Doctors use traditional radiation therapy to guide a beam of radiation toward a tumor, making every effort to minimize the effects of that radiation on surrounding healthy tissue. But some tumors are hard to treat this way because the tumors don’t stay put. They move as a patient breathes or even as they digest.
MRI-guided radiation, which Dana-Farber Brigham Cancer Center doctors started using in 2019, uses MRI (Magnetic Resonance Imaging) imaging during the treatment session to account for this motion. This helps direct radiation to the tumor while avoiding healthy tissue in the patient’s body.
“We’re excited to be able to offer this treatment to patients when it’s appropriate,” says Veena Venkatachalam, MD, PhD, a radiation oncologist at Dana-Farber Brigham Cancer Center. “It lets us deliver radiation in a more personalized way.”
When is MRI-guided radiation used?
MRI-guided radiation is most helpful in treating cancers that are in areas of the body that move a lot or are near other vulnerable organs.
For example, some patients with pancreatic cancer might benefit from this approach because pancreatic tumors sit right in the middle of the abdomen and are surrounded by healthy organs. The tumor and surrounding organs move with each breath, so being able to track where the tumor is during treatment is important.
Patients with prostate cancer might also benefit because the prostate can move from one day to the next depending on the fullness of the patient’s rectum. MRI-guided radiation can also be helpful for patients with lung cancer, liver cancer, and metastases from different types of primary tumors. A radiation oncologist will consider each patient’s unique situation when assessing a treatment path.
What are some of the benefits of MRI-guided radiation?
A key benefit of MRI-guided radiation is that doctors can capture movement in real time and use that information to direct radiation to the tumor while avoiding healthy tissue. This can enable doctors to deliver a higher and more effective radiation dose to the tumor while ensuring a lower risk of side effects.
In addition, doctors can adapt the treatment plan from session to session and come up with radiation plans based on the patient’s anatomy at the time of treatment. This can offer advantages over traditional treatment plans, which are generated before treatment starts and then delivered the same way every session. Those plans typically don’t adapt to movement of organs within the body, or changes in the size of the tumor over time.
How does MRI-guided radiation work?
Before treatment, a patient will be guided into the bore of the MRI-guided radiation machine, which looks and acts like an MRI machine but also includes the ability to deliver radiation. The first MRI scan helps doctors plan treatment. Some patients opt to view what the doctors are observing so they can see how their organs are moving with each breath.
During treatment, which typically involves a daily dose for five consecutive days, patients will enter the MRI machine again so that doctors can monitor the tumor location throughout the session. Doctors might ask patients to hold their breath for short periods of time to stabilize the tumor while the machine delivers radiation.
What will I feel during and after MRI-guided radiation?
Patients won’t feel anything during radiation treatment, though they will hear the MRI machine’s clicks. Those who find MRI machines to be uncomfortable might feel anxiety, but doctors can usually help guide patients through the process and make sure they feel comfortable.
After treatment, many patients feel fatigue, though the side effects of radiation vary depending on the part of the body being treated.
How do I know if MRI-guided radiation is an option for me?
MRI-guided radiation isn’t strictly better for all patients. It’s case dependent and something to discuss with your radiation oncologist. Other factors radiation oncologists will consider include the presence of certain types of metal implants, which can preclude the use of MRI scans, and a patient’s comfort with getting an MRI.
About the Medical Reviewer
Dr. Venkatachalam specializes in stereotactic body radiation therapy and MRI-guided radiation treatment for multiple cancer types. In the lab, she studies how the dose and timing of radiation impact the cellular response to radiation treatment, with the focus on p53 signaling. She received her BS in Chemistry and Biology from MIT, her PhD in Biophysics from Harvard University, and her MD from Harvard Medical School. She completed her internship in internal medicine at BWH and residency in radiation oncology in the Harvard Radiation Oncology Program.