Patricia St-Amant1, William Foster2, Marie-Anne Froment2, Sylviane Aubin2, Marie-Claude Lavallée2, Luc Beaulieu3. 1. Radiation Oncology Department, CHU de Québec-Université Laval, Québec, Québec, Canada; Department of Physics, Physics Engineering and Optic, and Cancer Research Centre, Université Laval, Québec, Québec, Canada; Centre de recherche du CHU de Québec et Axe Oncologie, CHU de Québec-Université Laval, Québec, Québec, Canada. 2. Radiation Oncology Department, CHU de Québec-Université Laval, Québec, Québec, Canada. 3. Radiation Oncology Department, CHU de Québec-Université Laval, Québec, Québec, Canada; Department of Physics, Physics Engineering and Optic, and Cancer Research Centre, Université Laval, Québec, Québec, Canada; Centre de recherche du CHU de Québec et Axe Oncologie, CHU de Québec-Université Laval, Québec, Québec, Canada. Electronic address: luc.beaulieu@phy.ulaval.ca.
Abstract
PURPOSE: To evaluate if the addition of 3D transabdominal ultrasound (3DTAUS) imaging to computed tomography (CT) can improve treatment planning in 3D adaptive brachytherapy when compared with CT-based planning alone, resulting in treatment plans closer to the ones obtained using magnetic resonance imaging (MRI)-based planning. METHODS AND MATERIALS: Five patients with cervical cancer undergoing brachytherapy underwent three imaging modalities: MRI, CT, and CT-3DTAUS. Volumes were delineated by a radiation oncologist and treatment plans were optimized on each imaging modality. To compare treatment plans, the dwell times optimized on MRI were transferred on CT and CT-3DTAUS images and dose parameters were reported on volumes of the receiving imaging modality. The plans optimized on CT and CT-3DTAUS were also copied and evaluated on MRI images. RESULTS: Treatment plans optimized and evaluated on the same imaging modalities were clinically acceptable but statistically different (p < 0.05) from one another. MR-based plans had the highest target coverage (98%) and CT-based plans the lowest (93%). For all treatment plans evaluated on MRI, the target coverage was equivalent. However, a decrease in target coverage (V100) was observed when MR-based plans were applied on CT-3DTAUS (6%) and CT (13%) with p < 0.05. An increase in the rectum/sigmoid dose (D2cc) was observed with both CT-3DTAUS-based (0.6 Gy) and CT-based planning (1 Gy) when compared with MR-based plans, whereas bladder dose stayed similar. CONCLUSIONS: When compared with CT-based planning, the addition of 3DTAUS to CT results in treatment plans closer to MR-based planning. Its use reduces the high-risk clinical target volume overestimation typically observed on CT, improving coverage of the target volume while reducing dose to the organs at risk.
PURPOSE: To evaluate if the addition of 3D transabdominal ultrasound (3DTAUS) imaging to computed tomography (CT) can improve treatment planning in 3D adaptive brachytherapy when compared with CT-based planning alone, resulting in treatment plans closer to the ones obtained using magnetic resonance imaging (MRI)-based planning. METHODS AND MATERIALS: Five patients with cervical cancer undergoing brachytherapy underwent three imaging modalities: MRI, CT, and CT-3DTAUS. Volumes were delineated by a radiation oncologist and treatment plans were optimized on each imaging modality. To compare treatment plans, the dwell times optimized on MRI were transferred on CT and CT-3DTAUS images and dose parameters were reported on volumes of the receiving imaging modality. The plans optimized on CT and CT-3DTAUS were also copied and evaluated on MRI images. RESULTS: Treatment plans optimized and evaluated on the same imaging modalities were clinically acceptable but statistically different (p < 0.05) from one another. MR-based plans had the highest target coverage (98%) and CT-based plans the lowest (93%). For all treatment plans evaluated on MRI, the target coverage was equivalent. However, a decrease in target coverage (V100) was observed when MR-based plans were applied on CT-3DTAUS (6%) and CT (13%) with p < 0.05. An increase in the rectum/sigmoid dose (D2cc) was observed with both CT-3DTAUS-based (0.6 Gy) and CT-based planning (1 Gy) when compared with MR-based plans, whereas bladder dose stayed similar. CONCLUSIONS: When compared with CT-based planning, the addition of 3DTAUS to CT results in treatment plans closer to MR-based planning. Its use reduces the high-risk clinical target volume overestimation typically observed on CT, improving coverage of the target volume while reducing dose to the organs at risk.
Authors: José Richart; Vicente Carmona-Meseguer; Teresa García-Martínez; Antonio Herreros; Antonio Otal; Santiago Pellejero; Ana Tornero-López; José Pérez-Calatayud Journal: Rep Pract Oncol Radiother Date: 2018-07-23
Authors: Winnie Wing Ling Yip; Joyce Siu Yu Wong; Venus Wan Yan Lee; Frank Chi Sing Wong; Stewart Yuk Tung Journal: J Contemp Brachytherapy Date: 2017-10-30