At Siteman Cancer Center, radiation therapy is not simply a treatment modality, it is a highly sophisticated discipline that combines advanced imaging, treatment planning, and precision delivery to target cancer with remarkable accuracy. As part of an NCI-designated Comprehensive Cancer Center, WashU Medicine radiation oncologists are advancing the field through research, clinical innovation, and the translation of new discoveries into patient care.
Radiation therapy uses precisely targeted beams of energy, or particles (photons, protons, or electrons) to treat cancer while minimizing exposure to nearby healthy tissues and critical organs. Modern radiation techniques allow physicians to customize treatment based on the location of a tumor, its relationship to surrounding anatomy, and the goals of care, creating highly individualized treatment plans for each patient.
Because cancer treatment often requires multiple therapeutic approaches, radiation therapy is integrated into multidisciplinary care planning alongside surgery, medical oncology treatments, immunotherapy, and clinical trials. This collaborative approach helps ensure that every patient receives a treatment strategy informed by the expertise of specialists across cancer disciplines.
More than half of all cancer patients will receive some form of radiation, whether by itself or in combination with other treatment options such as surgery, chemotherapy, hormone therapy, or immunotherapy. Benign, non-cancerous tumors also might be treated with radiation.
Our Siteman care coordinators – oncology-trained nurses who help with scheduling, finding the right specialist, and guidance – can help you through the process.
Call us directly or submit a form, and we will call you back.
Radiation Therapy for Adults and Children
The radiation therapy you receive at Siteman gives you a distinct advantage in your care because we bring together cutting-edge technology and the expertise of WashU Medicine radiation oncologists. Our specialists don’t just administer treatment, they helped develop it.
Radiation therapy is not one treatment. It is a family of highly specialized therapies, each designed for a specific kind of cancer, location, and patient. At Siteman, your care team selects the exact right approach for your specific tumor — its size, location, biology, and what matters most to you. The goal is always the same: to achieve the best possible outcome by delivering the highest effective dose to the cancer while protecting the healthy tissue around it.
This precision matters. It means fewer side effects, faster recovery, and treatments designed around your body.
Siteman Kids at St. Louis Children’s Hospital
When cancer affects a child, they need specialized pediatric oncology care. The WashU Medicine experts at Siteman Kids at St. Louis Children’s Hospital carefully consider a child’s developing brain, bones, organs, and developing reproductive system. The pediatric radiation oncologists at Siteman Kids are skilled at using advanced technologies like pencil beam proton therapy to target tumors with precision while protecting the surrounding tissue that is still growing.
Types of Radiation Therapies
External Beam Radiation Therapy is delivered from outside of the body and targeted precisely at your cancer cells.
Intensity Modulated Radiation Therapy (IMRT) uses advanced computer software to break radiation into thousands of tiny, thin beams that are shaped or sculpted to match the unique 3D shape of your tumor.
Image-Guided Radiation Therapy (IGRT) uses frequent imaging (CT, MRI, or X-rays) to precisely locate and track tumors before and during each radiation session.
MRI-Guided Linear Accelerator (MR-LINAC) incorporates live, real-time MRI scanning to monitor moving tumors in the lungs or pancreas while the patient breathes, immediately pausing the beam if the tumor moves outside of the radiation beam boundaries. We were the first in the world to use this technology in patients.
Proton Beam Therapy uses proton particles instead of standard X-ray photons to treat cancer. The advantage is that protons deposit radiation directly inside of a tumor and stop, without harming healthy tissue behind the tumor. We were the first in the region to offer proton beam therapy, in the S. Lee Kling Proton Therapy Center at Siteman
Pencil-Beam Proton Therapy (PBPT) is a highly precise type of proton radiation therapy used in both adults and children. Siteman Cancer Center was the first in the region to offer this advanced therapy. Instead of using one large beam of radiation, this 3D technology enables radiation oncologists to direct a single, pencil-thin beam of radiation and deliver doses layer-by-layer deep into a tumor while following a 3D map that identifies the exact location and edges of the tumor. This precision allows proton therapy to be used safely for brain and spinal cord tumors, pediatric cancers, sarcomas, lymphomas, and cancers in the head, neck, skull, lung, breast, and prostate.
High Intensity, Short Course Radiation Therapies
Advanced technologies that deliver highly concentrated doses in a fraction of the time allow you to get back to your life faster. That can mean just a handful of treatment days instead of six to eight weeks of daily radiation appointments.
