Investigation of the Use of X-ray CT Images For Attenuation Compensation in SPECT

K. J. LaCroix; B. M.W. Tsui; B. H. Hasegawa; J. K. Brown

doi:10.1109/23.340649

Investigation of the Use of X-ray CT Images For Attenuation Compensation in SPECT

K. J. LaCroix, B. M.W. Tsui, B. H. Hasegawa, J. K. Brown

Research output: Contribution to journal › Article › peer-review

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Abstract

This study investigates the general use of single-beam xray 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 (radionuclide) and polyenergetic (X-ray) 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 of201Tl and99mTc, 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.

Original language	English (US)
Pages (from-to)	2793-2799
Number of pages	7
Journal	IEEE Transactions on Nuclear Science
Volume	41
Issue number	6
DOIs	https://doi.org/10.1109/23.340649
State	Published - Dec 1994
Externally published	Yes

ASJC Scopus subject areas

Nuclear and High Energy Physics
Nuclear Energy and Engineering
Electrical and Electronic Engineering

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10.1109/23.340649

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@article{0910f2432c344259b629292a04919918,

title = "Investigation of the Use of X-ray CT Images For Attenuation Compensation in SPECT",

abstract = "This study investigates the general use of single-beam xray 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 (radionuclide) and polyenergetic (X-ray) 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 of201Tl and99mTc, 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.",

author = "LaCroix, {K. J.} and Tsui, {B. M.W.} and Hasegawa, {B. H.} and Brown, {J. K.}",

note = "Funding Information: Alternatively, attenuation maps have been generated from polyenergetic, X-ray CT images using either the conventional, single-beam X-ray CT technique [5] or using a dual-energy X-ray CT technique [6]. The conventional, single-beam X-ray CT technique is relatively inexpensive and fast, but has the disadvantage that, unlike the radionuclide TCT technique, the emission and transmission projection data are collected using different types of detectors, located on different machines. Collection of data on different machines requires image registration. Using the t This work was supported by Public Health Grant #CA50539 and by American Heart Association Grant-In-Aid #93010800. Its contents are solely the responsibility of the author and do not necessarily represent the official views of the Public Health Service.",

year = "1994",

month = dec,

doi = "10.1109/23.340649",

language = "English (US)",

volume = "41",

pages = "2793--2799",

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AU - LaCroix, K. J.

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AU - Hasegawa, B. H.

AU - Brown, J. K.

N1 - Funding Information: Alternatively, attenuation maps have been generated from polyenergetic, X-ray CT images using either the conventional, single-beam X-ray CT technique [5] or using a dual-energy X-ray CT technique [6]. The conventional, single-beam X-ray CT technique is relatively inexpensive and fast, but has the disadvantage that, unlike the radionuclide TCT technique, the emission and transmission projection data are collected using different types of detectors, located on different machines. Collection of data on different machines requires image registration. Using the t This work was supported by Public Health Grant #CA50539 and by American Heart Association Grant-In-Aid #93010800. Its contents are solely the responsibility of the author and do not necessarily represent the official views of the Public Health Service.

PY - 1994/12

Y1 - 1994/12

N2 - This study investigates the general use of single-beam xray 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 (radionuclide) and polyenergetic (X-ray) 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 of201Tl and99mTc, 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.

AB - This study investigates the general use of single-beam xray 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 (radionuclide) and polyenergetic (X-ray) 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 of201Tl and99mTc, 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.

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Investigation of the Use of X-ray CT Images For Attenuation Compensation in SPECT

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