Related Experiment Video
Updated: Aug 12, 2025
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Initial clinical experience with magnetic resonance-guided radiotherapy in pediatric patients: Lessons learned from a
Matthew D Hall1,2, Kathryn E Mittauer1,2, Roberto Herrera1
1Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, United States.
Insights
Magnetic resonance-guided radiotherapy (MRgRT) shows promise in pediatric cancer care, offering well-tolerated treatments with significant organ at risk sparing. This advanced radiotherapy technique may benefit selected pediatric patients, particularly for thoracic and abdominal tumors.
Area of Science:
- Oncology
- Radiation Oncology
- Pediatric Oncology
Background:
- Magnetic resonance-guided radiotherapy (MRgRT) is gaining traction in adult cancer treatment.
- Published data on MRgRT for pediatric patients is scarce, limited to a few case reports.
- This study addresses the limited experience with MRgRT in children.
Purpose of the Study:
- To report on the institutional experience with MRgRT in pediatric patients over a four-year period.
- To describe key considerations for selecting and applying MRgRT in children.
- To evaluate treatment outcomes and toxicities in pediatric patients receiving MRgRT.
Main Methods:
- Retrospective review of all patients treated with MRgRT from April 2018 to April 2022.
- Evaluation of pediatric patients receiving imaging or treatment with a magnetic resonance-guided linear accelerator (MR Linac).
- Summary of four pediatric cases treated with MRgRT, including outcomes and toxicities.
Main Results:
- Four pediatric patients received MRgRT during the study period.
- Treatments included stereotactic ablative radiotherapy (SABR) and fractionated radiotherapy.
- No Grade 2 or higher toxicities were observed; MRgRT demonstrated significant organ at risk sparing compared to other modalities.
Conclusions:
- MRgRT was well-tolerated in four pediatric patients, with no severe acute effects.
- MRgRT offers potential advantages for specific pediatric tumor sites, including thoracic/abdominal/pelvic targets.
- Selected pediatric patients may benefit from MRgRT due to superior organ at risk sparing and adaptive replanning capabilities.
Purpose/Objectives:
Magnetic resonance-guided radiotherapy (MRgRT) is increasingly used in a variety of adult cancers. To date, published experience regarding the use of MRgRT in pediatric patients is limited to two case reports. We report on the use of MRgRT for pediatric patients at our institution during a four-year period and describe important considerations in the selection and application of this technology in children.
Materials/Methods:
All patients treated with MRgRT since inception at our institution between 4/2018 and 4/2022 were retrospectively reviewed. We also evaluated all pediatric patients treated at our institution during the same period who received either imaging or treatment using our magnetic resonance-guided linear accelerator (MR Linac). We summarize four clinical cases where MRgRT was selected for treatment in our clinic, including disease outcomes and toxicities and describe our experience using the MR Linac for imaging before and during treatment for image fusion and tumor assessments.
Results:
Between 4/2018 and 4/2022, 535 patients received MRgRT at our center, including 405 (75.7%) with stereotactic ablative radiotherapy (SABR). During this period, 347 distinct radiotherapy courses were delivered to pediatric patients, including 217 (62.5%) with proton therapy. Four pediatric patients received MRgRT. One received SABR for lung metastasis with daily adaptive replanning and a second was treated for liver metastasis using a non-adaptive workflow. Two patients received fractionated MRgRT for an ALK-rearranged non-small cell lung cancer and neuroblastoma. No Grade 2 or higher toxicities were observed or reported during MRgRT or subsequent follow-up. Twelve patients underwent MR imaging without contrast during treatment for brain tumors to assess for tumor/cystic changes. Two patients treated with other modalities underwent MR simulation for target volume delineation and organ at risk sparing due to anatomic changes during treatment or unexpected delays in obtaining diagnostic MR appointments.
Conclusions:
In four pediatric patients treated with MRgRT, treatment was well tolerated with no severe acute effects. At our center, most pediatric patients are treated with proton therapy, but the cases selected for MRgRT demonstrated significant organ at risk sparing compared to alternative modalities. In particular, MRgRT may provide advantages for thoracic/abdominal/pelvic targets using gated delivery and adaptive replanning, but selected patients treated with fractionated radiotherapy may also benefit MRgRT through superior organ at risk sparing.
