Laura Masi1, Margherita Zani2, Raffaela Doro2, Silvia Calusi3, Vanessa Di Cataldo2, Ivano Bonucci2, Samantha Cipressi2, Giulio Francolini4, Pierluigi Bonomo5, Lorenzo Livi6. 1. Department of Medical Physics and Radiation Oncology, IFCA, I-50139 Firenze, Italy. Electronic address: l.masi@giomi.com. 2. Department of Medical Physics and Radiation Oncology, IFCA, I-50139 Firenze, Italy. 3. Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, I-50139 Firenze, Italy. 4. Department of Medical Physics and Radiation Oncology, IFCA, I-50139 Firenze, Italy; Department of Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, I-50139 Firenze, Italy. 5. Department of Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, I-50139 Firenze, Italy. 6. Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, I-50139 Firenze, Italy; Department of Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, I-50139 Firenze, Italy.
Abstract
PURPOSE: This study evaluated the plan quality of CyberKnife MLC-based treatment planning in comparison to the Iris collimator for abdominal and pelvic SBRT. Multiple dosimetric parameters were considered together with a global scoring index validated by clinical scoring. METHODS AND MATERIALS: Iris and MLC plans were created for 28 liver, 15 pancreas and 13 prostate cases including a wide range of PTV sizes (24-643 cm3). Plans were compared in terms of coverage, conformity (nCI), dose gradient (R50%), homogeneity (HI), OAR doses, PTV gEUD, MU, treatment time both estimated by TPS (tTPS) and measured. A global plan quality score index was calculated for IRIS and MLC solutions and validated by a clinical score given independently by two observers. RESULTS: Compared to Iris, MLC achieved equivalent coverage and conformity without compromising OAR sparing and improving R50% (p < 0.001). MLC gEUD was slightly lower than Iris (p < 0.05) for abdominal cases. MLC reduced significantly MU (-15%) and tTPS (-22%). Time reduction was partially lost when measured. The global score index was significantly higher for MLC solutions which were selected in 73% and 64% of cases respectively by the first and second observer. CONCLUSION: Iris and MLC comparison was not straightforward when based on multiple dosimetric parameters. The use of a mathematical overall score index integrated with a clinical scoring was essential to confirm MLC plans advantages over Iris solutions.
PURPOSE: This study evaluated the plan quality of CyberKnife MLC-based treatment planning in comparison to the Iris collimator for abdominal and pelvic SBRT. Multiple dosimetric parameters were considered together with a global scoring index validated by clinical scoring. METHODS AND MATERIALS: Iris and MLC plans were created for 28 liver, 15 pancreas and 13 prostate cases including a wide range of PTV sizes (24-643 cm3). Plans were compared in terms of coverage, conformity (nCI), dose gradient (R50%), homogeneity (HI), OAR doses, PTV gEUD, MU, treatment time both estimated by TPS (tTPS) and measured. A global plan quality score index was calculated for IRIS and MLC solutions and validated by a clinical score given independently by two observers. RESULTS: Compared to Iris, MLC achieved equivalent coverage and conformity without compromising OAR sparing and improving R50% (p < 0.001). MLC gEUD was slightly lower than Iris (p < 0.05) for abdominal cases. MLC reduced significantly MU (-15%) and tTPS (-22%). Time reduction was partially lost when measured. The global score index was significantly higher for MLC solutions which were selected in 73% and 64% of cases respectively by the first and second observer. CONCLUSION: Iris and MLC comparison was not straightforward when based on multiple dosimetric parameters. The use of a mathematical overall score index integrated with a clinical scoring was essential to confirm MLC plans advantages over Iris solutions.
Authors: Denis Panizza; Valeria Faccenda; Raffaella Lucchini; Martina Camilla Daniotti; Sara Trivellato; Paolo Caricato; Valerio Pisoni; Elena De Ponti; Stefano Arcangeli Journal: Front Oncol Date: 2022-04-07 Impact factor: 5.738