Compton Scattering in Clinical PET/CT With High Resolution Half Ring PET Insert Device

Komarov, Sergey; Wu, Heyu; Keesing, Daniel B.; O'Sullivan, Joseph A.; Tai, Yu‐Chong

doi:10.1109/tns.2010.2046754

Cited by 15 publications

(15 citation statements)

References 6 publications

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“…One implementation of such a methodology, the Single Scatter Simulation algorithm [36] has been used for scatter correction in the PET insert device developed by the Washington University group [37].…”

Section: Object-scattered Eventsmentioning

confidence: 99%

“…The technique makes use of a clinical scanner and its only requirement is that a limited number of high-resolution detectors to be connected with a, possibly already-existing, system. This application has been proposed using the ring insert concept, employing a partial ring of highresolution scintillation detectors in coincidence with a whole-body scanner [36,37]. A prototype of the system has shown improvements in spatial resolution and contrast recovery in a cylindrical phantom [16].…”

Section: Breast Imagingmentioning

confidence: 99%

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Study of a high-resolution PET system using a Silicon detector probe

et al. 2014

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A high-resolution silicon detector probe, in coincidence with a conventional PET scanner, is expected to provide images of higher quality than those achievable using the scanner alone. Spatial resolution should improve due to the finer pixelization of the probe detector, while increased sensitivity in the probe vicinity is expected to decrease noise. A PET-probe prototype is being developed utilizing this principle. The system includes a probe consisting of ten layers of silicon detectors, each a 80 × 52 array of 1 × 1 × 1 mm 3 pixels, to be operated in coincidence with a modern clinical PET scanner. Detailed simulation studies of this system have been performed to assess the effect of the additional probe information on the quality of the reconstructed images. A grid of point sources was simulated to study the contribution of the probe to the system resolution at different locations over the field of view (FOV). A resolution phantom was used to demonstrate the effect on image resolution for two probe positions. A homogeneous source distribution with hot and cold regions was used to demonstrate that the localized improvement in resolution does not come at the expense of the overall quality of the image. Since the improvement is constrained to an area close to the probe, breast imaging is proposed as a potential application for the novel geometry. In this sense, a simplified breast phantom, adjacent to heart and torso compartments, was simulated and the effect of the probe on lesion detectability, through measurements of the local contrast recovery coefficient-to-noise ratio (CNR), was observed. The list-mode ML-EM algorithm was used for image reconstruction in all cases. As expected, the point spread function of the PETprobe system was found to be non-isotropic and vary with position, offering improvement in specific regions. Increase in resolution, of factors of up to Institute of Physics and Engineering in Medicine

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Section: Object-scattered Eventsmentioning

confidence: 99%

Section: Breast Imagingmentioning

confidence: 99%

Study of a high-resolution PET system using a Silicon detector probe

et al. 2014

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“…The estimated scattering component is scaled to fit the data at tails of the prompt minus random profile in sinogram space. The comparison of MC simulated and SSS estimate scattering component have shown that SSS is a good approximation and the multiple scattering and scattering by the insert is only a small fraction of the total scattering component [4].…”

Section: Reconstructionmentioning

confidence: 96%

“…The scattering for reconstruction is approximated using an SSS estimate [4,5,6]. SSS does not account for multiple scattering events.…”

Section: Reconstructionmentioning

confidence: 99%

Investigation of breast cancer detectability using PET insert with whole-body and zoom-in imaging capability

Mathews

Komarov

Kume

et al. 2011

2011 IEEE International Symposium on Biomedical Imaging: From Nano to Macro

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Traditional whole-body PET scanner is limited in resolution due to large detector crystal size, finite positron range and non-collinearity of annihilation photons. Our lab has developed a prototype half ring insert PET system that can improve resolution and radionuclide contrast recovery by using (1) smaller size of the detector crystals (2) virtual pinhole PET geometry obtained by placing the insert close to the imaging subject. This design allows for zooming-in to an area of interest while still maintaining the scanners whole-body imaging capability. To find the limits of the image resolution and contrast recovery, we performed a set of Monte Carlo simulations for a clinical PET system with and without half ring insert. The reconstructed images show the improvement in image resolution, with 3 mm diameter tumors resolvable with insert at a contrast ratio of 9:1, compared to scanner without insert where smallest tumors resolvable was 6 mm.

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“…In our lab we are developing a high resolution insert device to clinical PET scanner [9]. Our insert device consists of 28 high resolution detectors (13 × 13 LSO crystals of 2 × 2 × 5 mm 3 each) arranged into two half rings( R = 124mm).…”

Section: Introductionmentioning

confidence: 99%

Parallel Beam Approximation for Calculation of Detection Efficiency of Crystals in PET Detector Arrays

Komarov

Song

et al. 2011

IEEE Trans. Nucl. Sci.

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In this work we propose a parallel beam approximation for the computation of the detection efficiency of crystals in a PET detector array. In this approximation the detection efficiency of a crystal is estimated using the distance between source and the crystal and the pre-calculated detection cross section of the crystal in a crystal array which is calculated for a uniform parallel beam of gammas. The pre-calculated detection cross sections for a few representative incident angles and gamma energies can be used to create a look-up table to be used in simulation studies or practical implementation of scatter or random correction algorithms. Utilizing the symmetries of the square crystal array, the pre-calculated look-up tables can be relatively small. The detection cross sections can be measured experimentally, calculated analytically or simulated using a Monte Carlo (MC) approach. In this work we used a MC simulation that takes into account the energy windowing, Compton scattering and factors in the “block effect”. The parallel beam approximation was validated by a separate MC simulation using point sources located at different positions around a crystal array. Experimentally measured detection efficiencies were compared with Monte Carlo simulated detection efficiencies. Results suggest that the parallel beam approximation provides an efficient and accurate way to compute the crystal detection efficiency, which can be used for estimation of random and scatter coincidences for PET data corrections.

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Compton Scattering in Clinical PET/CT With High Resolution Half Ring PET Insert Device

Cited by 15 publications

References 6 publications

Study of a high-resolution PET system using a Silicon detector probe

Study of a high-resolution PET system using a Silicon detector probe

Investigation of breast cancer detectability using PET insert with whole-body and zoom-in imaging capability

Parallel Beam Approximation for Calculation of Detection Efficiency of Crystals in PET Detector Arrays

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