PURPOSE: Commonly 2D scouts or topograms are used prior to CT scan acquisition. However, low-dose 3D scouts could potentially provide additional information for more effective patient positioning and selection of acquisition protocols. We propose using model-based iterative reconstruction to reconstruct low exposure tomographic data to maintain image quality in both low-dose 3D scouts and reprojected topograms based on those 3D scouts. METHODS: We performed tomographic acquisitions on a CBCT test-bench using a range of exposure settings from 16.6 to 231.9 total mAs. Both an anthropomorphic phantom and a 32 cm CTDI phantom were scanned. The penalized-likelihood reconstructions were made using Matlab and CUDA libraries and reconstruction parameters were tuned to determine the best regularization strength and delta parameter. RMS error between reconstructions and the highest exposure reconstruction were computed, and CTDIW values were reported for each exposure setting. RMS error for reprojected topograms were also computed. RESULTS: We find that we are able to produce low-dose (0.417 mGy) 3D scouts that show high-contrast and large anatomical features while maintaining the ability to produce traditional topograms. CONCLUSIONS: We demonstrated that iterative reconstruction can mitigate noise in very low exposure CT acquisitions to enable 3D CT scout. Such additional 3D information may lead to improved protocols for patient positioning and acquisition refinements as well as a number of advanced dose reduction strategies that require localization of anatomical features and quantities that are not provided by simple 2D topograms.
PURPOSE: Commonly 2D scouts or topograms are used prior to CT scan acquisition. However, low-dose 3D scouts could potentially provide additional information for more effective patient positioning and selection of acquisition protocols. We propose using model-based iterative reconstruction to reconstruct low exposure tomographic data to maintain image quality in both low-dose 3D scouts and reprojected topograms based on those 3D scouts. METHODS: We performed tomographic acquisitions on a CBCT test-bench using a range of exposure settings from 16.6 to 231.9 total mAs. Both an anthropomorphic phantom and a 32 cm CTDI phantom were scanned. The penalized-likelihood reconstructions were made using Matlab and CUDA libraries and reconstruction parameters were tuned to determine the best regularization strength and delta parameter. RMS error between reconstructions and the highest exposure reconstruction were computed, and CTDIW values were reported for each exposure setting. RMS error for reprojected topograms were also computed. RESULTS: We find that we are able to produce low-dose (0.417 mGy) 3D scouts that show high-contrast and large anatomical features while maintaining the ability to produce traditional topograms. CONCLUSIONS: We demonstrated that iterative reconstruction can mitigate noise in very low exposure CT acquisitions to enable 3D CT scout. Such additional 3D information may lead to improved protocols for patient positioning and acquisition refinements as well as a number of advanced dose reduction strategies that require localization of anatomical features and quantities that are not provided by simple 2D topograms.
Authors: Lifeng Yu; Yu Zou; Emil Y Sidky; Charles A Pelizzari; Peter Munro; Xiaochuan Pan Journal: IEEE Trans Med Imaging Date: 2006-07 Impact factor: 10.048
Authors: Zhye Yin; Yangyang Yao; Albert Montillo; Mingye Wu; Peter M Edic; Mannudeep Kalra; Bruno De Man Journal: Med Phys Date: 2015-05 Impact factor: 4.071
Authors: Adam S Wang; J Webster Stayman; Yoshito Otake; Sebastian Vogt; Gerhard Kleinszig; Jeffrey H Siewerdsen Journal: Med Phys Date: 2015-05 Impact factor: 4.071
Authors: Mannudeep K Kalra; Michael M Maher; Thomas L Toth; Bernhard Schmidt; Bryan L Westerman; Hugh T Morgan; Sanjay Saini Journal: Radiology Date: 2004-10-21 Impact factor: 11.105