Digital Time Alignment of High Resolution PET Inveon Block Detectors

Lenox, M.; Atkins, B.; Pressley, Danny; McFarland, Aaron; Newport, D.F.; Siegel, Stefan

doi:10.1109/nssmic.2006.354407

Cited by 14 publications

(10 citation statements)

References 7 publications

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“…Unfortunately, the coincidence time resolution is usually not reported in the performance evaluations of small-animals PET scanners, impeding a comparison of our results to other scanners. Ko et al (2015) report a coincidence time resolution of 1.33 ns, and the Inveon PET has a reported time resolution of 1.22 ns (Lenox et al 2006). Our twice as good coincidence time resolution allows the use of a small coincidence time window of only 2 ns, which leads to the measured small random rates at high activities.…”

Section: Discussionmentioning

confidence: 99%

PET performance evaluation of the small-animal Hyperion II ^D PET/MRI insert based on the NEMA NU-4 standard

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Schug

Weissler

et al. 2018

Biomed. Phys. Eng. Express

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The Hyperion IID PET insert is the first scanner using fully digital silicon photomultipliers for simultaneous PET/MR imaging of small animals up to rabbit size. In this work, we evaluate the PET performance based on the National Eletrical Manufacturers Association (NEMA) NU 4-2008 standard, whose standardized measurement protocols allow comparison of different small-animal PET scanners. The Hyperion IID small-animal PET/MR insert comprises three rings of 20 detector stacks with pixelated scintillator arrays with a crystal pitch of 1 mm, read out with digital silicon photomultipliers. The scanner has a large ring diameter of 209.6 mm and an axial field of view of 96.7 mm. We evaluated the spatial resolution, energy resolution, time resolution and sensitivity by scanning a 22Na point source. The count rates and scatter fractions were measured for a wide range of 18F activity inside a mouse-sized scatter phantom. We evaluated the image quality using the mouse-sized image quality phantom specified in the NEMA NU4 standard, filled with 18F. Additionally, we verified the in-vivo imaging capabilities by performing a simultaneous PET/MRI scan of a mouse injected with 18F-FDG. We processed all measurement data with an energy window of 250 keV to 625 keV and a coincidence time window of 2 ns. The filtered-backprojection reconstruction of the point source has a full width at half maximum (FWHM) of 1.7 mm near the isocenter and degrades to 2.5 mm at a radial distance of 50 mm. The scanner’s average energy resolution is 12.7% (ΔE/E FWHM) and the coincidence resolution time is 609 ps. The peak absolute sensitivity is 4.0% and the true and noise-equivalent count rates reach their peak at an activity of 46 MBq with 483 kcps and 407 kcps, respectively, with a scatter fraction of 13%. The iterative reconstruction of the image quality phantom has a uniformity of 3.7%, and recovery coefficients from 0.29, 0.91 and 0.94 for rod diameters of 1 mm, 3 mm and 5 mm, respectively. After application of scatter and attenuation corrections, the air- and water-filled cold regions have spill-over ratios of 6.3% and 5.4%, respectively. The Hyperion IID PET/MR insert provides state-of-the-art PET performance while enabling simultaneous PET/MRI acquisition of small animals up to rabbit size.

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Section: Discussionmentioning

confidence: 99%

PET performance evaluation of the small-animal Hyperion II ^D PET/MRI insert based on the NEMA NU-4 standard

Hallen

Schug

Weissler

et al. 2018

Biomed. Phys. Eng. Express

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“…Timing alignment methods have been reported by several groups to improve timing resolution in detectors (Lenox et al , 2007) or systems (Lenox et al , 2006; Moses and Thompson, 2006). Because of the large timing shift in the PSAPD and potential integration with a MR system, these methods cannot be directly implemented in a PSAPD-based system.…”

Section: Discussionmentioning

confidence: 99%

A study of the timing properties of position-sensitive avalanche photodiodes

Yang

et al. 2009

Phys. Med. Biol.