Stereotactic Body Radiation Therapy (SBRT): SBRT delivers an ultra-high dose of radiation to tumors in the body (such as the lungs, liver, or spine) in just one to five total sessions. The number of sessions depends on the location of the tumor and its size. It is highly effective for both localized adult cancers and specific pediatric solid tumors.
Gamma Knife Radiosurgery: Despite the name, this involves no surgery or incisions. It is a highly specialized robotic system designed to treat brain tumors, and vascular malformations, and some neurological conditions. It aims hundreds of precise beams at a single point to treat brain tumors or neurological conditions. It is completed in one visit, without a hospital stay.
CyberKnife: This non-invasive radiosurgery involves the use of a robotic arm that moves and rotates around you while delivering radiation beams from multiple angles. It is often used for the treatment of brain and spinal tumors as well as prostate cancer, lung, liver, pancreas. and kidney tumors. Treatment is usually completed in five or fewer outpatient visits.
Hypofractionated Radiation Therapy: We are leaders in hypofractionated radiation therapy, which delivers highly concentrated radiation doses in fewer treatment sessions. This can shorten the treatment plan from weeks to days for many breast, prostate, and pediatric bone cancers. Our physicians currently are offering clinical trials testing hypofractionated therapies on various cancers, including melanoma.
Hyperthermia Therapy: Uses gentle microwave energy to warm the tumor area to a precise temperature. This temporary warming safely relaxes the tumor’s defenses, making the cancer cells significantly more vulnerable while undergoing radiation treatments. It can be used for breast cancer and solid tumors.
Internal Radiation Therapies
Sometimes the best way to destroy cancer is from the inside out. At Siteman Cancer Center, radiation oncologists can place radiation directly into a tumor or use smart molecules to track down and kill cancer cells wherever they hide in the body.
Brachytherapy: This technique involves placing temporary or permanent radioactive sources (seeds or ribbons) directly inside or right next to the tumor. We have one of the largest brachytherapy programs in the country, with more than 1,000 treatments provided each year. Siteman Cancer Center also is a leader in using high-dose-rate (HDR) brachytherapy, providing highly successful, localized treatment for adult gynecological and breast cancers, as well as specific childhood cancers.
Intraoperative Radiation Therapy (IORT): This is a radiation treatment done while you are undergoing surgery. Your surgeon first removes a cancerous tumor and then your radiation oncologist will treat the surrounding tissue with radiation while you are still in the operating room. It is commonly used for the treatment of some breast and gynecologic tumors, as well as some colon and skin cancers.
Theranostics: We are a global leader in theranostics, an advanced form of cancer treatment, which combines specially engineered radioactive tracers (called radiopharmaceuticals) combined with advanced imaging to find and map cancer cells throughout the body and then deliver targeted cancer-destroying drugs. We use these pioneered therapies for advanced prostate cancer, neuroendocrine tumors, and thyroid cancers in both adults and pediatric patients.
Theranostics at Siteman
“Theranostics operates the way a key and lock do. We design a radiopharmaceutical that looks for a certain biomarker on the surface of cancer cells and, once found, the radiopharmaceutical then inserts itself into that biomarker. We then use scans to visualize the cancer cells detected by the tracer. When we can see what we need to treat, we can then treat what we see.”
Vikas Prasad, MD, Director, WashU Medicine Clinical Theranostics Program
Why Choose Siteman
What distinguishes radiation therapy at Siteman Cancer Center is not simply access to advanced technology, but the expertise used to apply it. WashU Medicine radiation oncologists help advance the field through research, clinical innovation, and disease-specific expertise across a wide range of cancers. This combination of scientific leadership, collaborative care, and precision treatment planning allows patients to receive care informed by the latest advances in radiation oncology.
When you choose radiation therapy at Siteman Cancer Center, your care is guided by the same physicians who built the technologies, wrote the protocols, and trained the specialists who now lead programs across the country. That depth of expertise translates directly into better outcomes for you.
WashU Medicine radiation oncologists at Siteman Cancer Center treat 3,500 patients annually — nearly half of all radiation oncology patients in the region—and provide 76,000 treatments each year.
National leaders in Radiation Oncology
WashU Medicine physicians and scientists helped to develop the world’s first full-body computed tomography (CT) scanner and invented the first positron emission tomography (PET) scanner. Later advancements included a larger, more open “Big Bore” CT scanner and the world’s first live, MRI-guided adaptive radiation system (MR-LINAC), which integrates real-time magnetic resonance images with radiation beams and allows for continuous tracking of moving tumors while treatment is under way. WashU Medicine radiation oncologists at Siteman were also the first in the St. Louis region to offer advanced proton beam therapy for the treatment of cancers, and the first to offer ultrasound-guided permanent seed prostate implants, high dose brachytherapy, stereotactic radiosurgery, intensity modulated radiotherapy (IMRT) and 3D treatment planning technology.
