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J. N. AARSVOLD,
R. A. MINTZER,
N. J. YASILLO,
S. J. HEIMSATH,
T. A. BLOCK,
K. L. MATTHEWS,
X. PAN,
C. WU, R. N. BECK,
C-T. CHEN,
M. COOPER
Annals of the New York Academy of Sciences 12/2006; 720(1):192 - 205. · 3.15 Impact Factor
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R.N. Beck
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ABSTRACT: The rate of discovery in the natural sciences has been accelerated by powerful computer-based imaging methods, which enable scientists to map certain object properties into an `image space'. These methods also support the goals of medicine, education, art, commerce, and the media. Every digital imaging method involves a sequence of interdependent steps: namely, image-data acquisition, reconstruction and processing, recording and distribution, display/visualization, observation and analysis, and a criterion for image evaluation. When viewed within the context of imaging science, `optimal' image processing must take account of how the image-data are acquired and the intervening steps leading to how the images are to be evaluated, based on a well-defined goal and criterion
Image Processing, 1995. Proceedings., International Conference on; 11/1995
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ABSTRACT: The feasibility of employing maximum-likelihood (ML) position
estimation in small scintillation cameras for use in FDG coincidence
imaging was investigated. A small camera consisting of a Hamamatsu
R-2487 position-sensitive photomultiplier tube (PSPMT) coupled to a
single 8 mm thick NaI(Tl) crystal was calibrated with a tungsten and
lead shielded 511 keV <sup>18</sup>F source. The same calibration method
has been previously employed at 140 keV using <sup>99m</sup>Tc. The
source was positioned at each location of the image space to determine
detector-signal distributions used in look-up table (LUT) generation.
Corrected 511 keV point-array and flood images were obtained using the
resulting 511 keV calibration LUT. Resolution was 2.0 mm-2.5 mm
full-width at half maximum (FWHM). This demonstrates that it may be
feasible to use ML estimation to obtain accurate event positioning in
similar imaging detectors employing more suitable scintillators
Nuclear Science Symposium and Medical Imaging Conference Record, 1995., 1995 IEEE; 11/1995
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ABSTRACT: We have described a mobile miniature-gamma-camera system for use in electrical trauma units and have presented images and imaging characteristics of a prototype system. The system has as its principal component a miniature gamma camera based on a PSPMT. The camera is 92 mm x 92 mm x 190 mm in size, weighs 5 kg, has a 48 mm x 48 mm field of view, and has an intrinsic resolution of approximately 3 mm FWHM and 6 mm FWTM. It is expected that devices of this type will be useful as imaging tools in electrical trauma units and laboratories where imaging studies regarding uptake mechanisms of radiopharmaceuticals for assessing tissue viability are carried out.
Annals of the New York Academy of Sciences 06/1994; 720:192-205. · 3.15 Impact Factor
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N.J. Yasillo,
R.A. Mintzer,
J.N. Aarsvold,
K.L. Matthews,
S.J. Heimsath,
C.E. Ordonez,
X. Pan,
C. Wu,
T.A. Block, R.N. Beck,
C.-T. Chen,
M. Cooper
Nuclear Science Symposium and Medical Imaging Conference, 1993., 1993 IEEE Conference Record.; 12/1993
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R N Beck
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ABSTRACT: The traditional disciplines of science are grounded in the observation and measurement of object properties. Recent advances in digital computer technology have spawned numerous computer-based imaging systems that extend the range of observation and measurement into realms that would otherwise be inaccessible. More importantly, the same set of principles, concepts, strategies, and methods may be used to address the generic issues involved in the production and use of all digitized images. Recognition of this fact is giving rise to the new discipline of imaging science, with its own intellectual agenda.
Proceedings of the National Academy of Sciences 12/1993; 90(21):9746-50. · 9.68 Impact Factor
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R N Beck
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ABSTRACT: Acceleration of the emergence of imaging science as a new discipline will require the development of new organizational structures to foster research and educational programs that integrate components of the traditional disciplines, all of which stand to benefit. However, the greatest impact of imaging science will likely be from computer-based general educational programs that present both visual and verbal materials utilizing software that is not only interactive but also analytic, diagnostic, and adaptive in response to individual students. Ultimately, this powerful learning paradigm will have profound effects on all aspects of our culture. Imaging science will not have emerged fully until the conceptual, organizational, educational, cultural, and ethical issues it raises have been addressed.
