title: Quantitative imaging using the Cleon emission tomography system: recent developments.
abstract: A revised method of correcting for attenuation has been investigated through experiments using discrete sources within a radioactive background. The effects of changing the source size, the source position relative to the central axis, and the ratio of the concentrations in the source and background have been studied. A comparison of the results obtained using old and new attenuation corrections show marked improvement. The measurement of radioactive concentration on the central axis had a typical systematic error of -14%, compared to -60% previously, but is generally dependent on source size, source position, and source and background concentrations. An allowance can be made for this error using experimental data.
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging; D006801:Humans; D008961:Models, Structural; D055585:Physical Phenomena; D010825:Physics; D012016:Reference Values; D014055:Tomography, Emission-Computed / Q000295:instrumentation / Q000379:methods*