W Zbijewski1, A Sisniega1, J W Stayman1, A Muhit1, G Thawait2, N Packard3, R Senn3, D Yang3, J Yorkston3, J A Carrino2, J H Siewerdsen4. 1. Dept. of Biomedical Engineering, Johns Hopkins University, Baltimore, MD USA 21205. 2. Russell H. Morgan Dept. of Radiology, Johns Hopkins University, Baltimore, MD USA 21287. 3. Carestream Health Inc., Rochester NY. 4. Dept. of Biomedical Engineering, Johns Hopkins University, Baltimore, MD USA 21205 ; Russell H. Morgan Dept. of Radiology, Johns Hopkins University, Baltimore, MD USA 21287.
Abstract
PURPOSE: Clinical performance studies of an extremity cone-beam CT (CBCT) system indicate excellent bone visualization, but point to the need for improvement of soft-tissue image quality. To this end, a rapid Monte Carlo (MC) scatter correction is proposed, and Penalized Likelihood (PL) reconstruction is evaluated for noise management. METHODS: The accelerated MC scatter correction involved fast MC simulation with low number of photons implemented on a GPU (107 photons/sec), followed by Gaussian kernel smoothing in the detector plane and across projection angles. PL reconstructions were investigated for reduction of imaging dose for projections acquired at ~2 mGy. RESULTS: The rapid scatter estimation yielded root-mean-squared-errors of scatter projections of ~15% of peak scatter intensity for 5·106 photons/projection (runtime ~0.5 sec/projection) and 25% improvement in fat-muscle contrast in reconstructions of a cadaveric knee. PL reconstruction largely restored soft-tissue visualization at 2 mGy dose to that of 10 mGy FBP image. CONCLUSION: The combination of rapid (5-10 minutes/scan) MC-based, patient-specific scatter correction and PL reconstruction offers an important means to overcome the current limitations of extremity CBCT in soft-tissue imaging.
PURPOSE: Clinical performance studies of an extremity cone-beam CT (CBCT) system indicate excellent bone visualization, but point to the need for improvement of soft-tissue image quality. To this end, a rapid Monte Carlo (MC) scatter correction is proposed, and Penalized Likelihood (PL) reconstruction is evaluated for noise management. METHODS: The accelerated MC scatter correction involved fast MC simulation with low number of photons implemented on a GPU (107 photons/sec), followed by Gaussian kernel smoothing in the detector plane and across projection angles. PL reconstructions were investigated for reduction of imaging dose for projections acquired at ~2 mGy. RESULTS: The rapid scatter estimation yielded root-mean-squared-errors of scatter projections of ~15% of peak scatter intensity for 5·106 photons/projection (runtime ~0.5 sec/projection) and 25% improvement in fat-muscle contrast in reconstructions of a cadaveric knee. PL reconstruction largely restored soft-tissue visualization at 2 mGy dose to that of 10 mGy FBP image. CONCLUSION: The combination of rapid (5-10 minutes/scan) MC-based, patient-specific scatter correction and PL reconstruction offers an important means to overcome the current limitations of extremity CBCT in soft-tissue imaging.
Authors: A Sisniega; W Zbijewski; A Badal; I S Kyprianou; J W Stayman; J J Vaquero; J H Siewerdsen Journal: Med Phys Date: 2013-05 Impact factor: 4.071
Authors: John A Carrino; Abdullah Al Muhit; Wojciech Zbijewski; Gaurav K Thawait; J Webster Stayman; Nathan Packard; Robert Senn; Dong Yang; David H Foos; John Yorkston; Jeffrey H Siewerdsen Journal: Radiology Date: 2013-11-18 Impact factor: 11.105
Authors: Robyn Melanie Benz; Meritxell Alzamora Garcia; Felix Amsler; Johannes Voigt; Andreas Fieselmann; Anna Lucja Falkowski; Bram Stieltjes; Anna Hirschmann Journal: J Med Imaging (Bellingham) Date: 2018-03-06
Authors: Gaurav K Thawait; Shadpour Demehri; Abdullah AlMuhit; Wojciech Zbijweski; John Yorkston; Filippo Del Grande; Bashir Zikria; John A Carrino; Jeffrey H Siewerdsen Journal: Eur J Radiol Date: 2015-09-12 Impact factor: 3.528
Authors: P Wu; A Sisniega; J W Stayman; W Zbijewski; D Foos; X Wang; N Khanna; N Aygun; R D Stevens; J H Siewerdsen Journal: Med Phys Date: 2020-04-03 Impact factor: 4.071