Journal: Physics in medicine and biology

Article Title: Improvement in Sampling and Modulation of Multiplexing with Temporal Shuttering of Adaptable Apertures in a Brain-Dedicated Multi-Pinhole SPECT System

doi: 10.1088/1361-6560/abd5cd

Figure Lengend Snippet: Pixel-based and count-based MUX for the simulated acquisition schemes with solely the axial apertures (i.e., A(100%)) with 4 different MUX levels for the Defrise and brain perfusion phantoms.

Article Snippet: This phantom is a customized version of Defrise Insert Model ECT/DEF/I from Data Spectrum Corporation, Durham, NC, USA ( https://www.spect.com ).

Techniques:

Journal: Physics in medicine and biology

Article Title: Improvement in Sampling and Modulation of Multiplexing with Temporal Shuttering of Adaptable Apertures in a Brain-Dedicated Multi-Pinhole SPECT System

doi: 10.1088/1361-6560/abd5cd

Figure Lengend Snippet: (A) The middle coronal slice of the ground truth and the reconstructed images of the Defrise phantom with the base geometry (i.e., C(100%)), axial-only (i.e., A(100%)), and combination of both the central and axial apertures with the same time share (i.e., C(50%)-A(50%)) acquisition schemes at the 4 MUX levels. The image voxels beyond the radius of 110 mm from the imaging VOI center were set to zero for all the shown images including the ground truth. The shown slices correspond to iteration 100 and are normalized for display by their peak values. (B)–(E) The CRF values for the reconstructed images of the Defrise phantom over iterations for C(100%), A(100%), and C(50%)-A(50%) schemes at MUX levels 1–4, respectively. (F) The peak CRF value (at iteration 100) for C(50%)-A(50%) scheme at MUX levels 1–4.

Article Snippet: This phantom is a customized version of Defrise Insert Model ECT/DEF/I from Data Spectrum Corporation, Durham, NC, USA ( https://www.spect.com ).

Techniques: Imaging

Journal: IEEE transactions on medical imaging

Article Title: Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

doi: 10.1109/TMI.2020.3015079

Figure Lengend Snippet: (a) Transverse view of the hot-rod activity phantom designed for evaluation of angular sampling. (b) Mid-coronal view of the Defrise phantom with 11 solid and 10 hot disks customized based on Defrise Insert™ Model ECT/DEF/I (Data Spectrum Corporation, Durham, NC, USA) to evaluate axial sampling. Notice that herein we refer to the activity-filled gaps between the solid disks as hot disks.

Article Snippet: An attenuation coefficient equivalent to that of water for 123 I (μ=0.147 cm −1 for 159 keV) was employed for the cylindrical container in simulation and reconstruction. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Fig. 2. caption a7 (a) Transverse view of the hot-rod activity phantom designed for evaluation of angular sampling. (b) Mid-coronal view of the Defrise phantom with 11 solid and 10 hot disks customized based on Defrise InsertTM Model ECT/DEF/I (Data Spectrum Corporation, Durham, NC, USA) to evaluate axial sampling.

Techniques: Activity Assay, Sampling

Journal: IEEE transactions on medical imaging

Article Title: Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

doi: 10.1109/TMI.2020.3015079

Figure Lengend Snippet: (a) The mid-coronal slice of the Defrise phantoms ground truth image and the corresponding reconstructed slices of the phantom at the iteration-of-interest for the current prototype design of the AdaptiSPECT-C with a stationary scan (one axial position), and with two (4.6 cm step) and three axial positions (3.1 cm steps). (b) The summed axial profile of the Defrise reconstructed images for the three data acquisition schemes obtained by representing each transverse slice by sum of its voxels. (c) The NRMSE values at the iteration-of-interest for the three data acquisition schemes. Note although the original Defrise phantom used in the simulation is cylindrical, the phantom was down-sampled to the dimensions of the reconstructed image and then image trimming was applied (as described in section II.D) to generate the ground truth image in (a) matching the reconstructed images. The axial sampling positions with stationary scan are shown by the green arrows in (b). The axial sampling position corresponding to the QV ring with stationary scan is beyond the axial extent of the phantom and reconstructed image. The axial sampling positions added to the ones of stationary scan with two- and three-axial-position scans because of the imaging bed translation are shown by the blue and orange arrows, respectively, in (b). Although an axial sampling is added near the farthest disk at the cranial region (the rightest region in (b)) with two- and three-axial-position scans, the disk couldnt be distinguished because of the truncation happens in that region with the imaging bed translation. Notice the improved visibility of the disks and NRMSE improvement in the Defrise phantom with increase of axial sampling.

Article Snippet: An attenuation coefficient equivalent to that of water for 123 I (μ=0.147 cm −1 for 159 keV) was employed for the cylindrical container in simulation and reconstruction. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Fig. 2. caption a7 (a) Transverse view of the hot-rod activity phantom designed for evaluation of angular sampling. (b) Mid-coronal view of the Defrise phantom with 11 solid and 10 hot disks customized based on Defrise InsertTM Model ECT/DEF/I (Data Spectrum Corporation, Durham, NC, USA) to evaluate axial sampling.

Techniques: Sampling, Imaging

Journal: IEEE transactions on medical imaging

Article Title: Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

doi: 10.1109/TMI.2020.3015079

Figure Lengend Snippet: (a) The mid-coronal slice of the Defrise phantoms ground truth image and the corresponding reconstructed slices at the iteration-of-interest with and without the QV ring of detector heads. (b) The summed axial profile of the Defrise reconstructed images with and without the QV ring of the detector heads obtained by summing the voxels over non-axial directions (x and y). Note the axial position of the QV ring of the detector heads is toward the top (end) of the shown images (plot). (c) Sample transverse and mid-coronal slices of the reconstructed images of the hot-rod phantom with and without the QV ring of the detector heads. The axial position of the transverse slices is shown on the coronal slices by red arrows. (d) The mid-horizontal profile of the axially summed slices of the hot-rod phantom over the caudal and cranial hemispheres with and without the QV ring. The caudal and cranial hemispheres are shown by green and yellow dashed regions, respectively, on coronal slices in (c).

Article Snippet: An attenuation coefficient equivalent to that of water for 123 I (μ=0.147 cm −1 for 159 keV) was employed for the cylindrical container in simulation and reconstruction. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Fig. 2. caption a7 (a) Transverse view of the hot-rod activity phantom designed for evaluation of angular sampling. (b) Mid-coronal view of the Defrise phantom with 11 solid and 10 hot disks customized based on Defrise InsertTM Model ECT/DEF/I (Data Spectrum Corporation, Durham, NC, USA) to evaluate axial sampling.

Techniques: