Purpose: To develop and test an integrated simulation system based on the digital Extended Cardio Torso (XCAT) phantom for 4-dimensional (4D) radiation therapy of lung cancer. Methods: A computer program was developed...Purpose: To develop and test an integrated simulation system based on the digital Extended Cardio Torso (XCAT) phantom for 4-dimensional (4D) radiation therapy of lung cancer. Methods: A computer program was developed to facilitate the characterization and implementation of the XCAT phantom for 4D radiation therapy applications. To verify that patient-specific motion trajectories are reproducible with the XCAT phantom, motion trajectories of the diaphragm and chest were extracted from previously acquired MRI scans of five subjects and were imported into the XCAT phantom. The input versus the measured trajectories was compared. Simulation methods of 4D-CT and 4D-cone-beam CT (CBCT) based on the XCAT phantom were developed and tested for regular and irregular respiratory patterns. Simulation of 4D dose delivery was illustrated in a simulated lung stereotactic-body radiation therapy (SBRT) case based on the XCAT phantom. Dosimetric comparison was performed between the planned dose and simulated delivered dose. Result: The overall mean (±standard deviation) difference in motion amplitude between the input and measured trajectories was 1.19 (±0.79) mm for the XCAT phantoms with voxel size of 2 mm. 4D-CT and 4D-CBCT images simulated based on the XCAT phantom were validated using regular respiratory patterns and tested for irregular respiratory patterns. Comparison between simulated 4D dose delivery and planned dose for the lung SBRT case showed comparable results in all dosimetric matrices: the relative differences were 0.3%, 4.0%, 0%, and 2.8%, respectively, for max cord dose, max esophagus dose, mean heart dose, and V20Gy of the lungs. 97.5% of planning target volume (PTV) received prescription dose in the simulated 4D delivery, as compared to 95% of PTV received prescription dose in the plan. Conclusion: We developed an integrated simulation system based on the XCAT digital phantom and illustrated its utility in 4D radiation therapy of lung cancer. This simulation system is potentially a useful tool for quality control and development of imaging and treatment techniques for 4D radiation therapy of lung cancer.展开更多
This study presents a unified framework,systematically shows a detailed visual representation and emphasizes the understanding via various key factors throughout physical-chemical-biological stages underlying the irra...This study presents a unified framework,systematically shows a detailed visual representation and emphasizes the understanding via various key factors throughout physical-chemical-biological stages underlying the irradiation process in FLASH radiotherapy(FLASH-RT)from the review of previous published studies.To develop this framework,we pay close attention to the time scale of irradiation process,to incorporated methodologies from current hypotheses documented by in vitro and vivo studies.Concurrently,the framework illustrates the potential differences in tumor and normal cells induced by FLASH-RT.This synthesis of the literature reveals the potential research points in existing hypotheses which lack of consideration on the entire responses and interactions of each stage from initial physical to biological process.Our interpretation provides both a structured overview and a conceptual explanation,facilitating current understanding and further investigation that could be validated in future experimental settings in FLASH-RT research.展开更多
To the Editor:Due to the highly complex nature of intensity-modulated radiotherapy(IMRT)planning and delivery,patient specific quality assurance(PSQA)should be implemented to assure the reliability of treatment delive...To the Editor:Due to the highly complex nature of intensity-modulated radiotherapy(IMRT)planning and delivery,patient specific quality assurance(PSQA)should be implemented to assure the reliability of treatment delivery and improve the treatment efficacy.展开更多
Purpose:Motion artifacts induced by breathing variations are common in 4D-MRI images.This study aims to reduce the motion artifacts by developing a novel,robust 4D-MRI sorting method based on anatomic feature matching...Purpose:Motion artifacts induced by breathing variations are common in 4D-MRI images.This study aims to reduce the motion artifacts by developing a novel,robust 4D-MRI sorting method based on anatomic feature matching and applicable in both cine and sequential acquisition.Method:The proposed method uses the diaphragm as the anatomic feature to guide the sorting of 4D-MRI images.Initially,both abdominal 2D sagittal cine MRI images and axial MRI images were acquired.The sagittal cine MRI images were divided into 10 phases as ground truth.Next,the phase of each axial MRI image is determined by matching its diaphragm position in the intersection plane to the ground truth cine MRI.Then,those matched phases axial images were sorted into 10-phase bins which were identical to the ground truth cine images.Finally,10-phase 4D-MRI were reconstructed from these sorted axial images.The accuracy of reconstructed 4D-MRI data was evaluated by comparing with the ground truth using the 4D eXtended Cardiac Torso(XCAT)digital phantom.The effects of breathing signal,including both regular(cosine function)and irregular(patient data)in both axial cine and sequential scanning modes,on reconstruction accuracy were investigated by calculating total relative error(TRE)of the 4D volumes,Volume-Percent-Difference(VPD)and Center-of-Mass-Shift(COMS)of the estimated tumor volume,compared with the ground truth XCAT images.Results:In both scanning modes,reconstructed 4D-MRI images matched well with ground truth with minimal motion artifacts.The averaged TRE of the 4D volume,VPD and COMS of the EOE phase in both scanning modes are 0.32%/1.20%/0.05 mm for regular breathing,and 1.13%/4.26%/0.21 mm for patient irregular breathing.Conclusion:The preliminary evaluation results illustrated the feasibility of the robust 4D-MRI sorting method based on anatomic feature matching.This method provides improved image quality with reduced motion artifacts for both cine and sequential scanning modes.展开更多
