KEY POINTS
- The guidelines were developed by a task group of four pediatric radiation oncologists and four medical physicists from seven institutions. They were subsequently reviewed and approved by the Children’s Oncology Group Radiation Oncology Discipline, disease committees, Imaging and Radiation Oncology Core, and COG leadership.
- Recommendations cover intracranial treatment, craniospinal irradiation, head and neck, thoracic, abdominal, pelvic, and extremity tumors, as well as SRS, SBRT, brachytherapy, total body irradiation, photon therapy, and proton therapy. They are intended as recommendations rather than mandatory standards.
- Simulation preparation should reflect the child’s age, developmental stage, anxiety, ability to cooperate, and need for anesthesia. Child-life support, parental presence, audiovisual distraction, and other awake techniques should be considered before routine sedation when clinically safe.
- CT slice thickness should generally be 3 mm or less, with 1–1.5 mm slices recommended for cranial tumors and stereotactic treatments. The scan field must include all immobilization equipment, while an additional smaller-field reconstruction may improve target and organ-at-risk delineation.
- Respiratory motion assessment is recommended for thoracic and upper abdominal tumors, but four-dimensional CT should be reserved for situations in which it will meaningfully improve treatment because of its additional imaging dose. Children undergoing breath-hold should ideally reproduce two to three breath holds lasting 20–30 seconds.
- Proton simulation requires consistent placement and full CT inclusion of masks, cushions, range-shifting devices, couch extensions, feeding tubes, and other materials in the beam path. Their stopping powers or densities should be assigned correctly, and anatomical changes during treatment may require repeat imaging and replanning.
- The group recommends child-specific CT protocols and reporting size-specific dose estimates rather than relying only on scanner output metrics. Tube-current modulation may reduce dose while preserving Hounsfield-unit accuracy, whereas changes in tube voltage require caution, particularly for proton stopping-power calculations.
CLINICAL TAKEAWAY
These guidelines provide a practical framework for safer and more reproducible pediatric simulation, including situations involving anesthesia, respiratory motion, stereotactic treatment, and proton therapy. Their central principle is not maximal immobilization or minimal imaging at any cost, but an individualized balance between comfort, reproducibility, image quality, and lifetime radiation exposure.