Purpose or Case Report: Children with cancer typically require a local MRI scan for primary tumor staging, which is often supplemented by a whole-body PET scan for whole-body staging. Over the past decade, PET-CT was the most widely used modality for whole-body staging across the world. Seven years ago, our team pioneered whole-body 18F-FDG PET-MRI of children with cancer as a "one-stop" alternative with 80% reduced radiation exposure and optimized child-tailored fast and efficient Whole-Body PET/MRI protocols. We then replaced all whole-Body PET/CT studies at our Institution with whole-body PET-MRI as the standard of care for our patients and have performed over 800 Pediatric Whole Body PET MRIs in the last three years.

The purpose of this educational exhibit is to provide a comprehensive review of whole-body PET/MRI technique, imaging patterns in common pediatric malignancies.

The first aim is to briefly explain our Institution's protocol for simultaneous PET/MRI acquisitions. Such simultaneous acquisition results in a convenient, faster, and safer approach for local and whole-body staging in one session. Furthermore, it avoids the need for repetitive anesthesia and imaging and also avoids potential ionizing radiation from PET CTs. The excellent contrast resolution in the MRI provides superior diagnostic detail compared to the CT.

The second aim will present PET/MRI case examples, where either the PET component added value to the MRI or the MRI component added value to the PET, thereby confirming the importance of this integrated hybrid imaging technology. We will present PET/MRI case examples of the following pediatric tumors:
1. Lymphomas:
2. Osseous Sarcomas including Osteosarcoma and Ewing Sarcoma
3. Soft-tissue Sarcomas such as Rhabdomyosarcoma, Desmoplastic small round blue cell tumor. Synovial Sarcoma, Fibrosarcoma, Epithelioid Sarcoma, Alveolar Soft part sarcoma, and Liposarcoma
4. Neuroblastoma
5. Neuroendocrine tumors
6. Malignant Peripheral Nerve Sheath Tumor
7. Germ cell tumors
8. Renal tumors
9. Malignant Liver tumors
10. Langerhan Cell Histiocytosis

As a result of this educational presentation, participants will be able to prescribe a PET/MRI exam for children with cancer, implement tumor-specific protocol modifications, and improve their tumor diagnoses' sensitivity, specificity, and accuracy.
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