Abstract
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Objectives We performed an initial evaluation of a new planar imaging protocol which is applicable to most planar techniques such as bone scans, myocardial perfusion planar imaging, lymphoscintigraphy, gastric emptying etc.
Methods We modeled a planar imaging protocol in which the gamma camera would be positioned sequentially at two locations, six degrees apart, instead of in a single position. The imaging time for each of the two stereo positions would be halved, resulting in the same total acquisition time for both protocols. The stereoscopic monitor provides a 3D view of the imaged object. Computer simulations were used to create two noiseless projections corresponding to a planar bone scan. A computer program was written to display both the stereo and standard views side-by-side, and to provide the capability of changing the total number of counts from 1.5·106 to 4·106. Four viewers were asked to match noise levels in 48 image pairs for various display parameter settings and for a wide range of initial noise levels.
Results All users were easily able to visualize the bone images in three dimensions, and could clearly distinguish between image regions located at different depths. We found that the perceived image noise with stereoscopic viewing corresponds to noise levels of regular scans with 60±80% more counts due to binocular summation. This noise reduction was highly dependent on the gray-scale settings and the initial noise level, and varied slightly between viewers.
Conclusions Stereoscopic acquisition provides an alternative to standard planar protocols used in emission imaging. Three-dimensional perception of the object is easily achievable at the noise levels investigated. Binocular summation was shown to decrease perceived noise levels.
Research Support This work was supported in part by the National Cancer Institute, National Institutes of Health under Grant R21 CA123057 and American Heart Association, Scientist Development Grant, Grant 0735328N.
- © 2009 by Society of Nuclear Medicine