Vikas Gupta1, Yibing Wang2, Alejandra Méndez Romero2, Andriy Myronenko3, Petr Jordan3, Calvin Maurer3, Ben Heijmen2, Mischa Hoogeman2. 1. Department of Radiation Oncology, Erasmus MC Cancer Institute, Groene Hilledijk 301, Rotterdam 3075 EA, The Netherlands; Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Sweden; Center for Medical Imaging and Visualization (CMIV), Department of Medical and Health Sciences, Linköping University, Sweden. Electronic address: v.gupta@erasmusmc.nl. 2. Department of Radiation Oncology, Erasmus MC Cancer Institute, Groene Hilledijk 301, Rotterdam 3075 EA, The Netherlands. 3. Accuray Incorporated, 1310 Chesapeake Terrace, Sunnyvale, CA 94089, USA.
Abstract
PURPOSE: To validate a novel deformable image registration (DIR) method for online adaptation of planning organ-at-risk (OAR) delineations to match daily anatomy during hypo-fractionated RT of abdominal tumors. MATERIALS AND METHODS: For 20 liver cancer patients, planning OAR delineations were adapted to daily anatomy using the DIR on corresponding repeat CTs. The DIR's accuracy was evaluated for the entire cohort by comparing adapted and expert-drawn OAR delineations using geometric (Dice Similarity Coefficient (DSC), Modified Hausdorff Distance (MHD) and Mean Surface Error (MSE)) and dosimetric (Dmax and Dmean) measures. RESULTS: For all OARs, DIR achieved average DSC, MHD and MSE of 86%, 2.1 mm, and 1.7 mm, respectively, within 20 s for each repeat CT. Compared to the baseline (translations), the average improvements ranged from 2% (in heart) to 24% (in spinal cord) in DSC, and 25% (in heart) to 44% (in right kidney) in MHD and MSE. Furthermore, differences in dose statistics (Dmax, Dmean and D2%) using delineations from an expert and the proposed DIR were found to be statistically insignificant (p > 0.01). CONCLUSION: The validated DIR showed potential for online-adaptive radiotherapy of abdominal tumors as it achieved considerably high geometric and dosimetric correspondences with the expert-drawn OAR delineations, albeit in a fraction of time required by experts.
PURPOSE: To validate a novel deformable image registration (DIR) method for online adaptation of planning organ-at-risk (OAR) delineations to match daily anatomy during hypo-fractionated RT of abdominal tumors. MATERIALS AND METHODS: For 20 liver cancerpatients, planning OAR delineations were adapted to daily anatomy using the DIR on corresponding repeat CTs. The DIR's accuracy was evaluated for the entire cohort by comparing adapted and expert-drawn OAR delineations using geometric (Dice Similarity Coefficient (DSC), Modified Hausdorff Distance (MHD) and Mean Surface Error (MSE)) and dosimetric (Dmax and Dmean) measures. RESULTS: For all OARs, DIR achieved average DSC, MHD and MSE of 86%, 2.1 mm, and 1.7 mm, respectively, within 20 s for each repeat CT. Compared to the baseline (translations), the average improvements ranged from 2% (in heart) to 24% (in spinal cord) in DSC, and 25% (in heart) to 44% (in right kidney) in MHD and MSE. Furthermore, differences in dose statistics (Dmax, Dmean and D2%) using delineations from an expert and the proposed DIR were found to be statistically insignificant (p > 0.01). CONCLUSION: The validated DIR showed potential for online-adaptive radiotherapy of abdominal tumors as it achieved considerably high geometric and dosimetric correspondences with the expert-drawn OAR delineations, albeit in a fraction of time required by experts.
Authors: Asma Amjad; Jiaofeng Xu; Dan Thill; Colleen Lawton; William Hall; Musaddiq J Awan; Monica Shukla; Beth A Erickson; X Allen Li Journal: Med Phys Date: 2022-02-07 Impact factor: 4.071
Authors: Alba Magallon-Baro; Maaike T W Milder; Patrick V Granton; Wilhelm den Toom; Joost J Nuyttens; Mischa S Hoogeman Journal: Front Oncol Date: 2022-06-08 Impact factor: 5.738