Silvia Calusi1, Raffaela Doro2, Vanessa Di Cataldo2, Samantha Cipressi2, Giulio Francolini2, Ivano Bonucci2, Lorenzo Livi3, Laura Masi2. 1. IFCA Radiotherapy and Medical Physics Unit, Via del Pergolino, 1, 50139 Florence, Italy; AOU Careggi Medical Physics Unit, Largo Brambilla, 3, 50134 Florence, Italy. Electronic address: silvia.calusi@gmail.com. 2. IFCA Radiotherapy and Medical Physics Unit, Via del Pergolino, 1, 50139 Florence, Italy. 3. AOU Careggi Radiotherapy Unit, Largo Brambilla, 3, 50134 Florence, Italy; University of Florence, Department of Clinical and Experimental Biomedical Sciences "Mario Serio", Viale Morgagni 50, 50134 Florence, Italy.
Abstract
PURPOSE: To assess the performance of a new optimization system, VOLO, for CyberKnife MLC-based SBRT plans in comparison with the existing Sequential optimizer. METHODS: MLC-plans were created for 25 SBRT cases (liver, prostate, pancreas and spine) using both VOLO and Sequential. Monitor units (MU), delivery time (DT), PTV coverage, conformity (nCI), dose gradient (R50%) and OAR doses were used for comparison and combined to obtain a mathematical score (MS) of plan quality for each solution. MS strength was validated by changing parameter weights and by a blinded clinical plan evaluation. The optimization times (OT) and the average segment areas (SA) were also compared. RESULTS: VOLO solutions offered significantly lower mean DT (-19%) and MU (-13%). OT were below 15 min for VOLO, whereas for Sequential, values spanned from 8 to 160 min. SAs were significantly larger for VOLO: on average 10 cm2 versus 7 cm2. VOLO optimized plans achieved a higher MS than Sequential for all tested parameter combinations. PTV coverage and OAR sparing were comparable for both groups of solutions. Although slight differences in R50% and nCI were found, the parameters most affecting MS were MU and DT. VOLO solutions were selected in 80% of cases by both physicians with 88% inter-observer agreement. CONCLUSIONS: The good performance of the VOLO optimization system, together with the large reduction in OT, make it a useful tool to improve the efficiency of CK SBRT planning and delivery. The proposed methodology for comparing different planning solutions can be applied in other contexts.
PURPOSE: To assess the performance of a new optimization system, VOLO, for CyberKnife MLC-based SBRT plans in comparison with the existing Sequential optimizer. METHODS:MLC-plans were created for 25 SBRT cases (liver, prostate, pancreas and spine) using both VOLO and Sequential. Monitor units (MU), delivery time (DT), PTV coverage, conformity (nCI), dose gradient (R50%) and OAR doses were used for comparison and combined to obtain a mathematical score (MS) of plan quality for each solution. MS strength was validated by changing parameter weights and by a blinded clinical plan evaluation. The optimization times (OT) and the average segment areas (SA) were also compared. RESULTS: VOLO solutions offered significantly lower mean DT (-19%) and MU (-13%). OT were below 15 min for VOLO, whereas for Sequential, values spanned from 8 to 160 min. SAs were significantly larger for VOLO: on average 10 cm2 versus 7 cm2. VOLO optimized plans achieved a higher MS than Sequential for all tested parameter combinations. PTV coverage and OAR sparing were comparable for both groups of solutions. Although slight differences in R50% and nCI were found, the parameters most affecting MS were MU and DT. VOLO solutions were selected in 80% of cases by both physicians with 88% inter-observer agreement. CONCLUSIONS: The good performance of the VOLO optimization system, together with the large reduction in OT, make it a useful tool to improve the efficiency of CK SBRT planning and delivery. The proposed methodology for comparing different planning solutions can be applied in other contexts.
Authors: Marta K Giżyńska; Linda Rossi; Wilhelm den Toom; Maaike T W Milder; Kim C de Vries; Joost Nuyttens; Ben J M Heijmen Journal: J Appl Clin Med Phys Date: 2021-01-21 Impact factor: 2.102
Authors: Maaike T W Milder; Alba Magallon-Baro; Wilhelm den Toom; Erik de Klerck; Lorne Luthart; Joost J Nuyttens; Mischa S Hoogeman Journal: Phys Imaging Radiat Oncol Date: 2022-07-28
Authors: Qianyi Xu; Kiet Huynh; Wei Nie; Mark S Rose; Ashish K Chawla; Kevin S Choe; Samir Kanani; Gregory J Kubicek; Jiajin Fan Journal: J Appl Clin Med Phys Date: 2022-03-12 Impact factor: 2.243