Conference Paper

Can large-area avalanche photodiodes be used for a clinical PET/MRI block detector?

Department of Radiology and Molecular Imaging Program, Stanford, University, CA, USA
DOI: 10.1109/NSSMIC.2008.4774466 In proceeding of: Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE
Source: IEEE Xplore

ABSTRACT We are investigating a high resolution, Angerlogic based PET block detector using large-area avalanche photodiodes (LAAPD). Such block detectors will be used in a simultaneous PET/MRI clinical scanner. Using a Monte-Carlo simulation tool, we systemically optimized the detector design taking into account the following factors: the dimensions of the scintillation crystal and the optical diffuser, the surface finish of crystals, the layout of APD arrays, and the signal-to-noise (SNR) of the system. Based on the simulation results, a block detector prototype was built with an 8×8 LYSO crystal array (crystal pitch size: 2.75 × 3.00 × 20 mm3) coupled to four APDs. The performance of the block detector with regard to the crystal resolving ability and the energy resolution is reported.

0 Bookmarks
 · 
115 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PET combined with CT has proven to be a valuable multimodality imaging device revealing both functional and anatomic information. Although PET/CT has become completely integrated into routine clinical application and also has been used in small-animal imaging, CT provides only limited soft-tissue contrast and, in preclinical studies, exposes the animal to a relatively high radiation dose. Unlike CT, MRI provides good soft-tissue contrast even without application of contrast agents and, furthermore, does not require ionizing radiation. This project focused on combining a high-resolution PET scanner with a 7-T MRI system for animal research. Because classic PET detectors based on photomultiplier tubes cannot be used in high magnetic fields, we used a detector technology based on 10 x 10 lutetium oxyorthosilicate crystal arrays and 3 x 3 avalanche photodiode arrays. A ring of such PET detectors will ultimately be used as an insert for the 119-mm-diameter MRI bore. Initial measurements with 1 PET detector module in the 7-T field during application of MRI sequences were encouraging. Position profiles from the PET detectors and a first MR image of a mouse could be acquired simultaneously. Further work will concentrate on the construction of a full PET detector ring with compact, integrated electronics.
    Journal of Nuclear Medicine 05/2006; 47(4):639-47. · 5.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The relative response to X-rays and light, linearity for X-rays, and the energy resolution for both X-rays and light signal from a light emitting diode (LED) light pulser were measured for 5 mm, 10 mm and 16 mm diameter large area avalanche photodiodes (LAAPDs). It has been shown that the ratio of the LAAPD gain for 5.9 keV and 16.6 keV X-rays and the gain for a light pulse from the LED light pulser was constant (within 1-2%) up to a device (optical) gain of 100. That allows one to use the X-ray peaks as a good reference for measuring the e-h pair number of detected light pulses, particularly from scintillators. Good linearity of the LAAPDs response to X-rays was observed up to energy of about 20 keV. The energy resolutions for light signals and X-rays were compared and discussed in the light of the statistical limitation of the resolution. The comparison showed an excellent agreement for the light signal. For the X-rays, the energy resolution was affected by the non-uniformity of the gain in the active area of the photodiode, particularly observed for X-rays above 6 keV. Finally, the energy spectrum for 662 keV γ-rays from a <sup>137</sup>Cs source detected with a YAP crystal coupled to a 16 mm LAAPD was obtained, showing an excellent energy resolution of 4.30±0.15%
    IEEE Transactions on Nuclear Science 09/2000; · 1.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a discussion of a new multicrystal detector system as it is implemented in Positron Emission Tomography. The system consists of a 32 × 8 matrix of BGO crystals, a tuned light pipe, and four photomultipliers. The electronics that decodes the position consists of fast preamps, gated integrators, and level comparators. This detector represents a major development toward reducing the cost of PET.
    IEEE Transactions on Nuclear Science 03/1986; · 1.22 Impact Factor

Full-text (2 Sources)

View
25 Downloads
Available from
May 27, 2014