With all these groundbreaking achievements and a track record for excellence in patient care, the WashU Radiation Oncology program and all seven Siteman Cancer Center locations have earned multi-year accreditation by the American Society of Radiation Oncology (ASTRO) Accreditation Program for Excellence (APEx). Additionally, Siteman’s radiation therapy teams at Barnes- Jewish Hospital and Memorial Hospital Shiloh have earned APEx accreditation for excellence in Radiopharmaceutical Therapy.
Safer, shorter, more precise radiation therapies
With one of the largest radiation oncology departments in the United States, our expertise at Siteman Cancer Center enables us to design and offer safer, shorter, and more effective radiation treatments. Your cancer is specific to you, and so is your treatment plan. At Siteman, WashU Medicine radiation oncologists offer the full range of personalized radiation options so they can:
- Sculpt high-dose, ultra-precise treatments specifically around your body, your organs, and your personal cancer type.
- Adjust and track radiation beams to account for your breathing and movement so that your radiation therapy kills cancer cells while not harming healthy surrounding tissue.
- Target tumors with maximum force and pinpoint precision, which can shorten the number of treatments you need.
Radiation oncologists aren’t just experts in oncology; they specialize in your specific cancer, ensuring your physician is fully focused on your disease and the latest treatments for it.
Further, Siteman Cancer Center is recognized with the highest rating of “Exceptional” by the National Cancer Institute (NCI) and is the only NCI-designated Comprehensive Cancer Center in Missouri and southern Illinois. Because of this credential, our patients receive healthcare here that they can’t receive anywhere else in the region.
Experts Lead Every Kind of Radiation Therapy
Your cancer is specific to you. So is your treatment at Siteman. WashU Medicine radiation oncologists offer every advanced radiation option available — and the expertise to know exactly which one is right for your specific diagnosis.
Radiation therapy might be your only prescribed treatment, or it might be used in combination with other therapies such as surgery, hormone therapy, chemotherapy, or immunotherapies. Your doctor might prescribe radiation that is:
- Primary Treatment: As your only recommended treatment for your specific cancer
- Before Surgery (Neoadjuvant): To shrink tumors so they are easier to remove surgically
- After Surgery (Adjuvant): To destroy any remaining microscopic cancer cells to help prevent recurrence
- Alongside Chemotherapy (Chemoradiation): To sensitize cancer cells and increase overall treatment effectiveness
- For Advanced-Stage Cancers: For palliative care, to shrink tumors and ease complications such as nerve compression, pain, or bleeding
Radiation Safety at Siteman
Precision medicine designed to protect healthy tissue
At Siteman Cancer Center, protecting healthy tissue is a fundamental part of radiation treatment planning. WashU Medicine radiation oncologists use advanced imaging, sophisticated treatment planning, and highly precise delivery techniques to target cancer while minimizing exposure to nearby organs and critical structures.
This focus on precision is especially important when treatment involves areas such as the heart, lungs, brain, reproductive organs, or other sensitive tissues. Specialists carefully consider both immediate treatment goals and long-term health outcomes when developing individualized treatment plans. For patients concerned about fertility, radiation oncologists work closely with specialists at WashU Medicine’s Fertility and Reproductive Medicine Center. For children, treatment planning takes into account growth, development, and the potential long-term effects of therapy, helping to preserve health and quality of life both during and after treatment.
Advanced heart-sparing expertise
For patients receiving radiation near the chest — for breast or lung cancer, for example — preventing cardiotoxicity (heart-related side effects) is a top priority. Our cancer specialists work side-by-side with heart specialists in the WashU Medicine Cardio-Oncology Center of Excellence to design the best treatment plan that not only targets your cancer but also protects your heart. The specialists in the center helped to establish global standards for patient heart safety during cancer treatments.
WashU Medicine radiation therapists teach a specialized breathing technique called Deep Inspiration Breath Hold (DIBH) to naturally expand your lungs and lower your diaphragm during treatment. The process physically moves your heart safely away from the chest wall and out of the path of radiation beams.
Cardio-Oncology Center of Expertise
The WashU Medicine Cardio-Oncology Center of Excellence is designated as a Gold Center of Excellence by the International Cardio-Oncology Society.
