Reducing 4D CT imaging artifacts at the source: first experimental results from the respiratory adaptive computed tomography (REACT) system
Access status:
Open Access
Type
ArticleAuthor/s
Morton, NatashaSykes, Jonathan
Barber, Jeffrey
Hofmann, Christian
Keall, Paul
O'Brien, Ricky
Abstract
Breathing variations during 4D CT imaging often manifest as geometric irregularities known as respiratory-induced image artifacts and ultimately effect radiotherapy treatment efficacy. To reduce such image artifacts we developed Respiratory Adaptive Computed Tomography (REACT) to ...
See moreBreathing variations during 4D CT imaging often manifest as geometric irregularities known as respiratory-induced image artifacts and ultimately effect radiotherapy treatment efficacy. To reduce such image artifacts we developed Respiratory Adaptive Computed Tomography (REACT) to trigger CT acquisition during periods of regular breathing. For the first time, we integrate REACT with clinical hardware and hypothesize that REACT will reduce respiratory-induced image artifacts ≥ 4 mm compared to conventional 4D CT. 4D image sets were acquired using REACT and conventional 4D CT on a Siemens Somatom scanner. Scans were taken for 13 respiratory traces (12 patients) that were reproduced on a lung-motion phantom. Motion was observed by the Varian RPM system and sent to the REACT software where breathing irregularity was evaluated in real-time and used to trigger the imaging beam. REACT and conventional 4D CT images were compared to a ground truth static-phantom image and compared for absolute geometric differences within the region-of-interest. Breathing irregularity during imaging was retrospectively assessed using the root-mean-square error of the RPM measured respiratory signal during beam on (RMSE_Beam_on) for each phase of the respiratory cycle. REACT significantly reduced the average frequency of respiratory-induced image artifacts ≥ 4 mm by 70% for the tumor (p = 0.003) and 76% for the lung (p = 0.0002) compared to conventional 4D CT. Volume reductions of 10% to 6% of the tumor and 2% to 1% of the lung compared to conventional 4D CT were seen. Breathing irregularity during imaging (RMSE_Beam_on) was significantly reduced by 27% (p = 0.013) using the REACT method. For the first time, REACT was successfully integrated with clinical hardware. Our findings support the hypothesis that REACT significantly reduced respiratory-induced image artifacts compared to conventional 4D CT. These experimental results provide compelling evidence for further REACT investigation, potentially providing clearer images for clinical use.
See less
See moreBreathing variations during 4D CT imaging often manifest as geometric irregularities known as respiratory-induced image artifacts and ultimately effect radiotherapy treatment efficacy. To reduce such image artifacts we developed Respiratory Adaptive Computed Tomography (REACT) to trigger CT acquisition during periods of regular breathing. For the first time, we integrate REACT with clinical hardware and hypothesize that REACT will reduce respiratory-induced image artifacts ≥ 4 mm compared to conventional 4D CT. 4D image sets were acquired using REACT and conventional 4D CT on a Siemens Somatom scanner. Scans were taken for 13 respiratory traces (12 patients) that were reproduced on a lung-motion phantom. Motion was observed by the Varian RPM system and sent to the REACT software where breathing irregularity was evaluated in real-time and used to trigger the imaging beam. REACT and conventional 4D CT images were compared to a ground truth static-phantom image and compared for absolute geometric differences within the region-of-interest. Breathing irregularity during imaging was retrospectively assessed using the root-mean-square error of the RPM measured respiratory signal during beam on (RMSE_Beam_on) for each phase of the respiratory cycle. REACT significantly reduced the average frequency of respiratory-induced image artifacts ≥ 4 mm by 70% for the tumor (p = 0.003) and 76% for the lung (p = 0.0002) compared to conventional 4D CT. Volume reductions of 10% to 6% of the tumor and 2% to 1% of the lung compared to conventional 4D CT were seen. Breathing irregularity during imaging (RMSE_Beam_on) was significantly reduced by 27% (p = 0.013) using the REACT method. For the first time, REACT was successfully integrated with clinical hardware. Our findings support the hypothesis that REACT significantly reduced respiratory-induced image artifacts compared to conventional 4D CT. These experimental results provide compelling evidence for further REACT investigation, potentially providing clearer images for clinical use.
See less
Date
2020Source title
Physics in Medicine & BiologyVolume
65Issue
7Publisher
IOP SciencesLicence
Copyright All Rights ReservedFaculty/School
Faculty of Medicine and HealthDepartment, Discipline or Centre
Central Clinical SchoolShare