BACKGROUND AND PURPOSE: In carbon ion radiotherapy (CIRT), the use of different relative biological effectiveness (RBE) models in the RBE-weighted dose (DRBE) calculation can lead to deviations in the physical dose (Dphy) delivered to the patient. Our aim is to reduce target Dphy deviations by converting prescription dose values. MATERIAL AND METHODS: Planning data of patients treated at the National Institute of Radiological Sciences (NIRS) were collected, with prescribed doses per fraction ranging from 3.6Gy (RBE) to 4.6Gy (RBE), according to the Japanese semi-empirical model. The Dphy was Monte Carlo (MC) re-calculated simulating the NIRS beamline. The local effect model (LEM)_I was then applied to estimate DRBE. Target median DRBE ratios between MC+LEM_I and NIRS plans determined correction factors for the conversion of prescription doses. Plans were re-optimized in a LEM_I-based commercial system, prescribing the NIRS uncorrected and corrected DRBE. RESULTS: The MC+LEM_I target median DRBE was respectively 15% and 5% higher than the NIRS reference, for the lowest and highest dose levels. Uncorrected DRBE prescription resulted in significantly lower target Dphy in re-optimized plans, with respect to NIRS plans. CONCLUSIONS: Prescription dose conversion factors could minimize target physical dose variations due to the use of different radiobiological models in the calculation of CIRT RBE-weighted dose.
BACKGROUND AND PURPOSE: In carbon ion radiotherapy (CIRT), the use of different relative biological effectiveness (RBE) models in the RBE-weighted dose (DRBE) calculation can lead to deviations in the physical dose (Dphy) delivered to the patient. Our aim is to reduce target Dphy deviations by converting prescription dose values. MATERIAL AND METHODS: Planning data of patients treated at the National Institute of Radiological Sciences (NIRS) were collected, with prescribed doses per fraction ranging from 3.6Gy (RBE) to 4.6Gy (RBE), according to the Japanese semi-empirical model. The Dphy was Monte Carlo (MC) re-calculated simulating the NIRS beamline. The local effect model (LEM)_I was then applied to estimate DRBE. Target median DRBE ratios between MC+LEM_I and NIRS plans determined correction factors for the conversion of prescription doses. Plans were re-optimized in a LEM_I-based commercial system, prescribing the NIRS uncorrected and corrected DRBE. RESULTS: The MC+LEM_I target median DRBE was respectively 15% and 5% higher than the NIRS reference, for the lowest and highest dose levels. Uncorrected DRBE prescription resulted in significantly lower target Dphy in re-optimized plans, with respect to NIRS plans. CONCLUSIONS: Prescription dose conversion factors could minimize target physical dose variations due to the use of different radiobiological models in the calculation of CIRT RBE-weighted dose.
Authors: Amelia Barcellini; Viviana Vitolo; Lorenzo Cobianchi; Andrea Peloso; Alessandro Vanoli; Alfredo Mirandola; Angelica Facoetti; Maria Rosaria Fiore; Alberto Iannalfi; Barbara Vischioni; Francesco Cuccia; Sara Ronchi; Maria Bonora; Giulia Riva; Rachele Petrucci; Emma D'Ippolito; Francesca Dal Mas; Lorenzo Preda; Francesca Valvo Journal: In Vivo Date: 2020 May-Jun Impact factor: 2.155
Authors: KyungDon Choi; Stewart B Mein; Benedikt Kopp; Giuseppe Magro; Silvia Molinelli; Mario Ciocca; Andrea Mairani Journal: Cancers (Basel) Date: 2018-10-23 Impact factor: 6.639
Authors: Piero Fossati; Ana Perpar; Markus Stock; Petra Georg; Antonio Carlino; Joanna Gora; Giovanna Martino; Eugen B Hug Journal: Int J Part Ther Date: 2021-06-25