Fertility preservation
Radiation near the reproductive organs can affect your ability to start or grow your family. Siteman addresses this from the very beginning of your treatment plan. Undergoing treatment with radiation can impact the ability to conceive. For patients who want to pursue parenthood, Siteman has treatment and services that support family planning.
Siteman partners with WashU Medicine’s Fertility and Reproductive Medicine Center to help patients preserve their fertility while undergoing treatment. They have extensive expertise in egg and sperm cryopreservation before or after cancer treatment.
Children and radiation therapy at Siteman Kids
There are many considerations for pediatric patients that differ from adult treatment. Siteman Kids at St. Louis Children’s Hospital is ranked #1 in the region for pediatric cancer care. With advanced, highly precise radiation technologies, such as pencil beam radiation therapy, we can protect your child’s developing brain, heart, bones, and reproductive organs from unnecessary radiation exposure. Child Life specialists at Siteman Kids also offer mock scanner practices and child-friendly conversations to help kids better understand and feel safe during actual treatment sessions. If needed, we have a specialized pediatric anesthesia team onsite to offer gentle sedation during radiation sessions.
Your Second Opinion at Siteman
Siteman wants to be your first choice for cancer care, but that might not always be possible. If you have received a cancer diagnosis, started care somewhere else, or are a physician seeking specialized care for your patient, ask us about a second opinion. You can start the process. To make it easy, our care coordinators guide scheduling for yourself or your patient.
What to Expect During Radiation Treatments
At Siteman Cancer Center, our team will guide you every step of the way, from your initial consultation with us through long-term follow-up care after your cancer treatment — so you know what to expect, you have a plan, and you have peace of mind.
The first step
During your first visit, you or your child will meet with a dedicated clinical nurse coordinator and a radiation oncologist. We will review your medical records with you to get to know you, your history, and your goals. We then will review any existing imaging and lab tests and schedule more, if needed.
Once our team identifies or confirms the exact type and location of your cancer, we will discuss radiation therapy options. You can ask questions at any time and determine how you want to proceed.
Your “mapping” session
Because radiation is never a “one-size-fits-all” approach, we will create a personalized treatment plan designed for your specific type of cancer and location. We have advanced 3D mapping technology to precisely map where the cancer cells are located. Child Life specialists at Siteman Kids will guide your child through mock scanner practices during therapeutic play time. If your child needs gentle sedation to stay perfectly still during scanning sessions, our pediatric anesthesia team will work closely with us to obtain the needed scans.
Once you are done, your radiation oncologist will work with a team of specialists (dosimetrists and medical physicists) to map out how, where, and when the radiation beams will be targeted at your cancer.
Treatment days
Depending on the type of radiation therapy, you will undergo specific radiation treatments over a period of time. You usually follow the same process from one treatment day to the next and are under the expert care of your radiation therapist. They are at your side and working behind the scenes with the latest software and robotics to constantly refine, direct, and re-focus radiation beams on your cancer, even as your body moves or you breathe, and as your tumors shrink over time.
Long-term follow-up
Once you complete your radiation treatments, your doctor will schedule follow-up visits to monitor your health. Between visits your care team is available to answer questions or address any concerns you may have.
Multidisciplinary treatment team
At Siteman Cancer Center, your radiation treatment is planned by a multidisciplinary team of WashU Medicine specialists working closely, not one doctor working alone. Your team will include radiation oncologists, surgical oncologists, medical oncologists, radiologists, pathologists, and others. Together they review your case as an integrated care team. They examine your medical records, imaging studies, biopsies, and genetic tests to ensure you receive an accurate diagnosis and staging before making any recommendations about treatment.
While you may just undergo radiation therapy to treat your cancer, radiation is also commonly used before or after surgery or in combination with other therapies.
Clinical trials are research studies that help us find new ways to prevent, diagnose, and treat cancer. If you have a rare or complex diagnosis or your treatment path seems uncertain, you might qualify for a clinical trial.
Our team will help you find a study that is right for you. Call us to speak with a Siteman care coordinator.
Why Choose Our Experts
WashU Medicine radiation oncologists at Siteman Cancer Center are leaders in some of the most advanced areas of cancer treatment, including proton therapy, stereotactic body radiation therapy (SBRT), theranostics, breast cancer radiation oncology, pediatric oncology, head and neck cancer treatment, and translational cancer research. Their work helps shape national standards of care while bringing the latest innovations directly to patients throughout the region.
