Fast inverse planning in radiosurgery planning is limited by an excessive number of isocenters, which is clinically hypothesized to be driven by the morphological irregularity of the target volume. This retrospective cross-sectional study aimed to empirically evaluate this hypothesis in vestibular schwannoma cases.
Methods
Consecutive patients diagnosed with vestibular schwannoma and receiving Gamma Knife radiosurgery in 2023 were included, and their treatment plans designed using the GammaPlan planning system were collected. Morphological irregularity–related parameters, including standard sphericity (SS), volume ratio sphericity (VRS), and the coefficient of variance of diameters (DCV), were calculated based on parameters provided by the system. Basic demographic and clinical data were collected to evaluate their impact on sphericity. The effects of different sphericity assessment methods on common treatment plan parameters were analyzed.
Results
Treatment plans of 280 patients with vestibular schwannoma were collected. The SS, VRS, and DCV of the tumors were 0.85 (0.77–0.91), 0.46 ± 0.16, and 0.22 (0.14–0.34), respectively. Multivariate analysis showed that lesion volume, acoustic neuroma consensus on systems for reporting results grade, and age were significant factors influencing sphericity. All other planning parameters, except prescription dose and homogeneity index, were significantly correlated with sphericity. DCV was more closely correlated with SS than with VRS.
Conclusions
DCV may serve as a simple quantitative metric of target morphological irregularity, showing strong consistency with SS. Incorporating morphological irregularity into Gamma Knife treatment plan evaluation may help improve future planning strategies and support optimization of isocenter utilization.
Full text:
https://www.xiahepublishing.com/3067-6150/NSSS-2025-00036
The study was recently published in the Neurosurgical Subspecialties .
Neurosurgical Subspecialties (NSSS) is the official scientific journal of the Department of Neurosurgery at Union Hospital of Tongji Medical College, Huazhong University of Science and Technology. NSSS aims to provide a forum for clinicians and scientists in the field, dedicated to publishing high-quality and peer-reviewed original research, reviews, opinions, commentaries, case reports, and letters across all neurosurgical subspecialties. These include but are not limited to traumatic brain injury, spinal and spinal cord neurosurgery, cerebrovascular disease, stereotactic radiosurgery, neuro-oncology, neurocritical care, neurosurgical nursing, neuroendoscopy, pediatric neurosurgery, peripheral neuropathy, and functional neurosurgery.