Proceedings of the National Academy of Sciences 12/1993; 90(21):9803-7. · 9.68 Impact Factor
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ABSTRACT: This is a report of progress in Year Two (January 1, 1990--December 31, 1990) of Grant FG02-86ER60438, Quantitative Studies in Radiopharmaceutical Science,'' awarded for the three-year period January 1, 1989--December 31, 1991 as a competitive renewal following site visit in the fall of 1988. This program addresses the problems involving the basic science and technology underlying the physical and conceptual tools of radioactive tracer methodology as they relate to the measurement of structural and functional parameters of physiologic importance in health and disease. The principal tool is quantitative radionuclide imaging. The overall objective of this program is to further the development and transfer of radiotracer methodology from basic theory to routine clinical practice in order that individual patients and society as a whole will receive the maximum net benefit from the new knowledge gained. The focus of the research is on the development of new instruments and radiopharmaceuticals, and the evaluation of these through the phase of clinical feasibility. 25 refs., 13 figs., 1 tab.
08/1990;
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ABSTRACT: An algorithm is proposed for three-dimensional image
reconstruction in nuclear medicine which uses scattered radiation rather
than multiple projected images to determine the source depth within the
body. Images taken from numerous energy windows are combined to
construct the source distribution in the body. The gamma-ray camera is
not moved during the imaging process. Experiments with both <sup>99m
</sup>Tc and <sup>67</sup>Ga demonstrate that two channels of depth
information can be extracted from the low-energy images produced by
scattered radiation. By combining this technique with standard SPECT
(single-photon emission computed tomography) reconstruction using
multiple projections, the authors anticipate much improved spatial
resolution in the overall three-dimensional reconstruction
IEEE Transactions on Nuclear Science 07/1990; · 1.45 Impact Factor
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ABSTRACT: It is pointed out that many potentially practical applications for
nuclear medicine diagnostic procedures are difficult or impossible to
perform because of the physical size of existing mobile gamma cameras.
With the commercial availability of position sensitive photomultiplier
tubes (PSPMTs) the development of an instrument ideally suited to these
applications now appears to be practical. The major components necessary
to construct such a camera have been tested, and a circuit configuration
designed to provide a high level of clinical performance in such a
device is proposed. Spatial resolution and linearity data from a
developmental prototype are provided. Measurements have shown that by
using conventional sum and difference analog circuits only, a
76-mm<sup>2</sup> PSPMT has good linearity and therefore uniformity of
sensitivity over only the central 60% of its absolute field of view. It
is believed that this high-quality imaging area can be increased to
virtually the full field of view by implementing a digital geometric
correction scheme using a position vector lookup table
IEEE Transactions on Nuclear Science 05/1990; · 1.45 Impact Factor
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European Journal of Pharmacology 02/1990; 175(3):363-4. · 2.52 Impact Factor
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ABSTRACT: Three patients with intractable epilepsy, two with brain tumors, and one with encephalitis were imaged with magnetic resonance (MR) and positron emission tomography (PET). MR data were used to construct a three-dimensional (3D) computer model of the brain surface depicting the precentral (movement), postcentral (sensation), left inferior frontal (speech), and left superior temporal (hearing) gyri. PET-derived measurements of average surface metabolism were encoded as colors and mapped onto the 3D model by means of a retrospective technique for registering the two scans. The integrated 3D model depicted the location of PET-detected metabolic abnormalities with respect to the gyral anatomy visualized with MR. In each case, the predicted relationships were confirmed intraoperatively by means of inspection of the brain and electroencephalography. Multimodality 3D displays are likely to be particularly valuable for interpreting PET studies of epileptic patients and others with normal MR anatomy.
