B. Welch

University of Virginia, Charlottesville, Virginia, United States

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Publications (45)26.73 Total impact

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    ABSTRACT: Purpose: The purpose of this work is to develop an improved method for 3D molecular imaging of the breast using limited angle SPECT. Methods: The proposed method uses a variable-angle slant-hole (VASH) collimator. Rather than rotate the camera around the breast, the VASH collimator allows limited angle, tomographic acquisition while the detector remains stationary and flush against the compression paddle. This design minimizes object-to-detector distance for high spatial resolution. Theoretical analysis is presented of VASH spatial resolution and sensitivity, including depth-of-interaction (DOI) effects and magnification. The theory is compared with Monte Carlo simulation results for a point source and breast phantom including a compression paddle. An iterative reconstruction method for the slant hole data is used. Results: The theoretical model of the VASH system showed good agreement with Monte Carlo simulations based on spatial resolution, including DOI effects, and sensitivity. For 140 keV photons and a NaI(Tl) scintillator, the DOI effect resulted in roughly a 2 mm loss in spatial resolution only in depth dimension; in the other two dimensions the spatial resolution was not affected by DOI. In reconstructed breast phantom images, VASH out-performed a parallel hole SPECT approach in terms of contrast-to-noise ratio. Conclusions: The proposed method for breast imaging using limited angle SPECT and a VASH collimator demonstrated the potential for superior spatial resolution/sensitivity. In addition to high spatial resolution/sensitivity, the system design has advantages of simple detector motion, ability to image close to the chest wall and conducive to on-board biopsy and multi-modal imaging with mammography.
    IEEE Transactions on Nuclear Science 01/2014; 61(3):1143-1152. · 1.22 Impact Factor
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    ABSTRACT: The main objective of the present study was to determine if combining the two images from a conjugate counting system might improve the contrast and signal-to-noise ratio (SNR) of small lesions in all regions of the breast compared to images from a single camera. Several methods for combining the opposing pixels of the two camera images were compared: multiplication, geometric mean, and summation. The image quality metrics measured were spatial resolution, lesion contrast and lesion SNR. These quantities were evaluated both theoretically and experimentally. A capillary phantom was used to measure the spatial resolution as a function of lesion depth and to assess the translation and angular offsets between the two cameras. An acrylic box phantom, with spherical lesions suspended inside, was used to evaluate contrast and SNR as a function of lesion position. Both theoretically and experimentally the spatial resolution in the product images was superior to that in the single images, geometric mean or summation images. Relative to the single camera images, the geometric mean or the summed images, the lesion contrast and SNR of the product images were superior, irrespective of lesion depth, and were more constant with changing lesion depth compared to the single camera images. These findings suggest that improved lesion detectability is possible by imaging simultaneously from both sides of the breast, and forming a combined image using pixel-by-pixel multiplication. This may be especially important if the location of the lesion within the breast is not known a priori .
    IEEE Transactions on Nuclear Science 07/2010; · 1.22 Impact Factor
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    ABSTRACT: We have developed a novel approach that allows for fast estimation of margins of extracted lesions. Dual modality planar optical/PET scanner consists of a pair of detector heads, suitable for imaging positron-emitting radioisotopes, a mechanical fixture to maintain constant separation between the two cameras, an optical camera that provides an anatomical map, a sliding table with an attached sample holder and a common mobile gantry that supports all of the system components. The two identical detector heads are based on a 4×4 array of Hamamatsu R5900-C-8 position-sensitive photomultiplier tubes (PSPMTs) with 4 strip anodes in each orthogonal dimension. Each tube has an active region of ∼1 inch square. The PSPMT array is coupled to a matrix of LGSO scintillating crystals; with each crystal measuring 3×3×10 mm. The active area of the PET subsystem is 10 cm square. Anode readout strips are interconnected to provide 8 read-out lines for each dimension of the detector head. Detector heads are read out by a custom-built 16-channel FPGA-based ADC. Online laminography reconstruction is performed over five parallel planes, separated by a selectable distance, and images from each plane can be directly exported into an ImageJ software package for overlay and further analysis. System calibration process is described. Results of imaging of several tissue simulating materials are presented. The ability of the proposed dual-modality scanner to detect lesions in warm background has been demonstrated. Although the proposed system will not eliminate the need for pathology analysis, it will help to reduce time in surgery by unveiling insufficient margins in the sample tissue. The system will be soon demonstrated and tested in a realistic clinical environment.
    Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE; 01/2008
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    ABSTRACT: We are developing a dual modality breast scanner that can obtain x-ray transmission and gamma ray emission images in succession at multiple viewing angles with the breast held under mild compression. These views are reconstructed and fused to obtain three-dimensional images that combine structural and functional information. Here, we describe the dual modality system and present results of phantom experiments designed to test the system's ability to obtain fused volumetric dual modality data sets from a limited number of projections, acquired over a limited (less than 180 degrees) angular range. We also present initial results from phantom experiments conducted to optimize the acquisition geometry for gamma imaging. The optimization parameters include the total number of views and the angular range over which these views should be spread, while keeping the total number of detected counts fixed. We have found that in general, for a fixed number of views centered around the direction perpendicular to the direction of compression, in-plane contrast and SNR are improved as the angular range of the views is decreased. The improvement in contrast and SNR with decreasing angular range is much greater for deeper lesions and for a smaller number of views. However, the z-resolution of the lesion is significantly reduced with decreasing angular range. Finally, we present results from limited angle tomography scans using a system with dual, opposing heads.
    IEEE Transactions on Nuclear Science 07/2007; · 1.22 Impact Factor
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    ABSTRACT: Radiolabeled agents that bind to specific receptors have shown great promise in diagnosing and characterizing tumor cell biology. In vivo imaging of gene transcription and protein expression represents an other area of interest. The radioisotope I is commercially available as a label for molecular probes and utilized by researchers in small animal studies. We propose an advanced imaging detector based on planar NaI(T1) integral assembly with a Hamamatsu Flat Panel Photomultiplier (MA-PMT) representing one of the best trade-offs between spatial resolution and detection efficiency. We characterized the imaging performances of this planar detector, in comparison with a gamma camera based on a pixellated scintillator. We also tested the in-vivo image capability by acquiring images of mice as a part of a study of inflammatory bowel disease (IBD). In this study, four 25g mice with an IBD-like phenotype (SAMP1/YitFc) were injected with 375, 125, 60 and 30 muCi of I-labelled antibody against mucosal vascular addressin cell adhesion molecule (MAdCAM-1), which is up-regulated in the presence of inflammation. Two mice without bowel inflammation were injected with 150 and 60 muCi of the labeled anti-MAdCAM-1 antibody as controls. To better evaluate the performances of the integral assembly detector, we also acquired mice images with a dual modality (X and Gamma Ray) camera dedicated for small animal imaging. The results coming from this new detector are considerable: images of SAMP1/YitFc injected with 30 muCi activity show inflammation throughout the intestinal tract, with the disease very well defined at two hours post-injection.
    IEEE Transactions on Nuclear Science 07/2007; · 1.22 Impact Factor
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    ABSTRACT: Recent advances in nuclear-medicine based small-animal imaging technology have enabled researchers to acquire in vivo images of the biodistribution of radiolabeled molecules in small-animal models such as mice. The standard imaging method requires the use of anesthetic and/or physical restraint to immobilize the mouse during image acquisition of the radioisotope tracer biodistribution. This has the potential to interfere with neurological or other processes that are being studied.With this in mind, Oak Ridge National Laboratory (ORNL)and Thomas Jefferson National Accelerator Facility (Jefferson Lab), in collaboration with Royal Prince Alfred Hospital (RPAH)in Sydney, Australia and Johns Hopkins University, designed and constructed a high-resolution single-photon emission tomography (SPECT)system to study unrestrained,unanesthetized mice. Others have reported development of scintillator based PET isotope probes and systems to study the brain of unanesthetized rodents +Woody, 2001, Zimmer, 2002, Vaska, 2001-.
    05/2007: pages 239-243;
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    ABSTRACT: The goal of this study was to evaluate the efficacy of operating a two-head gamma camera system in a configuration in which the two cameras are positioned on opposite sides of the compressed breast, aligned precisely with each other and with precisely anti-parallel viewing directions. The main objective of the present study was to determine if the combination of the two resulting images might allow for better sensitivity for small lesions in all regions of the breast. Two pairs of gamma cameras were evaluated; one composed of commercially available gamma cameras and the other composed of two research-based gamma cameras. For each pair, an acrylic box phantom, with two spherical lesions suspended inside, was used to evaluate contrast and SNR as a function of lesion position, first for images from the two cameras separately and then for images obtained from pixel- by-pixel multiplication or summation of the individual images. A capillary phantom was used to quantify the spatial resolution as a function of lesion depth for the cameras individually as well as for the resulting multiplied images. Lastly, gelatin phantoms were imaged, each containing a single cube-shaped lesion of ~8 mm side length positioned at varying depths within the phantom. Relative to the single camera images or the summed images, the lesion contrast and SNR of the multiplication image were superior, irrespective of lesion depth, and were much more constant with changing lesion depth. Except when the lesion was less than a centimeter from one of the cameras, the SNR of the multiplied image exceeded that of a single camera image obtained using twice the acquisition time. These findings suggest that improved lesion detectability is possible by imaging simultaneously from both sides of the breast, especially if the location of the lesion within the breast is not known a priori.
