Radiology, Vol 133, 497-500, Copyright © 1979 by Radiological Society of North America
Feasibility of absolute activity measurements using the Cleon emission tomography system
MA Flower, RP Parker, IP Coles, RA Fox and NG Trott
Large volume and small discrete sources of Tc-99m were used to study the
spatial resolution, sensitivity, linearity and reproducibility of the
radionuclide brain images. The spatial resolution is constant both within
and perpendicular to the section. For uniform distributions of activity the
response is uniform over the field of view, and the mean pixel count rate
is a linear function of the radioactive concentration and is independent of
the diameter of the source. However, for discrete sources, the sensitivity
was found to vary with the position of the source, and the potential of the
system for quantitative assessment of the uptake of radioactivity in organs
and tumors was limited initially. Later studies, with modified software,
show that this undesirable effect has been reduced.
