Calibrations and corrections of a modular cylindrical SPECT system (McSPECT-II)

Jin, Yongjie; Liu, Jingai; Chang, Wei; Liu, Yinong; Huang, Gang

doi:10.1109/23.489427

Cited by 5 publications

(1 citation statement)

References 4 publications

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“…To improve sensitivity or resolution in brain SPECT imaging, dedicated collimators and systems have been simulated and developed in the past (Habte et al 2001, Holman et al 1990, Jin et al 1995, Mahmood et al 2009, Zito et al 1993. Cone-beam collimators are a good choice because of their high sensitivity (Jaszczak et al 2006, Kamphuis and Beekman 1998, Li et al 1996, Park et al 2005, Stone et al 1998, Ter-Antonyan et al 2007, while multipinhole collimators are the best choice for high-resolution systems (Goorden et al 2009, Klein et al 1996, Rogulski et al 1993, Rowe et al 1993.…”

Section: Introductionmentioning

confidence: 99%

Design and simulation of a full-ring multi-lofthole collimator for brain SPECT

et al. 2013

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Currently, clinical brain single photon emission computed tomography (SPECT) is mostly performed using rotating dual-head gamma cameras equipped with low-energy-high-resolution parallel-beam collimators (LEHR PAR). The resolution of these systems is rather poor (8-10 mm) and the rotation of the heavy gamma cameras can introduce misalignment errors. Therefore, we designed a static full-ring multi-lofthole brain SPECT insert for an existing ring of LaBr3 (5% Ce) detectors. The novelty of the design is found in the shutter mechanism that makes the system very flexible and eliminates the need for rotating parts. A stationary SPECT insert is not only more robust, it is also easier to integrate in a magnetic resonance imaging system (MRI) for simultaneous SPECT-MRI. The target spatial resolution of our design is 6 mm. In this study we used analytical calculations to optimize the collimator for an existing ring of LaBr3 (5% Ce) detectors. We fixed the target spatial resolution at 6 mm in the center of the field-of-view and maximized the volume sensitivity by changing the collimator radius, the aperture and the number of loftholes. Based on these optimal parameters we simulated phantom data and evaluated the image quality of our multi-lofthole system. We simulated a noiseless uniform and Defrise phantom to assess artifacts and sampling completeness and a noiseless hot-rod phantom to assess the reconstructed spatial resolution. We visually evaluated a simulated noisy Hoffman phantom with two lesions. Then, we evaluated the non-prewhitening matched filter signal-to-noise ratio (NPW-SNR) in two lesion detectability phantoms: one with hot lesions and one with cold lesions. Finally, a contrast-to-noise (CNR) study was performed on a phantom with both hot and cold lesions of different sizes (6-16 mm). All results were compared to a LEHR PAR system. The optimization resulted in a final collimator design with a volume sensitivity of 1.55 × 10(-4) cps Bq(-1), which is 2.5 times lower than the sensitivity of a dual-head system with LEHR PAR collimators. Spatial resolution, on the other hand, has clearly improved compared to LEHR PAR: with the multi-lofthole system we successfully reconstructed 4 mm hot rods. Although this improved resolution did not result in an unambiguous improvement in CNR or NPW-SNR, we believe that the flexibility of the shutter mechanism opens interesting perspectives toward time-multiplexing and integration with MRI.

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Section: Introductionmentioning

confidence: 99%

Design and simulation of a full-ring multi-lofthole collimator for brain SPECT

et al. 2013

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Improving the count rate performance of a modular cylindrical SPECT system

Hollinger²,

Liu³

et al.

1996 IEEE Nuclear Science Symposium. Conference Record

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New daily detector uniformity quality control methodology for cardiac SPECT using solid-state detectors

Bai

Conwell

2010

IEEE Nuclear Science Symposuim &Amp; Medical Imaging Conference

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Detector non-uniformity can potentially introduce detectable artifacts into SPECT images. The degree of nonuniformity and the position of the non-uniform area on the detector surface determine the position and severity of the introduced artifacts. The commonly used daily uniformity quality control (QC) procedure follows the NEMA methodology but acquires fewer counts than the latter specifies. It has three major drawbacks: (1) it does not report the locations and extension of the non-uniform areas on the detector surface; (2) it may report a non-uniformity value that is lower than the true value due to the use of a 9-point filter, and it makes the reported non-uniformity value vary with the extension of the nonuniform area. These two drawbacks are inherited from the NEMA methodology. The third drawback is that the noise due to the relatively low counts collected in daily uniformity QC does not allow the measurement of certain degrees of nonuniformity with adequate statistical significance, yet such nonuniformity can potentially introduce observable artifacts. In this work we propose a new methodology for daily uniformity QC for cardiac SPECT imaging using solid-state detectors. The new QC largely overcomes the above drawbacks of NEMA QC. In addition, the new procedure (1) can catch some detectors that pass the NEMA-based daily uniformity QC but can be nonuniform enough to introduce detectable artifacts and (2) reports the locations and extension of the non-uniform areas of the detectors, therefore, may allow a detector that fails the NEMAbased daily QC to be used for imaging without introducing artifacts in certain situations.

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Calibrations and corrections of a modular cylindrical SPECT system (McSPECT-II)

Cited by 5 publications

References 4 publications

Design and simulation of a full-ring multi-lofthole collimator for brain SPECT

Design and simulation of a full-ring multi-lofthole collimator for brain SPECT

Improving the count rate performance of a modular cylindrical SPECT system

New daily detector uniformity quality control methodology for cardiac SPECT using solid-state detectors

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