A nuclear radiation detector system with integrated readout for SPECT/MR small animal imaging

Azman, Suleyman; Gjaerum, J.; Meier, Dirk; Muftuler, L. Tugan; Mæhlum, G.; Nalcioğlu, Orhan; Patt, Bradley E.; Sundal, B.; Szawłowski, M.; Tsui, B.M.W.; Wagenaar, Douglas J.; Wang, Yuchuan

doi:10.1109/nssmic.2007.4436608

Cited by 11 publications

(4 citation statements)

References 8 publications

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“…Many researchers have experimented with various approaches to overcome these issues. Several studies have reported on the design considerations of an MR-compatible nuclear detector based on cadmium zinc telluride (CZT) for combined SPECT/MRI (Wagenaar et al 2006a, 2006b, Azman et al 2007, Meng et al 2007. In a simulation study, Chen et al (2007) proposed constructing SPECT detector modules assembled with a multi-pinhole cylindrical γ -ray radiation shield to be inserted into the bore of an MRI scanner to acquire SPECT/MR images.…”

Section: Introductionmentioning

confidence: 99%

Development of a new RF coil and γ-ray radiation shielding assembly for improved MR image quality in SPECT/MRI

Ha¹,

Hamamura²,

Roeck³

et al. 2010

Phys. Med. Biol.

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Magnetic resonance (MR)-based multimodality imaging systems, such as single-photon emission tomography (SPECT)/magnetic resonance imaging (MRI) or positron emission tomography (PET)/MRI, face many difficulties because of problems with the compatibility of the nuclear detector system with the MR system. However, several studies have reported on the design considerations of MR-compatible nuclear detectors for combined SPECT/MRI. In this study, we developed a new radiofrequency (RF) coil and gamma-ray radiation shielding assembly to advance the practical implementation of SPECT/MRI in providing high sensitivity while minimizing the interference between the MRI and SPECT systems. The proposed assembly consists of a three-channel receive-only RF coil and gamma-ray radiation shields made of a specialized lead composite powder designed to reduce conductivity and thus minimizing any effect on the magnetic field arising from the induced eddy currents. A conventional birdcage RF coil was also tested for comparison with the proposed RF coil. Quality (Q)-factors were measured using both RF coils without any shielding, with solid lead shielding, and with our composite lead shielding. Signal-to-noise ratios (SNRs) were calculated using 4 T MR images of phantoms both with and without the new gamma-ray radiation shields. The Q-factor and SNR measurements demonstrate the improved MRI performance due to the new RF coil/gamma-ray radiation shield assembly designed for SPECT/MRI, making it a useful addition to multimodality imaging technology not only for animal studies but also for in vivo study of humans.

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Section: Introductionmentioning

confidence: 99%

Development of a new RF coil and γ-ray radiation shielding assembly for improved MR image quality in SPECT/MRI

Ha¹,

Hamamura²,

Roeck³

et al. 2010

Phys. Med. Biol.

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“…17 A fully stationary system was also developed using CZT detector modules, for a 12-cm bore preclinical MRI system. [18][19][20] Similarly, Meng et al developed a SPECT insert for a 22-cm bore 4.7 T MRI. 21,22 More recently, the MRC-SPECT (Ref.…”

