Surface scanning for 3D dose calculation in intraoperative electron radiation therapy
García-Vázquez V (1), Sesé-Lucio B (2), Calvo FA (2,3,4,5), Vaquero JJ (2,6), Desco M (2,6,7,8), Pascau J (2,6,7).
(1) Hospital General Universitario Gregorio Marañón, Unidad de Medicina y Cirugía Experimental (Instituto de Investigación Sanitaria Gregorio Marañón), Madrid, Spain.
(2) Hospital General Universitario Gregorio Marañón, Unidad de Medicina y Cirugía Experimental (Instituto de Investigación Sanitaria Gregorio Marañón), Madrid, Spain.
(3) Departamento de Oncología, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
(4) Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.
(5) Clínica Universidad de Navarra, Madrid, Spain.
(6) Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain.
(7) Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.
(8) Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain.
Dose calculations in intraoperative electron radiation therapy (IOERT) rely on the conventional assumption of water-equivalent tissues at the applicator end, which defines a flat irradiation surface. However, the shape of the irradiation surface modifies the dose distribution. Our study explores, for the first time, the use of surface scanning methods for three-dimensional dose calculation of IOERT.
Two different three-dimensional scanning technologies were evaluated in a simulated IOERT scenario: a tracked conoscopic holography sensor (ConoProbe) and a structured-light three-dimensional scanner (Artec). Dose distributions obtained from computed tomography studies of the surgical field (gold standard) were compared with those calculated under the conventional assumption or from pseudo-computed tomography studies based on surfaces.
In the simulated IOERT scenario, the conventional assumption led to an average gamma pass rate of 39.9% for dose values greater than 10% (two configurations, with and without blood in the surgical field). Results improved when considering surfaces in the dose calculation (88.5% for ConoProbe and 92.9% for Artec).
More accurate three-dimensional dose distributions were obtained when considering surfaces in the dose calculation of the simulated surgical field. The structured-light three-dimensional scanner provided the best results in terms of dose distributions. The findings obtained in this specific experimental setup warrant further research on surface scanning in the IOERT context owing to the clinical interest of improving the documentation of the actual IOERT scenario.
CITATION Radiat Oncol. 2018 Dec 7;13(1):243. doi: 10.1186/s13014-018-1181-0