scholarly journals Resolution improvement and noise reduction in human pinhole SPECT using a multi-ray approach and the SHINE method

2009 ◽  
Vol 48 (04) ◽  
pp. 159-165 ◽  
Author(s):  
C. Vanhove ◽  
M. Defrise ◽  
A. Seret
Keyword(s):  
Noise Reduction ◽  
Spatial Resolution ◽  
Single Photon ◽  
Photon Emission ◽  
Ray Method ◽  
Resolution Recovery ◽  
Reconstruction Process ◽  
Expectation Maximisation ◽  
Additional Noise ◽  
Recovery Technique

Summary Purpose: This work aimed at quantifying the gains in spatial resolution and noise that could be achieved when using resolution modelling based on a multi-ray approach and additionally the Statistical and Heuristic Noise Extraction (SHINE) method in human pinhole single photon emission tomography (PH-SPECT). Methods: PH-SPECT of two line phantoms and one homogeneous cylinder were recorded using parameters suited for studies of the human neck area. They were reconstructed using pinhole dedicated ordered subsets expectation maximisation algorithm including a resolution recovery technique based on 7 or 21 rays. Optionally, the SPECT data were SHINE pre-processed. Transverse and axial full widths at half-maximum (FWHM) were obtained from the line phantoms. The noise was quantified using the coefficient of variation (COV) derived from the uniform phantom. Two human PHSPECT studies of the thyroid (a hot nodule and a very low uptake) were processed with the same algorithms. Results: Depending on the number of iterations, FWHM decreased by 30 to 50% when using the multi-ray approach in the reconstruction process. The SHINE method did not affect the resolution but decreased the COV by at least 20% and by 45% when combined with the multi-ray method. The two human studies illustrated the gain in spatial resolution and the decrease in noise afforded both by the multi-ray reconstruction and the SHINE method. Conclusion: Iterative reconstruction with resolution modelling allows to obtain high resolution human PH-SPECT studies with reduced noise content. The SHINE method affords an additional noise reduction without compromising the resolution.

High-spatial-resolution detection of new single-photon emission sources

SPIE Newsroom ◽  
2016 ◽  
Author(s):  
Luiz H. G. Tizei ◽  
Sophie Meuret ◽  
Romain Bourrellier ◽  
Anna Tararan ◽  
Odile Stéphan ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Sources ◽  
Single Photon Emission

scholarly journals Performance Evaluation of Fifth-Generation Ultra-High-Resolution SPECT System with Two Stationary Detectors and Multi-Pinhole Imaging

2020 ◽  
Author(s):  
Jan V Hoffmann ◽  
Jan P Janssen ◽  
Takayuki Kanno ◽  
Takayuki Shibutani ◽  
Masahisa Onoguchi ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Single Photon ◽  
Photon Emission ◽  
Small Animal ◽  
High Sensitivity ◽  
General Purpose ◽  
Emission Computed Tomography ◽  
High Count ◽  
Spect System

Abstract Background: Small-animal single-photon emission computed tomography (SPECT) systems with multi-pinhole collimation and large stationary detectors have advantages compared to systems with moving small detectors. These systems benefit from less labour-intensive maintenance and quality control as fewer prone parts are moving, higher accuracy for focused scans and maintaining high resolution with increased sensitivity due to focused pinholes on the field of view. This study aims to investigate the performance of a novel ultra-high-resolution scanner with two-detector-configuration (U-SPECT5-E) and to compare its image quality to a conventional micro-SPECT system with three stationary detectors (U-SPECT+).Methods: The new U-SPECT5-E with two stationary detectors was used for acquiring data with 99mTc-filled point source, hot-rod and uniformity phantoms to analyse sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR). Three dedicated multi-pinhole mouse collimators with 75 pinholes each and 0.25-, 0.60- and 1.00-mm pinholes for extra ultra-high resolution (XUHR-M), general-purpose (GP-M) and ultra-high sensitivity (UHS-M) imaging were examined. For CNR analysis, four different activity ranges representing low- and high-count settings were investigated for all three collimators. The experiments for the performance assessment were repeated with the same GP-M collimator in the three-detector U-SPECT+ for comparison. Results: Peak sensitivity was 237 cps/MBq (XUHR-M), 847 cps/MBq (GP-M), 2054 cps/MBq (UHS-M) for U-SPECT5-E and 1710 cps/MBq (GP-M) for U-SPECT+. In the visually analysed sections of the reconstructed mini Derenzo phantom, rods as small as 0.35 mm (XUHR-M), 0.50 mm (GP-M) for the two-detector as well as the three-detector SPECT and 0.75 mm (UHS-M) were resolved. Uniformity for maximum resolution recorded 40.7% (XUHR-M), 29.1% (GP-M, U-SPECT5-E), 16.3% (GP-M, U-SPECT+) and 23.0% (UHS-M), respectively. UHS-M reached highest CNR values for low-count images; for rods smaller than 0.45 mm, acceptable CNR was only achieved by XUHR-M. GP-M was superior for imaging rods sized from 0.60-1.50 mm for intermediate activity concentrations. U-SPECT5-E and U-SPECT+ both provided comparable CNR.Conclusions: While uniformity and sensitivity are negatively affected by the absence of a third detector, the investigated U-SPECT5-E system with two stationary detectors delivers excellent spatial resolution and CNR comparable to the performance of an established three-detector-setup.