Section: Introductionmentioning

confidence: 99%

Collimator design for a multipinhole brain SPECT insert for MRI

et al. 2015

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Purpose: Brain single photon emission computed tomography (SPECT) imaging is an important clinical tool, with unique tracers for studying neurological diseases. Nowadays, most commercial SPECT systems are combined with x‐ray computed tomography (CT) in so‐called SPECT/CT systems to obtain an anatomical background for the functional information. However, while CT images have a high spatial resolution, they have a low soft‐tissue contrast, which is an important disadvantage for brain imaging. Magnetic resonance imaging (MRI), on the other hand, has a very high soft‐tissue contrast and does not involve extra ionizing radiation. Therefore, the authors designed a brain SPECT insert that can operate inside a clinical MRI. Methods: The authors designed and simulated a compact stationary multipinhole SPECT insert based on digital silicon photomultiplier detector modules, which have shown to be MR‐compatible and have an excellent intrinsic resolution (0.5 mm) when combined with a monolithic 2 mm thick LYSO crystal. First, the authors optimized the different parameters of the SPECT system to maximize sensitivity for a given target resolution of 7.2 mm in the center of the field‐of‐view, given the spatial constraints of the MR system. Second, the authors performed noiseless simulations of two multipinhole configurations to evaluate sampling and reconstructed resolution. Finally, the authors performed Monte Carlo simulations and compared the SPECT insert with a clinical system with ultrahigh‐resolution (UHR) fan beam collimators, based on contrast‐to‐noise ratio and a visual comparison of a Hoffman phantom with a 9 mm cold lesion. Results: The optimization resulted in a stationary multipinhole system with a collimator radius of 150.2 mm and a detector radius of 172.67 mm, which corresponds to four rings of 34 diSPM detector modules. This allows the authors to include eight rings of 24 pinholes, which results in a system volume sensitivity of 395 cps/MBq. Noiseless simulations show sufficient axial sampling (in a Defrise phantom) and a reconstructed resolution of 5.0 mm (in a cold‐rod phantom). The authors compared the 24‐pinhole setup with a 34‐pinhole system (with the same detector radius but a collimator radius of 156.63 mm) and found that 34 pinholes result in better uniformity but a worse reconstruction of the cold‐rod phantom. The authors also compared the 24‐pinhole system with a clinical triple‐head UHR fan beam system based on contrast‐to‐noise ratio and found that the 24‐pinhole setup performs better for the 6 mm hot and the 16 mm cold lesions and worse for the 8 and 10 mm hot lesions. Finally, the authors reconstructed noisy projection data of a Hoffman phantom with a 9 mm cold lesion and found that the lesion was slightly better visible on the multipinhole image compared to the fan beam image. Conclusions: The authors have optimized a stationary multipinhole SPECT insert for MRI and showed the feasibility of doing brain SPECT imaging inside a MRI with an image quality similar to the best clinical SPECT systems ava...

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“…F OR over a century, X-ray imaging detectors have operated in energy integrating mode [1][2][3], where images are formed by integrating the light emitted from X-ray interactions in a phosphorescent/scintillating material over a finite acquisition time, without regard to event energy or number of events, whether using film or "digital" detectors. By comparison, the next generation of X-ray detectors for CT and digital radiography will be capable of detecting and counting individual X-ray photons and recording their interaction locations and energies [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Direct and indirect detectors for X-ray photon counting systems

Prekas

Sabet

Bhandari

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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Most currently available X-ray or gamma ray imaging detectors are based on energy integration over a certain period of time. We have been developing X-ray and gamma ray detectors based on the photon counting (with energy determination) concept using both direct and indirect radiation conversion, together with associated application-specific integrated circuits (ASICs). As an alternative to our ASIC design approach, we are also exploiting the potential of state-of-the-art silicon photomultipliers (SiPMs) and discrete electronics. In this paper we discuss the advantages and disadvantages of these two approaches and we report our latest results on our ASIC design efforts and our achievements on SiPMlCsI:TI detector configurations. We will also discuss the potential uses and advantages that each offers to applications in medicine, imaging, homeland security and industry.

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A nuclear radiation detector system with integrated readout for SPECT/MR small animal imaging

Cited by 11 publications

References 8 publications

Development of a new RF coil and γ-ray radiation shielding assembly for improved MR image quality in SPECT/MRI

Development of a new RF coil and γ-ray radiation shielding assembly for improved MR image quality in SPECT/MRI

Collimator design for a multipinhole brain SPECT insert for MRI

Direct and indirect detectors for X-ray photon counting systems

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