Kadir Yaray1, Edrine Damulira1. 1. Department of Radiation Oncology, M.K. Dedeman Oncology Hospital, School of Medicine, Erciyes University, Kayseri, Turkey.
Abstract
BACKGROUND: The dosimetric characterization of volumetric modulated arc therapy (VMAT)-based total-body irradiation (TBI) in pediatric patients is evaluated. MATERIALS AND METHODS: Twenty-two patients between the ages of 2 and 12 years were enrolled for VMAT-based TBI from 2018 to 2020. Three isocenters were irradiated over three overlapping arcs. While prescribing 90% of the TBI dose to the planning treatment volume (PTV), two fractions (2 Gy each) were delivered each day; hence 12 Gy was delivered in six fractions. During treatment optimization, the mean lung and kidney doses were set not to exceed 7 Gy and 7.5 Gy, respectively. The maximum lens dose was also set to less than 4 Gy. Patient quality assurance was carried out by comparing treatment planning system doses to the 3-dimensional measured doses by the ArcCHECK® detector. The electronic portal imaging device (EPID) gamma indices were also obtained. RESULTS: The average mean lung dose was 7.75 ± 0.18 Gy, mean kidney dose 7.63 ± 0.26 Gy, maximum lens dose 4.41 ± 0.39 Gy, and the mean PTV dose 12.69 ± 0.16 Gy. The average PTV heterogeneity index was 1.15 ± 0.03. Average differences in mean kidney dose, mean lung dose, and mean target dose were 2.79% ± 0.88, 0.84% ± 0.45 and 0.93% ± 0.47, respectively; when comparing planned and ArcCHECK® measured doses. Only grade 1-2 radiation toxicities were recorded, based on CTCAE v5.0 scoring criteria. CONCLUSIONS: VMAT-TBI was characterized with good PTV coverage, homogeneous dose distribution, planned and measured dose agreement, and low toxicity.
BACKGROUND: The dosimetric characterization of volumetric modulated arc therapy (VMAT)-based total-body irradiation (TBI) in pediatric patients is evaluated. MATERIALS AND METHODS: Twenty-two patients between the ages of 2 and 12 years were enrolled for VMAT-based TBI from 2018 to 2020. Three isocenters were irradiated over three overlapping arcs. While prescribing 90% of the TBI dose to the planning treatment volume (PTV), two fractions (2 Gy each) were delivered each day; hence 12 Gy was delivered in six fractions. During treatment optimization, the mean lung and kidney doses were set not to exceed 7 Gy and 7.5 Gy, respectively. The maximum lens dose was also set to less than 4 Gy. Patient quality assurance was carried out by comparing treatment planning system doses to the 3-dimensional measured doses by the ArcCHECK® detector. The electronic portal imaging device (EPID) gamma indices were also obtained. RESULTS: The average mean lung dose was 7.75 ± 0.18 Gy, mean kidney dose 7.63 ± 0.26 Gy, maximum lens dose 4.41 ± 0.39 Gy, and the mean PTV dose 12.69 ± 0.16 Gy. The average PTV heterogeneity index was 1.15 ± 0.03. Average differences in mean kidney dose, mean lung dose, and mean target dose were 2.79% ± 0.88, 0.84% ± 0.45 and 0.93% ± 0.47, respectively; when comparing planned and ArcCHECK® measured doses. Only grade 1-2 radiation toxicities were recorded, based on CTCAE v5.0 scoring criteria. CONCLUSIONS: VMAT-TBI was characterized with good PTV coverage, homogeneous dose distribution, planned and measured dose agreement, and low toxicity.
Authors: Jeffrey Y C Wong; Andrea Riccardo Filippi; Bouthaina Shbib Dabaja; Joachim Yahalom; Lena Specht Journal: Int J Radiat Oncol Biol Phys Date: 2018-05-02 Impact factor: 7.038
Authors: Andreas Springer; Josef Hammer; Erwin Winkler; Christine Track; Roswitha Huppert; Alexandra Böhm; Hedwig Kasparu; Ansgar Weltermann; Gregor Aschauer; Andreas L Petzer; Ernst Putz; Alexander Altenburger; Rainer Gruber; Karin Moser; Karin Wiesauer; Hans Geinitz Journal: Radiat Oncol Date: 2016-03-22 Impact factor: 3.481