Abstract
BACKGROUND: The Lightning(®) software, was added to the Gamma Knife's Leksell GammaPlan(®) as a fully automated inverse planner, differently from the prior software, Wizard(®). In this paper we compare their treatment planning capacity and quality. MATERIALS AND METHODS: Thirty-eight cases were compared under four different planning techniques. First, manual forward planning aided by the Wizard(®) optimization tool. Second, inverse planning with Wizard(®). The third and fourth plans used Lightning(®) with and without consideration for organs at risk (OAR). They were analysed for: planning time, number of shots, coverage, selectivity, gradient index, bean-on time, and OAR dose. Comparison based on pathology was added due to their idiosyncrasies. For quality comparison, dose-volume histograms (DVH) were compared to plans developed under our treatment standards. Tumor's volume and time to plan were correlated with Pearson's coefficient. RESULTS: Lightning(®) had better coverage (8%) and gradient index (15%) but had 12% decrease in selectivity. Planning and delivery times had a reduction of 57% and 5% respectively, despite having three times the number of shots. Only Lightning(®) with protection of OAR met the dose constrains in all plans. DVH showed similar plan qualities. CONCLUSIONS: Lightning(®) allowed the planner to explore different optimization parameters to achieve a plan that suits the clinical problem at hand. It took less time to calculate shots placement, OAR protection and the ideal isodose line than the Wizard(®). This can be useful to plan multiple and complex targets at a faster time, increase the patient's tolerance and, may have a radiobiological advantage by impacting intra-fraction repair.