Radiation Therapy | What is it? | MedStar Health
A team of radiation oncologists from MedStar Health pose for a photo in a treatment room.

What is radiation therapy?

Radiation therapy, also called radiation oncology, is one of the primary treatments for many cancers and is prescribed for more than one-half of cancer patients. It uses high-energy radiation beams (including X-rays, gamma rays, electrons, and protons) to destroy cancer cells. This treatment can be delivered by a machine outside the body using external-beam radiation therapy. It can also come from radioactive material placed in the body near cancer cells using internal radiation therapy, called brachytherapy.

Your therapy will be managed by a radiation oncologist, a doctor who specializes in the use of radiation to treat cancer. The type of radiation therapy you receive depends on your individual cancer treatment plan developed by your radiation oncology team. Following your treatment, you will have periodic scans to determine how your cancer responded to the radiation therapy. Sometimes, the results from the therapy are immediate. Other times, it takes weeks or months for cancer to respond.

Our approach

The most advanced, targeted, and personalized radiation oncology therapies

Our team of highly experienced, specialized physicians is dedicated to providing personalized, high-quality radiation therapies for a wide range of conditions. We combine our medical expertise with state-of-the-art technology and access to the latest clinical research to deliver treatment options that improve outcomes and your quality of life.

Our expert radiation oncologists can develop treatment plans with pinpoint accuracy by using the latest treatment planning technology to map precise tumor locations. This ensures that tumors get the most effective dose while sparing healthy tissues and organs.

Our goal is to help you heal by providing a full suite of radiation oncology treatments at our physician offices and hospital-based centers close to where you live and work in Washington, D.C., and Maryland.

A team approach with decades of combined experience

We have a team approach to cancer, with board-certified specialists in numerous disciplines. Our specialists use the most advanced therapies available, tailored to your needs. Our team includes:

  • Radiation oncology specialists
  • Medical oncology
  • Surgeons
  • Pathologists
  • Physicists
  • Radiologists
  • Radiation therapists
  • Dosimetrists
  • Nurses
  • Nurse navigators
  • Social workers
  • Administrative support staff

How it is used

MedStar Health cancer specialists use this type of therapy in the following ways:

  • Primary treatment: The only treatment needed to destroy the cancer cells (Certain cancers do not respond to or need surgery, so radiation is an option)
  • In conjunction with chemotherapy: When radiation and chemotherapy are given together, it’s called chemoradiation or chemoradiotherapy
  • Neoadjuvant radiation: To shrink a tumor as much as possible before surgery, often in conjunction with chemotherapy
  • Adjuvant radiation therapy: Radiation after surgery to keep cancer from returning
  • Intraoperative radiation therapy: Radiation during surgery
  • Symptom relief: To relieve certain symptoms of the cancer

The type of therapy prescribed depends on many factors, including:

  • The type and size of cancer
  • Where the tumor is located in your body
  • How close it is to other organs
  • What other kinds of cancer treatment you will need or have received
  • Your general health and medical history

Side effects of radiation therapy

High doses of radiation attack and destroy cancer cells but may also affect some healthy cells in the process. This may cause side effects. Radiation side effects vary for different people and depend on the kind of cancer you have and the part of your body the radiation is targeting.

The two most common side effects of this type of therapy are fatigue and changes in the color of the skin in the radiated area. Your skin may become dry, pink, or itchy. Other possible side effects include:

  • Hair loss
  • Mouth discomfort, when treating the area around the mouth
  • Throat discomfort, when treating the head and neck area
  • Nausea and vomiting, when treating around the stomach
  • Diarrhea, when treating around the abdomen and pelvis
  • Sexual changes and fertility problems, when treating around the pelvis

At MedStar Health, your team of cancer experts will help you manage the possible side effects of radiation treatment.

Types of radiation therapy

Our wide range of sophisticated medical equipment allows us to treat tumors aggressively and reduce some of the side effects of radiation treatment. Here, you'll find several types of radiation techniques and technologies, including:

Brachytherapy (internal radiation therapy)

Brachytherapy involves placing radioactive "seeds" inside the body near a tumor. The pellets, or seeds, release targeted doses of radiation at precise locations while limiting the radiation exposure to healthy tissue. We offer low-dose rates (LDR) and high-dose rates (HDR), guided robotically.

External beam radiation therapy

This type of radiation treatment uses a linear accelerator to aim high-energy radiation beams at your cancer from outside your body. Our specialists focus these beams directly on your cancer, avoiding unnecessary damage to your healthy tissue. External beam radiation therapy is the most frequently used treatment for breast cancers.

