ABSTRACT
The results obtained from the inclusion of a new intrinsic attenuation correction algorithm into a protocol for SPECT liver imaging are presented in this study. A total of six patients were evaluated with this protocol. The new algorithm uses a transmission tomographic acquisition that is obtained before a standard emission tomograph, and requires the use of an external flood source. The transmission tomograph results in an attenuation image, or map, of the patient. The attenuation map then serves as input into the final intrinsic correction algorithm, that also uses data from a standard emission acquisition. The results of the six patients studied show that the algorithm can correct for attenuation effects without degrading image quality. In all the cases studied, the attenuation corrected images made the cases easier to interpret than did the images obtained without attenuation correction.
Subject(s)
Liver Diseases/diagnostic imaging , Liver/diagnostic imaging , Tomography, Emission-Computed/methods , Aged , Humans , Image Enhancement , Male , Middle AgedABSTRACT
We discuss the basic features of a count-based algorithm for attenuation-corrected volume determination, for use with planar gamma camera images. The attenuation correction is arrived at by combining the results of two 180 degrees opposed images with a transmission image obtained with an external flood source. A sample of the imaged radioactive volume is used to convert the attenuation-corrected count to an absolute volume. The algorithm is best suited to the measurement of small to medium-sized volumes of uniform activity, such as are encountered in cardiac blood-pool imaging.
