Quantitative analysis in single photon emission tomography (SPET)

Abstract

Quantitative analysis can improve the sensitivity and specificity of single photon emission tomography (SPET) procedures, as well as reduce inter- and intraobserver variabilities. Quantification of the radioactivity distribution is the ultimate goal of SPET. In this review we consider the basic requirements for an optimum three-dimensional reconstruction of the radionuclide distribution to enable quantification. Attenuation and scatter correction as well as varying resolution are the major problems. In the older SPET systems quantification was hampered by the lack of system sensitivity and sufficient computer power. Therefore, the imaging system was often assumed to be shift invariant and linear and the attenuation throughout the object uniform. More sophisticated solutions have been proposed and with more or less success implemented, but not for application in daily practice. Knowledge (measurement) of the attenuation is often required. New generation SPET systems employing multi-detectors and super minicomputers will ease the implementation of these solutions.

Validation of quantitative brain dopamine D2 receptor imaging with a conventional single-head SPET camera

“…Therefore the uptake ratios obtained with different equipment in different laboratories are not directly comparable. A comprehensive review of the physical elements of quantitative SPET has recently been published by Blokland et al [7].…”

Central benzodiazepine receptor imaging and quantitation with single photon emission computerised tomography: SPECT

“…The sequence of images (projections) taken from angles around the head is the basic data required for the formation of SPECT images. By a process of image reconstruction (Blokland, Reiber and Pauwels, 1992;Blokland, 1994), the computer combines these multiple projections to produce a picture of radioactivity within a given brain slice.…”

“…SPECT is cheaper and is becoming more available in both clinical and research settings. The main SPECT developments in the last decade or so have been directed towards improving the counting capabilities and spatial resolution of systems (Bailey et al, 1994), the ultimate aim being quantitative imaging using appropriate radioligands (Blokland, Reiber and Pauwels, 1992;Blokland, 1994).…”

Automatic quantification of three-dimensional kinetic energy in gated myocardial perfusion single-photon-emission computerized tomography improved by a multiresolution technique

“…Defects on the distribution of some radionuclides such as 201 TI and 99m Tc-MIBI in the myocardium indicate a muscle hypoperfusion due to obstruction of the coronary arteries. 2,3 Electrocardiographic gating of MIBI SPECT images provides the additional ability to determine the severity of abnormalities in wall motion and wall thickening associated with myocardial infarcts. 4,5 While gated SPECT studies are usually interpreted as series of 2-D images, there is an increasing interest in the presentation of the data in a more realistic 3-D form.…”