Investigation of the use of X-ray CT images for attenuation compensation in SPECT

Conference · Thu Dec 01 00:00:00 EST 1994 · IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:6940084

LaCroix, K J; Tsui, B M.W. ^[1]; Hasegawa, B H; Brown, J K ^[2]

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1. Univ. of North Carolina, Chapel Hill, NC (United States)
2. Univ. of California, San Francisco, CA (United States)

This study investigates the general use of single-beam X-ray computed tomography (CT) images for generating attenuation maps for compensation of photon attenuation in SPECT images. A 3D mathematical thorax phantom is used to simulate both emission and transmission projection data for monoenergetic and polyenergetic sources. Polyenergetic transmission projection data are simulated for a standard X-ray spectrum and fan-beam geometry. The projection data are reconstructed using filtered backprojection to form an X-ray CT image which is then scaled to produce an estimate of the attenuation map at the energy of the emission radionuclide. Emission projection data are simulated for a fan-beam geometry at the energies of [sup 201]Tl and [sup 99m]Tc, two radionuclides commonly used in cardiac SPECT. Detector response and scatter are not included in the model. Noiseless, emission projection data are iteratively reconstructed using the ML-EM algorithm with nonuniform attenuation compensation and attenuation maps derived from both the simulated X-ray CT image and from a simulated monoenergetic transmission CT image. The attenuation maps generated from the X-ray CT images accurately estimate the attenuation coefficient for muscle and lung tissues, but not for bone tissues, which show error in the attenuation coefficient of 21--42% for spinal bone and 34--58% for rib bone. However, despite the inaccurate estimate of bone attenuation, the reconstructed SPECT images provide estimates of myocardial radioactivity concentration to within 9% and show few artifacts.

• OSTI ID: 6940084
• Report Number(s): CONF-931051-; CODEN: IETNAE
• Journal Information: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States), Vol. 41:6Pt2; Conference: NSS-MIC '93: nuclear science symposium and medical imaging conference, San Francisco, CA (United States), 30 Oct - 6 Nov 1993; ISSN 0018-9499
• Country of Publication: United States
• Language: English

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