Citation
García Vázquez, Verónica and Marinetto, Eugenio and Guerra Gutiérrez, Pedro and Valdivieso Casique, Manlio Fabio and Calvo Manuel, Felipe Ángel and Alvarado Vásquez, Eduardo and Solé Pesutic, Claudio Vicente and Vosburgh, Kirby Gannett and Desco Menéndez, Manuel and Pascau González-Garzón, Javier
(2017).
Assessment of intraoperative 3D imaging alternatives for IOERT dose estimation.
"Zeitschrift für Medizinische Physik", v. 27
(n. 3);
pp. 218-231.
ISSN 0939-3889.
https://doi.org/10.1016/j.zemedi.2016.07.002.
Abstract
Intraoperative electron radiation therapy (IOERT) involves irradiation of an unresected tumour or a post-resection tumour bed. The dose distribution is calculated from a preoperative computed tomography (CT) study acquired using a CT simulator. However, differences between the actual IOERT field and that calculated from the preoperative study arise as a result of patient position, surgical access, tumour resection and the IOERT set-up. Intraoperative CT imaging may then enable a more accurate estimation of dose distribution. In this study, we evaluated three kilovoltage (kV) CT scanners with the ability to acquire intraoperative images. Our findings indicate that current IOERT plans may be improved using data based on actual anatomical conditions during radiation. The systems studied were two portable systems (“O-arm”, a cone-beam CT [CBCT] system, and “BodyTom”, a multislice CT [MSCT] system) and one CBCT integrated in a conventional linear accelerator (LINAC) (“TrueBeam”). TrueBeam and BodyTom showed good results, as the gamma pass rates of their dose distributions compared to the gold standard (dose distributions calculated from images acquired with a CT simulator) were above 97% in most cases. The O-arm yielded a lower percentage of voxels fulfilling gamma criteria owing to its reduced field of view (which left it prone to truncation artefacts). Our results show that the images acquired using a portable CT or even a LINAC with on-board kV CBCT could be used to estimate the dose of IOERT and improve the possibility to evaluate and register the treatment administered to the patient.