    Nuclear Science Symposium Conference Record, 2007. NSS '07. IEEE; 01/2007
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    ABSTRACT: We report on the instrumentation development of a SPECT-CT system being configured at Johns Hopkins University to image the bio distribution of radiopharmaceuticals in unrestrained, unanesthetized mice. The gantry is a custom built X-ray computed tomography system based on the Siemens MicroCAT II imaging system. The X-ray system is composed of an 80 kVp (max), 40W X-ray source and a 2048 times 3096-pixel detector (5-frames per second readout). The mouse will be anesthetized during the X-ray CT scan. SPECT imaging will be achieved using two low profile gamma cameras, 10 cm times 20 cm in size based on a 2times4 array of Hamamatsu H8500 (8times8 anode pads) flat panel position sensitive photomultiplier tubes (PSPMT). A Nal(Tl) scintillator array with 1.2 mm pitch is mounted to the PSPMT array. The front end readout electronics combine the anode outputs of the PSPMTs of the detector head. The data acquisition system is based on two CAEN 32 channel VME peak sensing analog-digital converter (ADC) modules per detector head to digitize the outputs. An infrared based animal position tracking system will be used to monitor the mouse's head position during a SPECT scan via infrared illuminated markers attached to the mouse's head. The mouse is confined in an infrared transparent burrow at the center of rotation of the gantry. The tracking system is able to track with sub-millimeter accuracy the mouse's head position at 10-15 frames per second.
    Nuclear Science Symposium Conference Record, 2006. IEEE; 12/2006
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    ABSTRACT: A gamma-ray imaging system has been developed for acquiring stereo images of the distribution of radiopharmaceuticals in breast tissue. The system consists of a small field-of-view gamma-ray camera mounted to a stereotactic biopsy table. The camera is mounted on a rotational arm such that it can be used to image the breast from two 15deg stereo views. These stereo images can be used to determine the three dimensional spatial location of a region of focal uptake. Once the location of this region is determined, this information can be used as a guide for stereotactic core needle biopsy. The accuracy that the spatial location of a source can be determined was investigated by moving a point source within the field of view. A center-of gravity calculation was used to localize the centroid of the image of the source and this was used to determine the spatial location. Measurements indicate that the source can be localized to within 1 mm. A comparison of the operation of the gamma imaging system and an x-ray imaging system has been done using a dual modality phantom. These measurements indicated that the spatial location of an isolated source can be determined by the gamma imaging system to within approximately the same performance criteria as required for the X-ray system (1 mm). Collimators were tested to determine the spatial resolution in the transverse dimension and the impact of this transverse resolution on the axial resolution was investigated. The performance of this gamma-guided stereotactic biopsy system will be presented
    IEEE Transactions on Nuclear Science 11/2006; · 1.22 Impact Factor
  • Benjamin L Welch, Rachel Brem, Rachel Black, Stan Majewski
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    ABSTRACT: A quality assurance procedure has been developed for a prototype gamma-ray guided stereotactic biopsy system. The system consists of a compact small-field-of-view gamma-ray camera mounted to the rotational arm of a Lorad stereotactic biopsy system. The small-field-of-view gamma-ray camera has been developed for clinical applications where mammographic X-ray localization is not possible. Marker sources that can be imaged with the gamma-camera have been designed and built for quality assurance testing and to provide a fiducial reference mark. An algorithm for determining the three dimensional location of a region of interest, such as a lesion, relative to the fiducial mark has been implemented into the software control of the camera. This system can be used to determine the three-dimensional location of a region of interest from a stereo pair of images and that information can be used to guide a biopsy needle to that site. Point source phantom tests performed with the system have demonstrated that the camera can be used to localize a point of interest to within 1 mm, which is satisfactory for its use in needle localization.
