A simple technique for cranio-spinal irradiation in pediatric patients

Purpose: Field matching poses challenges in craniospinal irradiation (CSI) as it leads either to underdosage or overdosage in the junctional area. A simple technique for CSI in pediatric patients is proposed.
Materials and Methods: Computed tomography scans were performed in the prone position. Two lateral cranial fields and a direct posterior spinal field were planned with a common central axis. Half-beam-blocked cranial fields with zero collimator rotation were used for treating the cranium. A half-beam-blocked field defined with jaws was used to treat the spinal column at an extended source-to-surface distance. Before treating the patient, matching of the cranial and spinal field junction along the central axis was verified with an extended dose range film.
Results and Conclusion: The technique described is simple and easy to implement and can be applied to pediatric patients undergoing CSI. This method has the potential to reduce daily setup time and setup errors. This technique is ideally suitable for patients with spinal fields less than 30 cm.

Keywords
Craniospinal irradiation, field-junction, medulloblastoma, radiotherapy