Radiology 10/1989; 172(3):783-9. · 5.73 Impact Factor
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ABSTRACT: This program, during the past 30 years, has developed with the constant awareness of the close interrelationships and interdependence between clinical needs, radiopharmaceutical and instrument developments, and clinical feasibility studies. This is a year of transition for this contract with two of the responsible investigators, Katherine Lathrop and Paul Harper, reaching the age of mandatory retirement. This report focuses on the completion and write-up of current research projects by Dr. Harper and Mrs. Lathrop. 4 refs.
08/1985;
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ABSTRACT: Corrections for photon attenuation in positron emission tomography (PET) will, in general, affect quantitative accuracy and noise characteristics of the reconstructed images. Each correction approach provides certain advantages as well as disadvantages. The choice of the best method for a particular study depends on the task objective, e.g., lesion detection or quantitation, and limits of acquisition and processing time. In the present study, the following attenuation correction methods have been systematically evaluated for brain imaging with PET: (1) analytical model method; (2) direct transmission measurement method; (3) smoothed transmission data method; (4) reconstructed transmission image method; (5) object contour method; and (6) boundary method. Criteria for evaluating the performance of these methods have been developed in terms of computation efficiency and image quality descriptors such as quantitative accuracy, reconstructed image resolution, and noise characteristics. Effects of total number of transmission counts, total number of emission counts, size of the region of interest, smoothing parameters, reconstruction filters, and object contrast have also been investigated. Based on the results of computer simulation studies, the establishment of a methodology for choosing the best attenuation correction method for a defined purpose, e.g., detecting a 2 cm diameter lesion or quantitating a 4 cm diameter region, has been attempted. This systematic approach has been applied to phantom and in vivo studies. In most cases, the smoothed transmission data method appears to be the best compromise of computation time and image quality.
12/1983
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ABSTRACT: An array of five Si(Li) detectors which partially surrounds a collimated 10 Ci 241Am source, combined with a microprocessor-controlled scanning bed, has been developed for imaging of stable iodine within the thyroid. The sensitivity of the system is sufficient to generate high-quality scan images in a scanning time of approximately 15 minutes, with a spatial resolution of 5.9 mm (FWHM). We have evaluated several phantom studies and used the results to develop a computer code which determines the total thyroid iodine content and thyroid area with acceptable accuracy.
IEEE Transactions on Nuclear Science 03/1981; · 1.45 Impact Factor
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ABSTRACT: A high-efficiency detector system developed especially for medical imaging has three speciall cut Ge(Li) coaxial detectors (total volume 249 cm3). At 122 keV, the peak efficiency is 93% of that of a 7.6 Ã 7.6 cm NaI (T1) detector. Degradation of the paralleled energy resolution is avoided and resolution is improved by 35% over that of conventional output-summing techniques by gating the detector outputs. In effect this multiplexes them to a single line output.
IEEE Transactions on Nuclear Science 03/1976; · 1.45 Impact Factor
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ABSTRACT: The feasibility of constructing a radioisotope scanner using a Ge(Li)
detector with adequate efficiency for clinical use is discussed. (WHK)
12/1974
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P V Harper,
J Schwartz, R N Beck,
K A Lathrop,
N Lembares,
H Krizek,
I Gloria,
R Dinwoodie,
A McLaughlin,
V J Stark,
C Bekerman,
P B Hoffer,
A Gottschalk,
L Resnekov,
J al-Sadir,
A Mayorga,
H L Brooks
Radiology 10/1973; 108(3):613-7. · 5.73 Impact Factor
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Journal of Nuclear Medicine 04/1973; 14(3):172-4. · 6.38 Impact Factor
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ABSTRACT: From semiconductor detectors in medicine meeting; San Francisco,
California, USA (8 Mar 1973). Some conclusions based on work toward the goal of
making the fullest use of all of the radiation detected during nuclear medicine
imaging procedures in order to minimize the radiation dose to the patient while
maximizing the diagnostic image quality are summarized. A series of studies were
done to determine the effects of scattered radiation on the sensitivity and
spatial resolution of imaging systems. The following are discussed: the theory
of optimum-weighted multichannel imaging, detection of arbitrary object
structures, and detection of sinusoidal structures. (MHR)
12/1972
