Discussion on the Splitting Treatment Technique in Gamma Knife Treatment Plans

Objective: In clinical Gamma Knife treatment, when patients have multiple or large lesions, a single Gamma Knife plan may require extended treatment time, making it difficult for patients to complete the session. This study explores the proper application of the splitting treatment technique in Gamma Knife treatment plans to create segmented plans for patients. Methods: Utilizing the design and output functions of the radiotherapy planning system, this study examines the typical errors in clinical treatment plans designed for the Moonlight Gamma Knife. Different splitting approaches were analyzed by comparing beam-on time for each target and calculating beam-on time error rates. Based on this, the appropriate splitting treatment technique for Gamma Knife treatment plans was discussed. Results: Scenarios where dose curves of multiple lesions intersect were categorized into three types: complete intersection, partial intersection, and no intersection. Complete intersection cases were further divided into Type I and Type II complete intersections. For cases with completely intersecting dose curves, the Gamma Knife plans should be split using the upper-lower segmentation method. For cases with no intersection, plans can be split based on individual lesions. For partial intersection cases, either the upper-lower segmentation or lesion-based segmentation method may be used. However, careful handling of target weighting at the dose curve intersection is necessary to ensure dose accuracy. For large lesions, the upper-lower segmentation method is recommended. Conclusion: To meet clinical treatment requirements, the proper application of the splitting treatment technique in Gamma Knife treatment plans is essential. This ensures dose accuracy in radiotherapy, thereby guaranteeing treatment efficacy and patient safety.