Storage-phosphor autoradiography: a rapid and highly sensitive method for spatial imaging and quantitation of radioisotopes.
This study evaluates a storage-phosphor imaging system for rapid autoradiography and quantitation of beta- and gamma-ray emitters in mice. Known quantities of authentic 3H, 14C, and 195mPt (0.06 to 31,714 DPM/mm2) were exposed to imaging plates of the storage-phosphor system for 0.5 min to 15 hr at room temperature. Immediately after exposure, the imaging plates were scanned and the autoradiograms were quantified. Radioactivity as low as 1.8 DPM/mm2 (3H), 0.06 DPM/mm2 (14C) and 3.1 DPM/mm2 (195mPt) was visualized and quantified in 8 hr (3H and 14C) and 6 min (195mPt), respectively. The system displayed a linear range of four to five orders of magnitude (14C: 0.5 to 6,914 DPM/mm2 for 2-hr exposure; 3H: 1.8 to 15,372 DPM/mm2 for 15-hr exposure; and 195mPt: 66 to 198,000 DPM 6 min-exposure). Variation from scan-to-scan was small (< 1% to 5%) and was more pronounced at the lower detection limits and exposure periods. Similar sensitivity, linearity, and variability were obtained in cryosections of murine tumors treated with 14C-fluorouracil or 3H-epinephrine and whole-body autoradiograms of mice treated with 195mPt-cisplatin via liver. The high sensitivity allowed noninvasive imaging of live unanesthetized mice treated with 195mPt with a short exposure time (105 sec). These results validate, for the first time, the high sensitivity, linearity, and wide dynamic range of storage-phosphor technology for quantitative autoradiography of 14C, 3H, and 195mPt isotopes. Storage-phosphor imaging will be useful in rapid quantitative autoradiographic disposition studies of radiolabeled drugs and excipients in vitro and in vivo.
Kanekal
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Matrix Pharmaceutical Inc., Menlo Park, California 94025, USA.
Sahai
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A
Jones
R E
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Brown
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D000818:Animals; D001345:Autoradiography / Q000379:methods*; D002250:Carbon Radioisotopes; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D051379:Mice; D008809:Mice, Inbred C3H; D009374:Neoplasms, Experimental / Q000188:drug therapy; D010758:Phosphorus
D002250:Carbon Radioisotopes; D010758:Phosphorus; D005472:Fluorouracil; D004837:Epinephrine