The influence of basic plan parameters on calculated small field output factors - A multicenter study

Autor: Christian Fiandra, E. Menghi, Marco Esposito, E. Gallio, Cristina Garibaldi, R. Consorti, Stefania Clemente, G. Borzì, Michele Stasi, T. Malatesta, Paolo Bagalà, Serenella Russo, Marco Fusella, Pietro Mancosu, Marta Casati, M. Casale, Anna Delana, Giacomo Reggiori, Maria Daniela Falco
Rok vydání: 2021
Předmět:
Zdroj: Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). 88
ISSN: 1724-191X
Popis: Purpose The influence of basic plan parameters such as slice thickness, grid resolution, algorithm type and field size on calculated small field output factors (OFs) was evaluated in a multicentric study. Methods and materials Three computational homogeneous water phantoms with slice thicknesses (ST) 1, 2 and 3 mm were shared among twenty-one centers to calculate OFs for 1x1, 2x2 and 3x3 cm2 field sizes (FSs) (normalized to 10x10 cm2 FS), with their own treatment planning system (TPS) and the energy clinically used for stereotactic body radiation therapy delivery. OFs were calculated for each combination of grid resolution (GR) (1, 2 and 3 mm) and ST and finally compared with the OFs measured for the TPS commissioning. A multivariate analysis was performed to test the effect of basic plan parameters on calculated OFs. Results A total of 509 data points were collected. Calculated OFs are slightly higher than measured ones. The multivariate analysis showed that Center, GR, algorithm type, and FS are predictive variables of the difference between calculated and measured OFs (p Conclusions Modern TPSs slightly overestimate the calculated small field OFs compared with measured ones. Grid resolution, algorithm, center number and field size influence the calculation of small field OFs.
Databáze: OpenAIRE
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