    Physica Medica 02/2006; 21 Suppl 1:102-5. · 1.17 Impact Factor
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    ABSTRACT: Results of aboratory evaluations are presented of the dual-head scintimammography system using two opposed and co-registered compact gamma heads. The system is intended for clinical studies imaging suspicious lesions in a compressed breast. The studies were performed using 5 cm and 6 cm compressed breast phantoms with lesion sizes from 6 to 10 mm and lesion to breast tissue activity ratios from 6 to 10. Two imagers with a field-of-view (FOV) of 15 cm×20 cm were placed on the opposite sides of the breast phartoms. In some studies anthropomorphic torso phantom was used to simulate realistic scatter gamma radiation field. Two types of parallel-hole lead collimators were employed. Combining the co-registered images from both detector heads resulted in an over two-fold increase in lesioin contrast in the central plane of the phantom and substantially increased detection sensitivity over the whole breast volume, especially of asymmetrically placed small lesions. The results confirm the important advantage of a co-registoed two-head scintimammography system over a single head system in lesion detection and localization.
    Physica Medica 01/2006; · 1.17 Impact Factor
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    Vladimir Popov, Stan Majewski, Benjamin L. Welch
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    ABSTRACT: We have developed a new analog readout concept for multianode photomultiplier tubes with a pad matrix anode layout. This new readout technique is the result of a modification of a technique previously developed at the Detector Group of Jefferson Lab, (V. Popov, US patent No: 6,747,263 B1) [V. Popov, S. Majewski, A.G. Weisenberger, Readout Electronics for Multianode Photomultiplier Tubes with Pad Matrix Anode Layout, Thomas Jefferson National Accelerator Facility, IEEE 2003 Medical Imaging Conference Record, November 2003]. The new analog readout circuit provides the same analog conversion of matrix 2-D output into X and Y projective output with a significant reduction of analog outputs. The old readout network consists of resistors’ matrix and current collecting amplifiers, and it provides decoupling of each anode output into two directions (one to X and one to Y coordinates), but a decoupling function that is carried out independent of photomultiplier tube gains nonuniformity. A newly developed readout network (US patent pending) also consists of resistors’ matrix and current collecting amplifiers, but the new matrix includes an additional dumping resistor that provides an excess current from anode pad grounding. As a result, we subtract an extra current of high-gain pads in order to move the pads gain to an absolute minimum value for a given photomultiplier tube. This gain equalization procedure reduces image distortion related to gain nonuniformity. The new readout technique was used in several new radiation imaging detectors designed in the Detector Group of Jefferson Lab. It shows a visible readout uniformity and linearity improvement. The test results of an initial evaluation of this readout that is applied for data readout of four H8500 Hamamtsu PSPMT are presented.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2006; · 1.14 Impact Factor
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    ABSTRACT: Recently small animal research utilizing nuclear medicine based imaging has been combined with structural anatomical imaging from x-ray radiography providing a powerful tool for animal researchers. The addition of a third modality is the goal of our instrumentation development. Thomas Jefferson National Accelerator Facility and Case Western Reserve University have been collaborating on the development of a planar imaging system which in addition to radiopharmaceutical based functional imaging and x-ray radiography structural imaging also allows for the in vivo bioluminescence imaging thus providing another functional imaging modality. For the gamma camera we use is a Hamamatsu position sensitive photomultiplier tube coupled to a pixellated NaI(TI) scintillator array with individual crystal elements 1 mm × 1 mm × 5 mm in size and a 0.25 mm septum between each element. The gamma camera has a 10 cm diameter active area and can be used for <sup>125</sup>I, <sup>99m</sup>T and <sup>111</sup>In radionuclide imaging. To acquire anatomical information we are using a Rad-Icon Shad-o-Box X-ray detector that provides a field of view of 5 cm × 10 cm. The x-ray source is a Source-Ray compact x-ray generator. We are using a Princeton Instruments cooled CCD based detector for the imaging of the bio-distribution of bioluminescence. All three imaging instruments will be integrated into a single light tight / x-ray tight enclosure.
