Artificial compound-eye gamma camera for MRI compatible SPECT imaging

Lai, Xiaochun; Meng, Ling-Jian

doi:10.1109/nssmic.2013.6829175

Cited by 4 publications

(3 citation statements)

References 14 publications

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“…For rest/stress SPECT studies performed in a single imaging session, in which a pharmacologic stress is used, such registration naturally becomes much easier to perform. Also, if SPECT-CT or SPECT-MRI (Cai et al 2014, Lai and Meng 2013, 2018, Lai et al 2015 studies are used for both rest and stress studies where attenuation correction (AC) scans are available, one can use the AC images to perform image registration to reduce the likelihood of registration errors.…”

Section: Discussionmentioning

confidence: 99%

Joint reconstruction of rest/stress myocardial perfusion SPECT

et al. 2018

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Myocardial perfusion imaging (MPI) using rest/stress single photon emission computed tomography (SPECT) allows non-invasive assessment of reversible cardiac perfusion defects. Conventionally, reversible defects are identified using a difference image, called reversible map, obtained by subtracting the stress image from the rest image after registration and normalization of the two images. The identification of reversible defects using the conventional subtraction method is however limited by noise. We propose to jointly reconstruct rest and stress projection data to directly obtain the reversible map in a single reconstruction framework to improve the detectability of reversible defects. To evaluate the performance of the proposed method, we performed phantom studies to mimic reversible defects with different levels of severity and doses. As compared to the conventional subtraction method, the joint method yielded reversible maps with much lower noise and improved defect detectability. At a normal clinical dose level, the joint method improved the signal to noise ratio (SNR) of defect contrast in reversible maps from 13.2 to 66.4, 9.7 to 35.0, 6.1 to 13.2, and 3.1 to 6.5, for defect to normal myocardium concentration ratios of 0%, 25%, 50%, and 75%, respectively. The SNRs obtained using the joint method were improved from 6.1 to 13.2, 3.9 to 9.4, 3.0 to 8.0, and 2.1 to 7.1, for 100%, 75%, 50%, and 25% of the normal clinical dose as compared to the conventional subtraction method. To access clinical feasibility, we applied the joint method to a rest/stress SPECT MPI patient study. The joint method yielded a reversible map with much lower noise, translating into a much higher defect detectability as compared to the conventional subtraction method. Our results indicate that the joint method has the potential to improve radiologists' performance for assessing defects in rest/stress SPECT MPI. In addition, the joint method can be used to reduce dose or imaging time.

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Section: Discussionmentioning

confidence: 99%

Joint reconstruction of rest/stress myocardial perfusion SPECT

et al. 2018

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“…We have recently proposed an inverted-compound eye (ICE) gamma camera design (Lai et al 2013) for use with the MRC-SPECT-II system (figure 1). Each ICE camera uses a CZT or CdTe detector with a sensor area of 2.56 × 2.56 cm 2 coupled to an aperture with 8 × 8 pinholes, each with a diameter of 300-500 μm (300 μm in this study).…”

Section: Design Of the Inverted-compound-eye Gamma Camera And The Mrc...mentioning

confidence: 99%

Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

Lai

Meng

2018

Phys. Med. Biol.

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In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diameter of 6 cm. This system provides a FOV of 1 cm diameter and a peak geometrical efficiency of approximately 1.3% (the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a sub-500 μm spatial resolution. Compared to the first-generation MRC-SPECT system (MRC-SPECT-I) (Cai 2014 Nucl. Instrum. Methods Phys. Res. A 734 147-51) developed in our lab, the MRC-SPECT-II system offers a similar resolution with dramatically improved sensitivity and greatly reduced physical dimension. The latter should allow the system to be placed inside most clinical and pre-clinical MRI scanners for high-performance simultaneous MRI and SPECT imaging.

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“…Fortunately, the advent of metal additive manufacturing has opened the doors to a much wider freedom in collimator design (Deprez et al 2013a(Deprez et al , 2013b. Two important examples of this are the lofthole collimator (Deprez et al 2013), a variation on the traditional pinhole collimator that allows a higher detector coverage without multiplexing, and the artificial compound-eye (ACE) gamma camera (Lai and Meng 2013), with closely packed micro-pinhole apertures for high sensitivity, dense angular sampling, and compact SPECT imaging.…”

Section: Introductionmentioning

confidence: 99%

Parallel-hole collimator concept for stationary SPECT imaging

Pato

Vandenberghe²,

Zedda³

et al. 2015

Phys. Med. Biol.

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Parallel-hole SPECT collimators have traditionally been manufactured by stacking sheets of lead foil or by casting. These techniques significantly restrict our options in terms of collimator geometry. However, recent developments in metal additive manufacturing are making novel collimator designs possible, giving rise to new opportunities in SPECT imaging. In this paper we propose an innovative type of collimator for stationary SPECT, using parallel-holes whose collimation direction depends on their axial position. Its main advantage compared to current stationary SPECT systems (which are based on pinholes) is that, using only axial bed translations, we can achieve complete angular sampling of an increased portion of the transaxial area of the collimator bore. This allows the system to be much more compact than current stationary SPECT systems that image objects of the same size. We describe three possible designs, for full-body, brain and small-animal imaging, respectively, and test their feasibility using simulations. The system modeling method is validated against realistic Monte Carlo simulations, and then used in the evaluation of the systems' performances and reconstructions. The simulations show that the system is able to reconstruct objects occupying the predicted field of view ([Formula: see text] of the transaxial area of the bore) without sampling artifacts. In particular, we perform reconstructions from noisy projection data obtained for an activity and scanning time similar to standard protocols for the three applications, and the resulting images indicate the possibility of using the proposed systems in practice.

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Artificial compound-eye gamma camera for MRI compatible SPECT imaging

Cited by 4 publications

References 14 publications

Joint reconstruction of rest/stress myocardial perfusion SPECT

Joint reconstruction of rest/stress myocardial perfusion SPECT

Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

Parallel-hole collimator concept for stationary SPECT imaging

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