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In this paper we study position-dependent timing shifts and timing resolution in position sensitive avalanche photodiodes (PSAPDs) and their effect on the coincidence window used in positron emission tomography (PET) systems using these devices. There is a delay in PSAPD signals that increases as the excitation position moves from the corner to the center of the device and the timing resolution concurrently worsens. The difference in timing between the center and corner can be up to 30.7 ns for a 14×14 mm2 area PSAPD. This means that a PSAPD-based PET system could require a very wide coincidence timing window (>60 ns) if this effect is not corrected, although the individual crystal pairs still have full-width half-maximum (FWHM) timing resolutions better than 7.4 ns. In addition to characterizing the timing properties of PSAPDs, two correction methods were developed and applied to data from a pair of PSAPD detectors. These two timing offset corrections reduced the timing shift of a crystal pair from 52.4 ns to 9.7 ns or 1.3 ns, improved FWHM timing resolution of the detector pair from 24.6 ns to 9.5 ns or 6.0 ns and reduced the timing window (sufficient to cover at least twice the FWHM for all crystal pairs) from 65.1 ns to 22.0 ns or 15.2 ns respectively. A two-step timing alignment method is proposed for a PET system consisting of multiple PSAPDs. Lastly, the effect of PSAPD size on the timing performance was also evaluated.

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“…5(a). The system time resolution of lnveon PET is 1.7-1.8 ns (FWHM) without any time corrections [7). The time difference histogram of coincidence only from the two WU PET insert detectors (left side in Fig.…”

Section: Ill System Testingmentioning

confidence: 99%

Extending QuickSilver™ electronics for PET insert integration

Siegel

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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The unique, circular topology of the QuickSilver electronics of the Siemens Inveon PET scanner distributes the coincidence event matching, as opposed to the traditional star structure with a centralized coincidence processor. This architecture provides a means to extend or integrate QuickSilver based systems without hardware modification. This paper reports on integrating a small, high-resolution PET insert, developed at Washington University (WU) in St. Louis, into a Siemens Inveon PET. The detectors in WU PET insert are equipped with LSO arrays coupled to Multi-Pixel Photon Counters (MPPC). Scintillation events detected by PET insert detectors are processed by a set of independent QuickSilver electronics. By placing this insert within the Inveon PET, one can achieve sub-millimeter resolution. By rerouting RocketiO (RIO, Xilinx standard) cables and modifying Field Programmable Gate Array (FPGA) firmware, the two PET systems can be integrated in such a manner as to create coincident pairs within the insert ring, within the original Inveon ring, and between the two rings.

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Digital Time Alignment of High Resolution PET Inveon Block Detectors

Cited by 14 publications

References 7 publications

PET performance evaluation of the small-animal Hyperion II ^D PET/MRI insert based on the NEMA NU-4 standard

PET performance evaluation of the small-animal Hyperion II ^D PET/MRI insert based on the NEMA NU-4 standard

A study of the timing properties of position-sensitive avalanche photodiodes

Extending QuickSilver™ electronics for PET insert integration

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Digital Time Alignment of High Resolution PET Inveon Block Detectors

Cited by 14 publications

References 7 publications

PET performance evaluation of the small-animal Hyperion II D PET/MRI insert based on the NEMA NU-4 standard

PET performance evaluation of the small-animal Hyperion II D PET/MRI insert based on the NEMA NU-4 standard

A study of the timing properties of position-sensitive avalanche photodiodes

Extending QuickSilver&#x2122; electronics for PET insert integration

Contact Info

Product

Resources

About

PET performance evaluation of the small-animal Hyperion II ^D PET/MRI insert based on the NEMA NU-4 standard

PET performance evaluation of the small-animal Hyperion II ^D PET/MRI insert based on the NEMA NU-4 standard

Extending QuickSilver™ electronics for PET insert integration