Comparative Study Evaluating a New Dose Optimization Software for Gamma Knife Treatment Planning: Comparison of 80 Challenging Treatment Plans.

Abstract

Introduction: In 2020, Elekta Instrument AB, Stockholm, released a new dose optimizer for Leksell GammaPlan, which includes the possibility of inverse planning. This study aimed to compare the new software with the previous manual version of treatment planning for stereotactic radiosurgery and evaluate its performance.

Materials and methods: Four types of diagnoses - vestibular schwannomas, pituitary adenomas, meningiomas, and single brain metastasis - along with 80 clinically approved challenging cases, were selected for testing the new software. Key parameters, including coverage, selectivity, target volume, and doses to critical structures, were collected and statistically analysed using a t test. These parameters were compared based on the Leksell Gamma Knife (LGK) Society standardization document for stereotactic radiosurgery, both for each diagnosis and for the entire dataset.

Results: The new software showed a clear advantage, particularly in sparing critical structures while maintaining or improving treatment plan conformity. Doses to critical structures such as the optic nerve, brainstem, cochlea, and pituitary gland decreased by an average of 13% (0.76 Gy), 7% (0.52 Gy), 7% (0.2 Gy), and 14% (1.04 Gy), respectively, reducing toxicity. Other plan parameters also showed significant improvements, except for the gradient index. Selectivity improved by 11% (0.03), the Shaw Conformity Index improved by 10% (0.1), and coverage improved by 0.01. Additionally, treatment time was reduced by 10% enhancing patient comfort.

Conclusion: Overall, LGK Lightning is faster and produces treatment plans with superior parameters compared to manual planning.