| 1. |
- Fan, Peng, et al.
(författare)
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Scatter and crosstalk corrections for (99m)Tc/(123)I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators.
- 2015
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Ingår i: Medical Physics. - : Wiley. - 0094-2405 .- 2473-4209. ; 42:12, s. 6895-6911
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Tidskriftsartikel (refereegranskat)abstract
- The energy spectrum for a cadmium zinc telluride (CZT) detector has a low energy tail due to incomplete charge collection and intercrystal scattering. Due to these solid-state detector effects, scatter would be overestimated if the conventional triple-energy window (TEW) method is used for scatter and crosstalk corrections in CZT-based imaging systems. The objective of this work is to develop a scatter and crosstalk correction method for (99m)Tc/(123)I dual-radionuclide imaging for a CZT-based dedicated cardiac SPECT system with pinhole collimators (GE Discovery NM 530c/570c).
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| 2. |
- Ljungberg, Michael, et al.
(författare)
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Monte Carlo simulations of the GE discovery alcyone CZT SPECT system
- 2016
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Ingår i: 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014. - 9781479960972
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Konferensbidrag (refereegranskat)abstract
- Compact SPECT systems with cadmium zinc telluride (CZT) solid-state detectors with improved energy resolution and shorter acquisition times have recently been introduced. These systems have, however, different energy characteristics compared to NaI(Tl) crystal-based cameras. There is therefore a need to develop new simulation models for these cameras. We modeled the charge transport within the CZT detectors for a GE Discovery 530c/570c SPECT system with multiple pinhole collimators employing the SIMIND Monte Carlo program and validated simulations against measurements. The incomplete charge collection between the anode and cathode in the pixilated CZT was modeled with the Hecht equation. The simulation also included charge-sharing effects across pixels due to physical interactions and charge diffusion. To validate our CZT-model 99mTc and 123I point sources and a 201Tl line source were acquired and measured energy spectra were compared with simulated energy spectra. The Monte Carlo simulated energy spectra agreed well with the experimental measurements within the photopeak, overestimated the k-edge x-ray escape peaks of Cd and Te, and slightly underestimated the remainder of the tail. Comparisons for a cardiac insert with a defect in an elliptical Data Spectrum phantom were also performed. Here, simulated projections were read into the GE Xeleris system for reconstruction. We found good agreement in image reconstruction visually. We conclude that it is feasible to simulate CZT detectors with good agreement using the SIMIND code.
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| 3. |
- Ljungberg, Michael, et al.
(författare)
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Nuclear medicine : Physics and instrumentation special feature review article: SPECT/CT: An update on technological developments and clinical applications
- 2018
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Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 91:1081
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Forskningsöversikt (refereegranskat)abstract
- Functional nuclear medicine imaging with single-photon emission CT (SPECT) in combination with anatomical CT has been commercially available since the beginning of this century. The combination of the two modalities has improved both the sensitivity and specificity of many clinical applications and CT in conjunction with SPECT that allows for spatial overlay of the SPECT data on good anatomy images. Introduction of diagnostic CT units as part of the SPECT/CT system has also potentially allowed for a more cost-efficient use of the equipment. Most of the SPECT systems available are based on the well-known Anger camera principle with Nal(TI) as a scintillation material, parallel-hole collimators and multiple photomultiplier tubes, which, from the centroid of the scintillation light, determine the position of an event. Recently, solid-state detectors using cadmium-zinc-Telluride became available and clinical SPECT cameras employing multiple pinhole collimators have been developed and introduced in the market. However, even if new systems become available with better hardware, the SPECT reconstruction will still be affected by photon attenuation and scatter and collimator response. Compensation for these effects is needed even for qualitative studies to avoid artefacts leading to false positives. This review highlights ):he recent progress for both new SPECT cameras systems as well as for various data-processing and compensation methods.
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| 4. |
- Pretorius, P. Hendrik, et al.
(författare)
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Monte Carlo Simulations of the GE Discovery Alcyone CZT SPECT Systems
- 2015
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 62:3, s. 832-839
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Tidskriftsartikel (refereegranskat)abstract
- Compact SPECT systems with cadmium zinc telluride (CZT) solid-state detectors with improved energy resolution and shorter acquisition times have recently been introduced. These systems have, however, different energy characteristics compared to NaI(Tl) crystal-based cameras; therefore, a need exists to develop new simulation models for these cameras. We modeled the charge transport within the CZT detectors for a GE Discovery 530c/570c SPECT system with multiple pinhole collimators employing the SIMIND Monte Carlo program and validated simulations against measurements. The incomplete charge collection between the anode and cathode in the pixilated CZT was modeled with the Hecht equation. The simulation also included charge-sharing effects across pixels due to physical interactions and charge diffusion. To validate our CZT-model, Tc-99m and I-123 point sources and a Tl-201 line source were acquired and measured. Measured energy spectra were compared with simulated energy spectra. The Monte Carlo simulated energy spectra agreed well with the experimental measurements within the photopeak, overestimated the k-edge x-ray escape peaks of cadmium and telluride, and slightly underestimated the remainder of the tail. Comparisons of system sensitivity and spatial resolution were also conducted for an array of point source locations with results showing excellent agreement. Lastly, to demonstrate a clinically realistic case, a simulation of an anthropomorphic phantom with a cardiac insert and an inferior defect was performed. Simulated projections were processed using the GE Xeleris software confirming the accuracy of the SIMIND geometry. We conclude that it is feasible to simulate the GE Discovery 530c/570c SPECT system using the SIMIND code.
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