scholarly journals Development of a High-resolution SSR-SPECT System for Preclinical Imaging and Neuroimaging

2021 ◽  
Author(s):  
Annunziata D'Elia ◽  
Andrea Soluri ◽  
Filippo Galli ◽  
Sara Schiavi ◽  
Giselda De Silva ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Single Photon ◽  
Photon Emission ◽  
Small Animal Imaging ◽  
Small Animal ◽  
Emission Computed Tomography ◽  
Preclinical Research ◽  
Preclinical Imaging ◽  
Spect System

Abstract The utility of animal models in preclinical research has been increasing by the availability of methods for in vivo imaging. In particular, techniques like single photon emission computed tomography (SPECT) show high potential, which is usually limited by spatial resolution. This represents an important parameter influencing scanner design, given the small size of the anatomical structures to be investigated. The purpose of the present work was to assess the performance of a scintigraphic system with improved spatial resolution based on our previous detector by applying the Super Spatial Resolution (SSR). Our dual-head SPECT system is composed of gamma cameras based on the Hamamatsu H13700 position-sensitive photomultiplier tube (PSPMT). In each detector head, the PSPMT is coupled to a 28×28 array of CRY018 scintillation crystals. The pure Tungsten parallel square hole collimator ensures the position sensitivity, and a dedicated resistive chain readout so as an ADC board have been proprietary designed. To finalize the mechanical development of the SSR-SPECT system several tests were carried out. Based on the results obtained in the test phase, a partial review of the mechanical design was performed. Then a dedicated machine handling software was developed, and in particular, a kinematic software debugging and testing was assessed. Finally, several experiments were carried out by using Derenzo phantoms and capillaries filled with radioactive sources. Finally, the performance of our system was evaluated performing small animal imaging studies. The SPECT spatial resolution was experimentally determined to be about 1.6 mm. We reach a resolution of 1.18 mm by applying the SSR based on two images. The results of this study demonstrated the good capability of the system as a suitable tool for preclinical imaging especially in fields like neuroscience for the study of small brain structures.

scholarly journals Performance evaluation of fifth-generation ultra-high-resolution SPECT system with two stationary detectors and multi-pinhole imaging

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jan V. Hoffmann ◽  
Jan P. Janssen ◽  
Takayuki Kanno ◽  
Takayuki Shibutani ◽  
Masahisa Onoguchi ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Single Photon ◽  
Photon Emission ◽  
Small Animal ◽  
High Sensitivity ◽  
General Purpose ◽  
Emission Computed Tomography ◽  
High Count ◽  
Spect System

Abstract Background Small-animal single-photon emission computed tomography (SPECT) systems with multi-pinhole collimation and large stationary detectors have advantages compared to systems with moving small detectors. These systems benefit from less labour-intensive maintenance and quality control as fewer prone parts are moving, higher accuracy for focused scans and maintaining high resolution with increased sensitivity due to focused pinholes on the field of view. This study aims to investigate the performance of a novel ultra-high-resolution scanner with two-detector configuration (U-SPECT5-E) and to compare its image quality to a conventional micro-SPECT system with three stationary detectors (U-SPECT+). Methods The new U-SPECT5-E with two stationary detectors was used for acquiring data with 99mTc-filled point source, hot-rod and uniformity phantoms to analyse sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR). Three dedicated multi-pinhole mouse collimators with 75 pinholes each and 0.25-, 0.60- and 1.00-mm pinholes for extra ultra-high resolution (XUHR-M), general-purpose (GP-M) and ultra-high sensitivity (UHS-M) imaging were examined. For CNR analysis, four different activity ranges representing low- and high-count settings were investigated for all three collimators. The experiments for the performance assessment were repeated with the same GP-M collimator in the three-detector U-SPECT+ for comparison. Results Peak sensitivity was 237 cps/MBq (XUHR-M), 847 cps/MBq (GP-M), 2054 cps/MBq (UHS-M) for U-SPECT5-E and 1710 cps/MBq (GP-M) for U-SPECT+. In the visually analysed sections of the reconstructed mini Derenzo phantoms, rods as small as 0.35 mm (XUHR-M), 0.50 mm (GP-M) for the two-detector as well as the three-detector SPECT and 0.75 mm (UHS-M) were resolved. Uniformity for maximum resolution recorded 40.7% (XUHR-M), 29.1% (GP-M, U-SPECT5-E), 16.3% (GP-M, U-SPECT+) and 23.0% (UHS-M), respectively. UHS-M reached highest CNR values for low-count images; for rods smaller than 0.45 mm, acceptable CNR was only achieved by XUHR-M. GP-M was superior for imaging rods sized from 0.60 to 1.50 mm for intermediate activity concentrations. U-SPECT5-E and U-SPECT+ both provided comparable CNR. Conclusions While uniformity and sensitivity are negatively affected by the absence of a third detector, the investigated U-SPECT5-E system with two stationary detectors delivers excellent spatial resolution and CNR comparable to the performance of an established three-detector-setup.

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