TY - JOUR
T1 - Performance evaluation of A-SPECT
T2 - A high resolution desktop pinhole SPECT system for imaging small animals
AU - McElroy, David P.
AU - MacDonald, Lawrence R.
AU - Beekman, Freek J.
AU - Wang, Yuchuan
AU - Patt, Bradley E.
AU - Iwanczyk, Jan S.
AU - Tsui, Benjamin M.W.
AU - Hoffman, Edward J.
N1 - Funding Information:
Manuscript received March 19, 2002; revised Jufly 6, 2002. This work was supported by DoE Contracts DE-FC03-87ER60615, NIH 1R43MH6170, and DoE DE-FG03-99ER82854. D. P. McElroy and E. J. Hoffman are with the Division of Nuclear Medicine and Biophysics, University of California Los Angeles School of Medicine, Los Angeles CA 90095 (e-mail: dmcelroy@mednet.ucla.edu). L. R. MacDonald, B. E. Patt, and J. S. Iwanczyk are with Gamma Medica, Division of Photon Imaging, Inc., Northridge, CA 91324 USA. F. J. Beekman is with the Department of Nuclear Medicine, University Hospital Utrecht, 3584 CX, Utrecht, The Netherlands. Y. Wang and B. M. W. Tsui are with the Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 USA. Digital Object Identifier 10.1109/TNS.2002.803801
PY - 2002/10
Y1 - 2002/10
N2 - Pinhole collimation of gamma rays to image distributions of radiolabeled tracers is considered promising for use in small animal imaging. The recent availability of transgenic mice, coupled with the development of 125I and 99mTc labeled tracers, has allowed the study of a range of human disease models while creating demand for ultrahigh resolution imaging devices. We have developed a compact gamma camera that, in combination with pinhole collimation, allows for accessible, ultrahigh resolution in vivo single photon emission computed tomography (SPECT) imaging of small animals. The system is based on a pixilated array of NaI(Tl) crystals coupled to an array of position sensitive photomultiplier tubes (PSPMTs). Interchangeable tungsten pinholes with diameters ranging from 0.5 to 3 mm are available, allowing the camera to be optimized for a variety of imaging situations. We use a three dimensional maximum likelihood expectation maximization (MLEM) algorithm to reconstruct the images. Our evaluation indicates that high quality, submillimeter spatial resolution images can be achieved in living mice. Reconstructed axial spatial resolution was measured to be 0.53, 0.74, and 0.96 mm full width at half maximum (FWHM) for rotation radii of 1, 2, and 3 cm, respectively, using the 0.5-mm pinhole. In this configuration, sensitivity is comparable to that of a high-resolution parallel hole collimator. SPECT images of hot- and cold-rod phantoms and a highly structured monkey brain phantom illustrate that high quality images can be obtained with the system. Images of living mice demonstrate the ability of the system to obtain high-resolution image in vivo. The effect of object size on the quantitative assessment of isotope distributions in an image was also studied.
AB - Pinhole collimation of gamma rays to image distributions of radiolabeled tracers is considered promising for use in small animal imaging. The recent availability of transgenic mice, coupled with the development of 125I and 99mTc labeled tracers, has allowed the study of a range of human disease models while creating demand for ultrahigh resolution imaging devices. We have developed a compact gamma camera that, in combination with pinhole collimation, allows for accessible, ultrahigh resolution in vivo single photon emission computed tomography (SPECT) imaging of small animals. The system is based on a pixilated array of NaI(Tl) crystals coupled to an array of position sensitive photomultiplier tubes (PSPMTs). Interchangeable tungsten pinholes with diameters ranging from 0.5 to 3 mm are available, allowing the camera to be optimized for a variety of imaging situations. We use a three dimensional maximum likelihood expectation maximization (MLEM) algorithm to reconstruct the images. Our evaluation indicates that high quality, submillimeter spatial resolution images can be achieved in living mice. Reconstructed axial spatial resolution was measured to be 0.53, 0.74, and 0.96 mm full width at half maximum (FWHM) for rotation radii of 1, 2, and 3 cm, respectively, using the 0.5-mm pinhole. In this configuration, sensitivity is comparable to that of a high-resolution parallel hole collimator. SPECT images of hot- and cold-rod phantoms and a highly structured monkey brain phantom illustrate that high quality images can be obtained with the system. Images of living mice demonstrate the ability of the system to obtain high-resolution image in vivo. The effect of object size on the quantitative assessment of isotope distributions in an image was also studied.
KW - Animal imaging
KW - Pin hole collimation
KW - Single photon emission computed tomography (SPECT)
KW - Three-dimensional (3-D) image reconstruction
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U2 - 10.1109/TNS.2002.803801
DO - 10.1109/TNS.2002.803801
M3 - Article
AN - SCOPUS:0036815779
VL - 49 I
SP - 2139
EP - 2147
JO - IEEE Transactions on Nuclear Science
JF - IEEE Transactions on Nuclear Science
SN - 0018-9499
IS - 5
ER -