will be affected more than normal tissue.

What are the benefits and goals of radiation therapy?

For many patients, radiation therapy is the only kind of treatment needed for their cancer. Many others have in combination with other cancer treatments, which include surgery, chemotherapy and biological therapy.

Radiation therapy can be used before surgery to shrink a tumor. After surgery, radiation therapy may be used to stop the growth of any cancer cells that remain. Your doctor may choose to use radiation therapy and surgery at the same time, delivering both in one session in a procedure known as intraoperative radiation. In some cases, doctors use radiation along with anticancer drugs to destroy the cancer, instead of surgery.

Even when curing a particular patient’s cancer is not possible, radiation therapy still can bring relief. Many people find the quality of their lives improved when radiation therapy is used to shrink tumors, which can reduce pressure, bleeding, pain, or other symptoms of cancer. This is called palliative care.

Are there risks involved?

Radiation therapy does pose some risks to patients, as is also true with many other treatments for disease. The brief, high doses of radiation that damage or destroy cancer cells also can hurt normal cells, which is what causes many of the well-known side effects of cancer treatment. These may include hair loss, skin problems and fatigue, among other things.

However, for many patients, the benefit to be gained by killing the cancer cells exceeds the risk and discomfort of the side effects associated with the treatment. 

Doctors consider whether the benefits—including control of disease and relief from symptoms—are greater than the known risks. Although it will be many years before scientists know all of the possible risks of radiation therapy, they now know that it can control cancer.

Who gives radiation treatments?

A doctor who has had special training in using radiation to treat disease is called a radiation oncologist. Your radiation oncologist is the person who prescribes the type and amount of treatment that best suits your needs. He or she works closely with other doctors involved in your care and also heads a highly trained health care team. Your radiation therapy team may also include:

  • A radiation physicist, who makes sure that the equipment is working properly and ensures that the machines deliver the right customized dose of radiation for each patient.
  • A dosimetrist, who helps carry out your treatment plan by calculating the number of treatments you will need and how long each treatment should last.
  • A radiation therapy nurse, who provides nursing care and helps you learn about how your treatment works and how to manage side effects.
  • A radiation therapist, who sets you up for your treatments and runs the equipment that delivers the radiation.

Many patients also benefit from the services of a dietitian, a physical therapist, a social worker and other health care professionals.

Is radiation therapy expensive?

Treatment of cancer with radiation can be costly. It requires very complex equipment and the services of many health care professionals. The exact cost of your radiation therapy will depend on the type and number of treatments you need.

Most health insurance policies, including Part B of Medicare and, in many areas, Medicaid, cover charges for radiation therapy.

Why chose Yale Medicine doctors for radiation therapy?

Yale Medicine’s Department of Therapeutic Radiology is part the Yale Cancer Center at Smilow Cancer Hospital. We offer state-of-the art cancer treatments in other convenient locations throughout Fairfield County and in Derby, Hamden, Guilford and Waterford. Our doctors collaborate with other specialists to deliver personalized care for each of our patients.

Your radiation oncologist develops a treatment design, writes a prescription outlining the treatment course, and consults with the treatment planning team. We consider multiple factors at this point, including the type and size of tumor, pathology, location, nearby anatomical structures, your age, overall health, previous treatment, and the available treatment unit characteristics, among others.

What’s more, Smilow Cancer Hospital is the first in the Northeast to offer a new type of radiation therapy to treat tumors in the lung or bone, whether they are primary tumors or ones that have metastasized, or spread, from original cancer sites.

The RefleXion SCINTIX® BgRT uses positron-emission tomography (PET) imaging technology to guide precision radiation therapy to cancerous tumors, while minimizing the impact to the surrounding area of healthy tissue. The radiation therapy is guided to the tumor by emissions from the patient’s cancer cells during treatment delivery.

For many patients, the best treatment includes a combination of therapies. SCINTIX works alongside chemotherapy, immunotherapy, and targeted drugs.

Smilow offers the most radiation therapy treatment modalities in Connecticut. Its six Radiation Oncology centers (located in New Haven, Greenwich, Guilford, Hamden, Trumbull, and Waterford) are the first and only providers in the state with accreditation by the American Society for Radiation Oncology Accreditation Program for Excellence (APEx).

Patients with cancer in their lungs or bones are welcome, especially with a referral from a physician who can provide a medical history. Each patient must be evaluated to determine if they meet the criteria for potential SCINTIX therapy.

For information or to refer a patient, call 203-200-2000 or submit via Epic or EpicCare Link.