Radiation Therapy FAQs

Frequently asked questions about radiation treatment for cancer

A smiling radiation oncologist talks with a cancer patient, representing the support you get from Scripps to answer your questions about radiation therapy.

Dr. Anuradha Koka, Scripps Cancer Center, Scripps Clinic

Frequently asked questions about radiation treatment for cancer

If you’re undergoing radiation therapy for cancer, you may have some questions. We’ve covered the most common questions here, but if you need more information or have specific concerns, always ask your Scripps cancer care team, oncology nurse navigator or radiation oncologist. We want to make sure all of your questions are answered.

What is radiation therapy?

Radiation therapy is a type of medical treatment that uses invisible forms of high energy, such as X-rays and electron beams, to shrink tumors or kill cancer cells.

When is radiation therapy used?

Radiation therapy is most often used to kill cancer cells and ultimately eliminate cancer in the body. In some cases, it may be used for palliative care, which is designed to slow the progress of cancer or treat the symptoms caused by it, such as shrinking a tumor to relieve pain.

How does radiation therapy kill cancer cells?

Radiation beams precisely target tumors to damage the DNA of cancer cells, which prevents them from growing and dividing. Radiation therapy can either damage DNA directly, or create charged particles known as free radicals within the cells that damage the DNA.

Are there different types of radiation therapy?

Yes. Radiation therapy may be delivered by:

  • External-beam radiation therapy, which targets cancer cells from outside of the body
  • Internal radiation therapy, which delivers radiation from radioactive substances placed inside the body near the tumor
  • Systemic radiation therapy, which travels through the whole body in the blood stream to eliminate cancer cells

Find out more about these types of radiation therapy.

How often will I need radiation therapy?

Depending on your individual needs and the type of radiation therapy you’re having, you may have just a few treatments, or you may need multiple treatments over several weeks. Most patients have daily treatments Monday through Friday for five to eight weeks, but your schedule may be different. Your radiation oncologist will discuss your personal treatment plan with you.

Where will I go for radiation therapy treatment?

Scripps provides external-beam radiation treatment at our hospitals and radiation therapy centers. Your treatment location will depend on the type of radiation you have.


Internal radiation treatment and systemic radiation treatment is given in our hospitals.

What can I expect during my radiation therapy session?

It depends on whether you’re having external-beam or internal radiation therapy. Here’s what you can expect before, during and after each type of treatment.

How does my physician decide which type of radiation therapy to use?

Scripps specialists treat many types of cancer using various forms of radiation therapy. The most appropriate type of radiation therapy for each patient depends on several factors.

These include:

  • The type of cancer
  • The size of the tumor
  • Where the cancer is located in the body
  • Whether the cancer has spread
  • Other types of cancer treatment being given
  • How close the tumor is to healthy tissues
  • How far into the body the radiation needs to travel
  • The patient’s overall health and medical history
  • The patient’s preferences and lifestyle

Physicians take these and other factors into consideration when determining the type of radiation therapy that is best for each patient.

Does radiation therapy kill healthy cells?

Radiation therapy may damage healthy cells near the area being treated. This is what causes side effects. Physicians know how much radiation healthy cells can safely receive and still repair themselves, and take this into consideration when planning radiation treatment.

Modern radiation therapy is much more precise than it used to be. Technological advancements, such as 3-D imaging, have created radiation therapy techniques that precisely target cancer cells while minimizing radiation to nearby healthy cells. Advanced imaging also is used to guide radiation oncologists to deliver radiation exactly where it is needed during treatment.

Is radiation used with other treatments?

Radiation therapy is often used in combination with other types of treatments, including surgery and chemotherapy. It may be used before surgery to shrink large tumors and make them easier to remove, or after surgery to kill any cancer cells that were not removed. When radiation therapy is used with chemotherapy, it is known as chemoradiation.


Radiation therapy also may be used alone to treat some cancer types, or to treat cancer in people who cannot have surgery.

Is radiation therapy painful?

Radiation treatment itself is usually painless. Some patients feel warmth in the area where the radiation is being delivered, but there is no sensation of pain. You may have some skin irritation in the treatment area after repeated treatments, as discussed below.

What is a radiation oncologist?

Radiation oncologists are board-certified physicians who prescribe radiation to treat cancers, as well as benign tumors or certain conditions that can benefit from radiation therapy. Scripps radiation oncologists and medical directors of Scripps facilities are among the leaders in their field. Find a Scripps radiation oncologist.

What is a radiation therapist?

Radiation therapists are licensed professionals who administer radiation treatments prescribed by a radiation oncologist. They also handle daily treatment schedules, monitor radiation treatment, maintain patient records and perform regular quality assurance reviews on equipment.

What is a dosimetrist?

Dosimetrists are experts with special training in the design of radiation treatment plans for all types of cancers and benign tumors.

What is a medical physicist?

Medical physicists are experts in the medical application of physics. They have advanced education, training and certification, and they collaborate with radiation oncologists, radiation therapists, dosimetrists and other professionals in radiation treatment strategy and planning.

Is a special diet required during radiation treatment?

Most patients do not need to follow a special diet. But if radiation treatment involves your head, neck, esophagus or digestive organs, you may need to make changes to your eating habits. Your care team will help you make any adjustments.

What are common side effects of radiation?

Some people have side effects from radiation therapy, while others do not. Potential side effects depend on several factors, including the area being treated, the radiation dose, the number of treatments you need and your general health.

Most side effects of radiation therapy happen during or soon after treatment, and generally go away within a few weeks of completing treatment. These include:

Feeling tired

You may feel more tired than usual after your radiation treatments. Get plenty of rest, and allow yourself to nap if you need to.  

Skin irritation

The skin in the area being treated may be irritated, red or look or feel burned. It may become dry, itchy or flaky. Let your care team know about any skin issues. They can tell you the best way to care for your skin. Avoid using any products such as soap, lotions or creams on your skin without first talking to your care team.

Hair loss

You may lose hair in the area being treated. If treatment involves your head, you may lose the hair on your head and face. If this bothers you, your care team can help you find resources for wigs, head wraps and other options while your hair grows back. Some people find that their hair changes texture as it comes back in.

Gastrointestinal problems

Radiation to the pelvis or abdominal area may cause digestive problems, such as nausea or diarrhea. Let your care team know if you experience problems. Medications can help prevent or treat some of these side effects.  

Long-term side effects

Radiation therapy can cause side effects in normal tissue that may not appear for months or years. Talk with your radiation oncologist about the risk of long-term side effects from your treatment.

Let your care team know if you have side effects. We’re here to help you manage them and feel your best during treatment.

Does radiation therapy affect fertility?

Radiation therapy to the pelvic area can affect the reproductive systems of women and men. Your care team will discuss potential side effects for your specific treatment.

Can I have radiation treatments while pregnant?

If you know you are pregnant or there is a possibility of a pregnancy, please tell your radiation oncologist. It is important to avoid radiation therapy during pregnancy.

Will my body be radioactive during or after treatment?

External-beam radiation therapy does not make you radioactive.

During internal therapy (also known as brachytherapy), radioactive material is in your body only while you’re being treated, and will be removed before you leave the treatment center.

Will I be able to continue my usual activities during treatment?

Most patients are able to work, go to school and carry on their usual family and social activities during radiation treatment. You may be more tired than usual, so be sure to take it easy and rest when you need to. If you have any other restrictions, your team will discuss them with you.

Is radiation therapy covered by insurance?

In most cases, Medicare and private medical insurance will cover radiation therapy for cancer. Check with your insurance provider for details.