文摘Purpose: To develop and test an integrated simulation system based on the digital Extended Cardio Torso (XCAT) phantom for 4-dimensional (4D) radiation therapy of lung cancer. Methods: A computer program was developed to facilitate the characterization and implementation of the XCAT phantom for 4D radiation therapy applications. To verify that patient-specific motion trajectories are reproducible with the XCAT phantom, motion trajectories of the diaphragm and chest were extracted from previously acquired MRI scans of five subjects and were imported into the XCAT phantom. The input versus the measured trajectories was compared. Simulation methods of 4D-CT and 4D-cone-beam CT (CBCT) based on the XCAT phantom were developed and tested for regular and irregular respiratory patterns. Simulation of 4D dose delivery was illustrated in a simulated lung stereotactic-body radiation therapy (SBRT) case based on the XCAT phantom. Dosimetric comparison was performed between the planned dose and simulated delivered dose. Result: The overall mean (±standard deviation) difference in motion amplitude between the input and measured trajectories was 1.19 (±0.79) mm for the XCAT phantoms with voxel size of 2 mm. 4D-CT and 4D-CBCT images simulated based on the XCAT phantom were validated using regular respiratory patterns and tested for irregular respiratory patterns. Comparison between simulated 4D dose delivery and planned dose for the lung SBRT case showed comparable results in all dosimetric matrices: the relative differences were 0.3%, 4.0%, 0%, and 2.8%, respectively, for max cord dose, max esophagus dose, mean heart dose, and V20Gy of the lungs. 97.5% of planning target volume (PTV) received prescription dose in the simulated 4D delivery, as compared to 95% of PTV received prescription dose in the plan. Conclusion: We developed an integrated simulation system based on the XCAT digital phantom and illustrated its utility in 4D radiation therapy of lung cancer. This simulation system is potentially a useful tool for quality control and development of imaging and treatment techniques for 4D radiation therapy of lung cancer.
基金supported by a research grant DKU Distinguish Scholarship Project(202201),China.
文摘This study presents a unified framework,systematically shows a detailed visual representation and emphasizes the understanding via various key factors throughout physical-chemical-biological stages underlying the irradiation process in FLASH radiotherapy(FLASH-RT)from the review of previous published studies.To develop this framework,we pay close attention to the time scale of irradiation process,to incorporated methodologies from current hypotheses documented by in vitro and vivo studies.Concurrently,the framework illustrates the potential differences in tumor and normal cells induced by FLASH-RT.This synthesis of the literature reveals the potential research points in existing hypotheses which lack of consideration on the entire responses and interactions of each stage from initial physical to biological process.Our interpretation provides both a structured overview and a conceptual explanation,facilitating current understanding and further investigation that could be validated in future experimental settings in FLASH-RT research.
基金National Key Research and Development Program of China(Nos.2021YFE0202500 and 2019YFF01014403)Beijing Municipal Commission of Science and Technology Collaborative Innovation Project(No.Z221100003522028)+1 种基金the National Natural Science Foundation of China(Nos.11735003,11975041,and 11961141004)the fundamental Research Funds for the Central Universities.
文摘To the Editor:Due to the highly complex nature of intensity-modulated radiotherapy(IMRT)planning and delivery,patient specific quality assurance(PSQA)should be implemented to assure the reliability of treatment delivery and improve the treatment efficacy.
基金This research was partly supported by research grants(NIH R01 EB028324,NIH R01 CA226899,GRF 151021/18M,GRF 151022/19M and HMRF 06173276).
文摘Purpose:Motion artifacts induced by breathing variations are common in 4D-MRI images.This study aims to reduce the motion artifacts by developing a novel,robust 4D-MRI sorting method based on anatomic feature matching and applicable in both cine and sequential acquisition.Method:The proposed method uses the diaphragm as the anatomic feature to guide the sorting of 4D-MRI images.Initially,both abdominal 2D sagittal cine MRI images and axial MRI images were acquired.The sagittal cine MRI images were divided into 10 phases as ground truth.Next,the phase of each axial MRI image is determined by matching its diaphragm position in the intersection plane to the ground truth cine MRI.Then,those matched phases axial images were sorted into 10-phase bins which were identical to the ground truth cine images.Finally,10-phase 4D-MRI were reconstructed from these sorted axial images.The accuracy of reconstructed 4D-MRI data was evaluated by comparing with the ground truth using the 4D eXtended Cardiac Torso(XCAT)digital phantom.The effects of breathing signal,including both regular(cosine function)and irregular(patient data)in both axial cine and sequential scanning modes,on reconstruction accuracy were investigated by calculating total relative error(TRE)of the 4D volumes,Volume-Percent-Difference(VPD)and Center-of-Mass-Shift(COMS)of the estimated tumor volume,compared with the ground truth XCAT images.Results:In both scanning modes,reconstructed 4D-MRI images matched well with ground truth with minimal motion artifacts.The averaged TRE of the 4D volume,VPD and COMS of the EOE phase in both scanning modes are 0.32%/1.20%/0.05 mm for regular breathing,and 1.13%/4.26%/0.21 mm for patient irregular breathing.Conclusion:The preliminary evaluation results illustrated the feasibility of the robust 4D-MRI sorting method based on anatomic feature matching.This method provides improved image quality with reduced motion artifacts for both cine and sequential scanning modes.