  • 3D conformal radiotherapy sculpts radiation beams to the shape of a tumor, making it ideal for tumors with irregular shapes or for those close to healthy tissues and organs. We view a tumor in three dimensions with the help of advanced imaging. Based on the dosimetry or treatment plan, we then deliver radiation beams from several directions to the cancer cells.

    • Image-Guided Radiation Therapy (IGRT) uses high-quality imaging technology to create pictures of a tumor during the radiation procedure. Using these images, your radiation team carefully adjusts radiation beams and doses during the procedure to best fit the tumor's size, shape, and location while sparing normal tissues. IGRT can integrate respiratory motion technology to track the exact position of a tumor while a patient is breathing. It's primarily used for patients

      • Whose tumors are near critical structures

      • When an immediately adjacent area has been previously irradiated

      • When dose escalation is planned and conventional means of targeting are inadequate

    • Intensity-modulated radiation therapy (IMRT) uses devices that allow the radiation beamlets to move and change intensity depending on what kind of tissue they are targeting. This flexibility allows different areas of a tumor to receive different amounts of radiation and helps protect surrounding healthy tissue from unnecessary radiation exposure.

Intraoperative radiation therapy (IORT)

IORT is a single-dose radiation alternative applied directly to the targeted area or tumor at the time of surgery. This precision ensures that normal surrounding tissue is spared. IORT is typically used to treat early-stage breast cancer, as well as pancreatic cancer and related tumors. It offers a multitude of benefits, including:

  • Lower recurrence rates

  • Safe treatment with fewer side effects

  • Shorter treatment duration (One dose vs. six weeks of traditional radiation therapy)


Intraoperative Radiation Therapy (IORT): IntraOp® Mobetron®

For people who have been diagnosed with pancreatic cancer, liver cancer, or sarcomas, MedStar Georgetown University Hospital is the region’s only hospital that offers a powerful treatment that studies have shown reduces disease recurrence and improves outcomes--IntraOp® Mobetron®. This leading-edge radiation therapy is applied directly to the tumor or tumor bed and margins for a single treatment during surgery.

Benefits of IntraOp Mobetron

  • Treatment only takes a few minutes during surgery, so additional visits for radiation are not needed.
  • Treatment with IntraOp Mobetron decreases the risk of the cancer returning and improves outcomes.
  • Radiation is precisely targeted, so it spares surrounding healthy tissue.
  • Intraoperative radiation is safe, painless, and effective.
  • This treatment may be an option for people who would previously may not have been considered for surgery.

Who is a good candidate for IntraOp Mobetron?

The treatment is used for people who have locally advanced liver or pancreatic cancer or sarcoma. That means that the cancer has spread to nearby tissue or lymph nodes. MedStar Georgetown’s multidisciplinary team of pancreatic and liver cancer specialists carefully review each case to determine if intraoperative radiation therapy is appropriate for each patient.

Proton therapy with HYPERSCAN technology

This highly advanced radiation treatment destroys cancer cells with protons, or positively charged particles. More precise than traditional radiation, proton therapy targets tumors by matching their exact shape and size, sparing surrounding healthy tissue and resulting in fewer side effects. Proton therapy also reduces the potential for secondary cancers.

  • We are the first and most experienced facility to offer proton therapy in the Washington, D.C., region.

  • We are the first in the world to offer the most advanced proton therapy with HYPERSCAN technology (intensity-modulated proton therapy-IMPT)

Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT)

This novel technology delivers large doses of highly focused radiation to the tumor site, sparing as much surrounding healthy tissue as possible. It's non-invasive, requiring no surgical incision. The procedure can be performed outpatient, often with little to no patient recovery time. We use three different technology systems to deliver this type of radiation: 

  • CyberKnife® is an advanced technology that uses robotic technology to administer this radiation therapy anywhere in the body, even in places previously considered unreachable.

  • The Edge radiosurgery system offers a new line of defense in the fight against cancer. It delivers radiation to each part of the tumor from many different angles, minimizing the radiation dose to adjacent healthy tissue.

  • ZAP-X® is modern radiosurgery designed to treat brain tumors. MedStar Health was the first healthcare organization on the East Coast and the third in the world to offer ZAP-X gyroscopic stereotactic radiosurgery (SRS) for brain tumors.