Clifford G. Robinson, MD
National leader in lung cancer radiation therapy and stereotactic body radiation therapy (SBRT)
Dr. Clifford Robinson is internationally recognized for advancing the use of stereotactic body radiation therapy (SBRT) and other highly precise radiation treatments for lung cancer and cancers of the chest. A leader in national clinical trials, he has helped shape modern approaches to treating complex thoracic cancers and is at the forefront of developing novel applications of radiation therapy, including cardiac radioablation for heart rhythm disorders.
Stephanie M. Perkins, MD
National expert in proton therapy and pediatric radiation oncology
Dr. Stephanie Perkins is one of the country’s leading specialists in proton therapy and pediatric radiation oncology. As director of the S. Lee Kling Proton Therapy Center, she focuses on delivering highly targeted treatments that help reduce long-term side effects for children, adolescents, and young adults with cancer. Her expertise has helped expand access to advanced proton therapy across the region and beyond.
Carmen R. Bergom, MD, PhD
Nationally recognized breast cancer radiation oncologist and physician-scientist
Dr. Carmen Bergom is a nationally recognized expert in breast cancer radiation therapy whose research has helped advance understanding of how radiation affects the heart and surrounding healthy tissues. Her work focuses on developing safer, more personalized treatment approaches that maximize cancer control while minimizing long-term side effects for breast cancer patients.
Julie K. Schwarz, MD, PhD
Leader in translational radiation oncology research and precision cancer therapy
Dr. Julie Schwarz is a nationally recognized physician-scientist whose work bridges cancer biology and radiation oncology. Her research focuses on understanding why tumors respond differently to treatment and how radiation can be tailored to individual patients. Through leadership of major research initiatives, she is helping drive the next generation of precision radiation therapy.
Jeff Michalski, MD, MBA
National authority in prostate cancer, theranostics, and personalized cancer treatment
Dr. Jeff Michalski is a nationally respected leader in prostate cancer care and one of the pioneers advancing theranostics in oncology. His expertise combines molecular imaging, targeted radiopharmaceutical therapies, and precision radiation treatment to help personalize care for patients with prostate and other genitourinary cancers. He has played a leading role in national clinical trials that have helped define standards of care for prostate cancer treatment.
Wade L. Thorstad, MD
National expert in head and neck cancer radiation therapy
Dr. Wade Thorstad is recognized for his expertise in treating complex head and neck cancers using advanced radiation techniques. Working within a multidisciplinary team, he helps develop personalized treatment plans that balance cancer control with preservation of critical functions such as speech, swallowing, and quality of life. His clinical leadership has helped establish comprehensive approaches to care for patients with some of the most challenging cancer diagnoses.
Frequently Asked Questions About Radiation Therapy
Most appointments last about an hour. That includes time for precise positioning and real-time imaging. This is work that happens in the background before the beam is ever turned on. With our expertise in shortened, high- dose radiation plans, you may be able to complete your radiation sessions in as little as one to five days or just two to three weeks, versus other options that may take six to eight weeks. Your oncologist will let you know how long each procedure will take and how many sessions you need.
No. Radiation treatment feels similar to a standard X-ray: You don’t feel the beam. You may feel some discomfort from needing to lie still or if you need a custom immobilization device to keep you perfectly positioned.
Clinical trials at Siteman open up new and unique treatment options for our patients. We give patients a level of access and options they can’t find everywhere. That means patients at Siteman have a distinct advantage over their disease.
Siteman leads one of the largest clinical trial programs in the country, with over 600 active trials across all cancer types. As the only NCI-designated Comprehensive Cancer Center in the region, Siteman offers access to groundbreaking clinical trials not generally available elsewhere. Some clinical trials even are initiated by our specialists first before moving on to multi-center, national or global clinical trials.
Siteman has a dedicated Radiation Oncology Clinical Trials Group that includes renowned WashU radiation oncologists. We are actively evaluating new, more effective radiation therapies in clinicala trials including:
- Hypofractionated Radiation Therapy Combined with Immunotherapy: We are testing shorter, higher-dose radiation schedules paired with immunotherapies for melanomas.
- Advanced Proton Therapy Protocols: We are investigating the use of proton craniospinal irradiation versus traditional radiotherapy for certain metastatic cancers.
- Novel Delivery Methods: We are a leading center evaluating the use of tile-based brachytherapy (GammaTile) for the treatment of brain tumors (Radiation One and Done Study, ROADS), which are radiation seeds embedded in foam tiles and inserted into the brain during surgery. The use of the tiles speeds up the timing for radiation treatment and already has been shown to improve metastatic brain tumor outcomes.
