Quantitative autoradiography with radiopharmaceuticals, Part 2: Applications in radiopharmaceutical research: concise communication.
We describe the application of macroautoradiography, a relatively simple, quantifiable method for the evaluation of positron-emitting and gamma-emitting radiopharmaceuticals. We have investigated the response properties of two types of film to positron (F-18) and negatron (C-14) emitters. Variations in the response of film to increasing film-to-source distance are described, along with the effects of different intensifying screens and mounting tape. Digitization of whole-body autoradiograms (WBARG) in small animals was performed by using a videodensitometry system (videocamera interfaced to a computer). Quantitation was derived from analysis of a series of step-wedge standards that covered the range of radioactivities in the sample. By using a close-up lens on the videocamera, a 2- by 2-cm field is digitized as a 128 X 128 array, each pixel representing 156 X 156 micron. The effect of chlorpromazine (CPZ) on glucose metabolism in mice was studied by giving C-14 2DG followed by CPZ and F-18 FDG in the same animal. Muscle activity decreased and brown-fat activity increased. The high spatial resolution of this technique enables quantification in structures as small as the basal ganglia in mice. The use of dual-nuclide ARG permits each animal to be its own control, which greatly increases the utility of this method.
D000818:Animals; D001345:Autoradiography; D002250:Carbon Radioisotopes; D002746:Chlorpromazine / Q000494:pharmacology; D003720:Densitometry / Q000295:instrumentation*; D005069:Evaluation Studies as Topic; D005461:Fluorine; D005947:Glucose / Q000378:metabolism; D051379:Mice; D008905:Minicomputers; D011868:Radioisotopes; D051381:Rats; D013679:Technology, Radiologic; D013690:Television; D014018:Tissue Distribution; D014915:Whole-Body Counting
D002250:Carbon Radioisotopes; D011868:Radioisotopes; D005461:Fluorine; D005947:Glucose; D002746:Chlorpromazine