PET attenuation correction using reprojection of measured transmission data
Meaningful quantitative positron emission tomographic (PET) measurements require accurate corrections for tissue attenuation. Although the analytic method of attenuation correction (AAC) is simple and does not contribute any statistical noise to the reconstructed emission image, it is subject to error when the object under study is of nonuniform density. Direct object/air transmission ratios obtained using an external 511 keV source are advantageous for studies which include the oral and nasal cavities or bony structures. The major problem with conventional experimental attenuation correction (CEAC) is the statistical uncertainty in the transmission measurement. A method has been developed for reducing the variance in the emission image introduced by experimental attenuation correction: transmission data are first reconstructed to form a CT image, i.e., a map of tissue attenuation for 511 keV photons, and correction coefficients are derived by reprojecting through the transmission CT image. The attenuation correction coefficients derived using this reprojected attenuation correction (RAC) are both theoretically and experimentally ''less noisy'' than those derived from CEAC. This is apparent in sinogram displays of the attenuation correction coefficients from phantom and patient studies. The effect of attenuation correction on the final, corrected emission image is dependent upon correlations in the data, the transmission properties of the object, the statistics of the emission and transmission measurements and reconstruction filter. The quantitative advantage derived from the use of RAC compared with CEA and AAC will depend upon these factors.
- Research Organization:
- Memorial Sloan-Kettering Cancer Center, New York, NY
- OSTI ID:
- 6779512
- Report Number(s):
- CONF-840619-
- Journal Information:
- J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 25:5; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ACCURACY
ANIMAL TISSUES
ATTENUATION
BODY
BODY AREAS
COMMUNICATIONS
COMPUTERIZED TOMOGRAPHY
CORRECTIONS
DATA COVARIANCES
DATA TRANSMISSION
DENSITY
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DIGITAL FILTERS
EMISSION
EMISSION COMPUTED TOMOGRAPHY
ENERGY RANGE
ERRORS
FACE
HEAD
IMAGE PROCESSING
KEV RANGE
KEV RANGE 100-1000
MATHEMATICS
NOSE
ORAL CAVITY
PHYSICAL PROPERTIES
POSITRON COMPUTED TOMOGRAPHY
PROCESSING
RESPIRATORY SYSTEM
STATISTICS
TISSUES
TOMOGRAPHY