Additional treatment options

We also offer patients the variety of other treatment options listed below, each with its unique benefits:

  • Advanced computerized treatment planning, image fusion, and verification systems

  • Conventional radiation therapy

  • Electron beam therapy 

  • Image-guided radiation therapy (IGRT)

  • Intensity-modulated radiation therapy (IMRT)

  • Partial breast irradiation with both external beam therapy and brachytherapy

  • Positron emission tomography (PET) and computed tomography (CT) simulation

  • RapidArc volumetric arc therapy (VMAT)

  • Respiratory gating

  • State-of-the-art 4-D large-bore computerized tomography (CT) simulator

  • Systemic radiation therapy

The specific type of treatment you need often depends on where the cancer is located. Your radiation therapy team will evaluate your case and develop a treatment plan that is most effective for you.


What to expect

During your initial visit to the radiation oncology department, your radiation oncologist will review your pathology, diagnostic images, medical history, and pertinent laboratory data and will also examine you. Based on this information, the radiation oncologist works together with your other oncology specialists and doctors and with you to develop your treatment plan.

We'll schedule a special planning session with you if radiation therapy is recommended. A radiation oncology nurse will provide you with general information about radiation therapy, as well as disease-specific information. Before starting treatments, the nurse will discuss and provide information in writing about site-specific side effects and recommendations for managing those side effects.

During your treatments, you will meet with the nurse and doctor weekly to review your response to treatment and assess any side effects that you may have developed. During these weekly visits, you will have an opportunity to ask the nurse and doctor questions.

We understand that patients who are managing cancer need support beyond the clinic. Therefore, we have a variety of patient and family support services, including nutritionists, social service counselors, financial counselors, psychosocial counselors, support groups, and more.

Frequently asked questions

  • What types of cancers can radiation treat?

    We are experts in helping patients with their treatment for the following cancers:

  • Will I be able to work during radiation treatments?

    Your ability to work while receiving therapy will depend on the area being treated. Your doctor can explain any restrictions you will have during treatment.

  • Will I be able to drive, or should someone come with me to my treatments?

    In most cases, you'll be able to drive yourself to and from treatment, but you'll want to discuss this with your doctor first to be sure.

  • Will I be able to choose my treatment time?

    We will make every effort to offer you a time slot that fits your schedule.

  • Can I drink alcoholic beverages while under treatment?

    Social drinking (one to two drinks) may be allowed for some patients, but you should discuss this with your doctor.

Looking for expert cancer care?

With multiple locations throughout the region, patients have access to many of the nation’s renowned cancer specialists offering high quality care, second opinions and a chance for better outcomes close to where they live and work. Georgetown Lombardi Comprehensive Cancer, one of the nation’s comprehensive cancer centers designated by the National Cancer Institute (NCI), serves as the research engine allowing patients access to clinical trials that often lead to breakthroughs in cancer care.

Our locations

Distance from Change locationEnter your location

MedStar Health: Radiation Oncology at MedStar Franklin Square Medical Center

White Square Professional Building
9105 Franklin Square Dr.
Ste. 100
Baltimore, MD 21237

MedStar Health: Radiation Oncology at MedStar Good Samaritan Hospital

Russell Morgan Building
5601 Loch Raven Blvd.
Ste. G4
Baltimore, MD 21239

MedStar Health: Radiation Oncology at MedStar Georgetown University Hospital

3800 Reservoir Rd., NW
Lower Level (LL)
Bles Building
Washington, DC 20007

MedStar Health: CyberKnife at MedStar Georgetown University Hospital

3800 Reservoir Rd., NW
CB-18 Lower Level (LL) Bles Bldg.
Washington, DC 20007

MedStar Health: Radiation Oncology at MedStar Washington Hospital Center

110 Irving Street, NW
Room CG118
Washington, DC 20010


Research and clinical trials


MedStar Health is the clinical partner of Georgetown Lombardi Comprehensive Cancer Center, the only National Cancer Institute (NCI)-designated comprehensive cancer center in the Washington, D.C., region. This partnership allows patients to access the latest breakthroughs in cancer care. Of the 1,500+ cancer programs across the country, only 51 (or 3%) of those centers are awarded this prestigious designation.

Learn how our collaborative research accelerates treatment innovations and enhances patient outcomes.

Clinical trials

By developing and testing new ways to combat cancer through cutting-edge clinical trials, we can discover breakthrough advancements designed to help our current and future patients.

Educational opportunities

The Radiation Research Division is at the forefront of academic molecular investigations into radiation-resistant cancer cells.