What are the benefits of real-time MRI-guided radiation to treat cancer?

Percy Lee, MD
Percy Lee, MD on behalf of UCLA Health
Radiation Oncology
Real-time magnetic resonance imaging (MRI)-guided radiation is especially useful for mobile tumors, which often change position in unpredictable ways. This movement occurs for a number of reasons, including the person’s respiration, heartbeat and muscle contractions. For example, a lung tumor can move an inch or more every few seconds as the person breathes. Tumor movement can also be due to weight changes or the tumor’s response to other treatments. Cancers expected to benefit from non-stop MRI imaging include lung, prostate, bladder and pancreas, along with cancers of the head and neck and central nervous system.

During treatment, MRI-guided radiation captures a steady stream of soft-tissue images in real time and compares them to the planned treatment margins. If the tumor strays outside prescribed margins, the machine can turn the beam off until the tumor returns to its prescribed location.

Current practice allows radiation oncologists to design treatment plans based on images taken days or weeks before the treatment date. If doctors suspect tumor movement from weight loss or other reasons, redesigning a plan can take several days. MRI-guided radiation software allows radiation oncologists to adapt radiation in real time when necessary by creating a customized “plan-of-the-day” for each person. In doing so, radiation that otherwise would have hit healthy tissue is redirected to hone in on malignant tissue, increasing the probability of exact delivery and improving outcomes.

This content originally appeared online at UCLA Health

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