    Nuclear Science Symposium Conference Record, 2005 IEEE; 11/2005
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    ABSTRACT: A method for simultaneous geometry calibration of a dual detector SPECT system for small animal imaging is presented. For multi-headed SPECT systems, it is desirable that all detectors are calibrated with respect to a common spatial coordinate system, so that projection data from both detectors can be used to reconstruct the common object in the same image space. We adapted Beque's geometry calibration procedure. We show that the procedure can be applied to a dual-headed imaging system by optimizing the combined objective function. Initially, the measured and predicted paths of calibration point sources had significant systematic differences which were dominant in the axial direction. The problem was caused by flexing of the gantry support due to the heavy weight of the detectors. While various correction models of different complexity and assumptions could be applied, we found that the errors were corrected well by including an angle-dependent sinusoidal function to the z-coordinate, which is in the axial direction
    Nuclear Science Symposium Conference Record, 2005 IEEE; 11/2005
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    ABSTRACT: We have developed a dual-modality single photon (SPECT)/optical (OT) small animal tomographic device to image simultaneously and from identical projection angles in vivo distributions of bioluminescent/(near-infrared) fluorescent and radiolabeled markers. For the SPECT sub-system a compact gamma detector has been developed. A custom-made pinhole (PH) collimator suitable for attachment of reflective surfaces for concurrent optical imaging has been built. The collimator's reflective surfaces filter out optical photons from the multi-energetic photon flux. These photons are directed into a system of mirrors to compose an optical projection that is aligned with the angular field of view of the PH SPECT camera. For the optical detector sub-system a high resolution cooled CCD camera is used. In addition to initial small animal imaging studies several experimental phantom studies were performed with capillary tubes filled with various isotopes and optical markers to evaluate energy/wavelength/tissue dependent spatial resolution capabilities of the sub-systems.
    Nuclear Science Symposium Conference Record, 2005 IEEE; 11/2005
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    ABSTRACT: To prospectively evaluate a high-resolution breast-specific gamma camera for depicting occult breast cancer in women at high risk for breast cancer but with normal mammographic and physical examination findings. Institutional Review Board approval and informed consent were obtained. The study was HIPAA compliant. Ninety-four high-risk women (age range, 36-78 years; mean, 55 years) with normal mammographic (Breast Imaging Reporting and Data System [BI-RADS] 1 or 2) and physical examination findings were evaluated with scintimammography. After injection with 25-30 mCi (925-1110 MBq) of technetium 99m sestamibi, patients were imaged with a high-resolution small-field-of-view breast-specific gamma camera in craniocaudal and mediolateral oblique projections. Scintimammograms were prospectively classified according to focal radiotracer uptake as normal (score of 1), with no focal or diffuse uptake; benign (score of 2), with minimal patchy uptake; probably benign (score of 3), with scattered patchy uptake; probably abnormal (score of 4), with mild focal radiotracer uptake; and abnormal (score of 5), with marked focal radiotracer uptake. Mammographic breast density was categorized according to BI-RADS criteria. Patients with normal scintimammograms (scores of 1, 2, or 3) were followed up for 1 year with an annual mammogram, physical examination, and repeat scintimammography. Patients with abnormal scintimammograms (scores of 4 or 5) underwent ultrasonography (US), and those with focal hypoechoic lesions underwent biopsy. If no lesion was found during US, patients were followed up with scintimammography. Specific pathologic findings were compared with scintimammographic findings. Of 94 women, 78 (83%) had normal scintimammograms (score of 1, 2, or 3) at initial examination and 16 (17%) had abnormal scintimammograms (score of 4 or 5). Fourteen (88%) of the 16 patients had either benign findings at biopsy or no focal abnormality at US; in two (12%) patients, invasive carcinoma was diagnosed at US-guided biopsy (9 mm each at pathologic examination). High-resolution breast-specific scintimammography can depict small (<1-cm), mammographically occult, nonpalpable lesions in women at increased risk for breast cancer not otherwise identified at mammography or physical examination.
    Radiology 11/2005; 237(1):274-80. · 6.34 Impact Factor
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    ABSTRACT: We report on an approach toward the development of a high-resolution single photon emission computed tomography (SPECT) system to image the biodistribution of radiolabeled tracers such as Tc-99m and I-125 in unrestrained/unanesthetized mice. An infrared (IR)-based position tracking apparatus has been developed and integrated into a SPECT gantry. The tracking system is designed to measure the spatial position of a mouse's head at a rate of 10-15 frames per second with submillimeter accuracy. The high-resolution, gamma imaging detectors are based on pixellated NaI(Tl) crystal scintillator arrays, position-sensitive photomultiplier tubes, and novel readout circuitry requiring fewer analog-digital converter (ADC) channels while retaining high spatial resolution. Two SPECT gamma camera detector heads based upon position-sensitive photomultiplier tubes have been built and installed onto the gantry. The IR landmark-based pose measurement and tracking system is under development to provide animal position data during a SPECT scan. The animal position and orientation data acquired by the tracking system will be used for motion correction during the tomographic image reconstruction.
