[Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6371 (United States)
[STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom) Cooper, R.J. [MARIARC, University of Liverpool, Liverpool L69 3GE (United Kingdom) Groves, J. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom) Bimson, W.E. Harkness, L.J., E-mail: [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom) Boston, A.J. The results showed that the detector performance is x-ray quantum noise limited at the low exposures used in each view of tomosynthesis, and the temporal performance at high frame rate (up toĪn investigation of the performance of a coaxial HPGe detector operating in a magnetic resonance imaging fieldĮnergy Technology Data Exchange (ETDEWEB) Ghosting is negligible and independent of the frame rate.
#Izen imaging mri ct scan usg xray interventions full#
The first frame lags were 8% and 4%, respectively, for binning and full resolution mode. The detector temporal performance was categorized as lag and ghosting, both of which were measured as a function of x-ray exposure. It was found that DQE at 0.4 mR is only 20% less than that at highest exposure for both detector readout modes. The noise power spectrum (NPS) and detective quantum efficiency (DQE) of the detector were measured with the exposure range of 0.4-6 mR, which is relevant to the low dose used in tomosynthesis. The focal spot blur due to continuous tube travel was measured for different acquisition geometries, and it was found that pixel binning, instead of focal spot blur, dominates the detector modulation transfer function (MTF). The detector can be read out in full resolution or 2x1 binning (binning in the tube travel direction). The system was equipped with an amorphous selenium (a-Se) full field digital mammography detector with pixel size of 85 μm. A prototype breast tomosynthesis system with a nominal angular range of Â☒5 deg. The purpose of the present work is to investigate the detector performance in different operational modes designed for tomosynthesis acquisition, e.g., binning or full resolution readout, the range of view angles, and the number of views N. The low dose and high frame rate pose a tremendous challenge to the imaging performance of digital mammography detectors. Since the total dose to the breast is kept the same as that in regular mammography, the exposure used for each image of tomosynthesis is 1/N. In breast tomosynthesis a rapid sequence of N images is acquired when the x-ray tube sweeps through different angular views with respect to the breast. Imaging performance of an amorphous selenium digital mammography detector in a breast tomosynthesis system The design and theoretical performance of the detector are discussed, and the results of performance measurements are presented. Performance of a thermal imager employing a hybrid pyroelectric detector array with MOSFET readoutĪ thermal imager employing a two-dimensional hybrid array of pyroelectric detectors with MOSFET readout has been built. Consideration should be given to the acquisition mode and HV cycle time used when imaging to ensure adequate imaging performance with reasonable imaging time. The HV cycle time can be increased to improve image quality. The variation in detector performance with acquisition mode has been examined. Image acquisition times, input-output characteristics and contrast-detail curves of this matrix liquid ion-chamber EPID have been measured to examine the variation in imaging performance with acquisition mode. The Oncology Centre of Auckland Hospital recently purchased a Varian PortalVision TM electronic portal imaging device (EPID). International Nuclear Information System (INIS) Image timing and detector performance of a matrix ion-chamber electronic portal imaging device
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