    IEEE Transactions on Nuclear Science 07/2005; · 1.22 Impact Factor
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    ABSTRACT: A small animal single photon emission computed tomography (SPECT) system has been developed for acquiring in vivo images of the biodistribution of radiopharmaceuticals in unrestrained, awake small animal models. This system uses two dedicated gamma-ray cameras and an infrared based animal position tracking system mounted on a rotational gantry with an infrared transparent mouse burrow in the center. The original implementation of this system had two compact gamma cameras with an active area of 5 cm×5 cm. Two new gamma camera detector heads with active areas of 10 cm×20 cm have been built, tested and installed in the SPECT gantry to replace the 5 cm×5 cm detectors. The new gamma cameras are based on pixellated NaI(Tl) crystal scintillator arrays, coupled to arrays of compact position-sensitive photomultiplier tubes (PSPMT) to achieve high spatial resolution in a compact, low profile device. A novel cost-effective readout is utilized. The two detector heads are based on a 4×8 array of Hamamatsu R8520-C12 position sensitive photomultiplier tubes. Each PSPMT array is coupled to a pixellated 10 cm×20 cm NaI(Tl) scintillator crystal array with individual crystal elements of 2 mm×2 mm×15 mm in size and a septum of 0.25 mm between elements. Samples of phantom and animal studies are presented. The detectors are capable of imaging <sup>125</sup>I and <sup>99m</sup>Tc labeled radiopharmaceuticals in live mice.
    Nuclear Science Symposium Conference Record, 2004 IEEE; 11/2004
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    ABSTRACT: An optical landmark-based pose measurement and tracking system has been developed to provide 3D animal position data for a single photon emission computed tomography (SPECT) imaging system for non-anesthetized, unrestrained laboratory animals. The animal position and orientation data provides the opportunity for motion correction of the SPECT data. The tracking system employs infrared (IR) markers placed on the animal's head along with strobed IR LEDs to illuminate the reflectors. A stereo CMOS camera system acquires images of the markers through a transparent enclosure. Software routines segment the markers, reject unwanted reflections, determine marker correspondence, and calculate the 3D pose of the animal's head. Recent improvements have been made in this tracking system including enhanced pose measurement speed and accuracy, improved animal burrow design, and more effective camera positioning for enhanced animal viewing. Furthermore, new routines have been developed to calibrate the SPECT detector head positions relative to one another and to align the coordinate systems of the optical tracking cameras with the SPECT detectors. This alignment enables motion-corrected SPECT image reconstruction. Phantom experiments validate the accuracy of the tracking system to better than 0.1 mm accuracy, and live mouse tracking results demonstrate that reliable, accurate tracking measurements can be consistently achieved during the entire 360-degree SPECT image acquisition.
    Nuclear Science Symposium Conference Record, 2004 IEEE; 11/2004
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    ABSTRACT: We are developing a dual modality breast scanner that can obtain X-ray transmission and gamma ray emission images in succession at multiple viewing angles with the breast held under mild compression. These views are then reconstructed and fused to obtain three-dimensional images that combine structural and functional information. Here we describe the dual modality system and present results of phantom experiments designed to test the system's ability to obtain volumetric dual modality data sets from a limited number of projections, acquired over a limited (less than 180 degrees) angular range.
    Nuclear Science Symposium Conference Record, 2004 IEEE; 11/2004

Publication Stats

297 Citations
26.73 Total Impact Points

Institutions

  • 2002–2010
    • University of Virginia
      • Department of Radiology and Medical Imaging
      Charlottesville, Virginia, United States
  • 2002–2007
    • Thomas Jefferson National Accelerator Facility
      • Division of Physics
      Newport News, Virginia, United States
  • 2002–2006
    • Oak Ridge National Laboratory
      Oak Ridge, Florida, United States
  • 2005
    • George Washington University
      • Department of Radiology
      Washington, D. C., DC, United States
  • 2003–2005
    • Newport Laboratories
      Worthington, Minnesota, United States
    • Hampton University
      • Department of Physics
      Hampton, VA, United States