Semi-quantitative method of IV isopropyl- (123I) -p-iodoamphetamine (123I-IMP) accumulation in cerebrum by using123I-IMP SPECT was tried. Ratio of counts in whole cerebrum to those in normal cerebellum was calculated, and this accumulation is defined as cerebrum to cerebellum accumulation ratio. In group of patients with dementia or patients who were remaining in bed, significantly low accumulation ratio was observed, while in “normal” group, no differences in sex and aging were observed. Calculations of cerebrum to cerebellum accumulation ratio was concluded as a useful method of evaluating the accumulation of123I-IMP in cerebrum.
The analysis of kinetic rate constants in the compartment model for [18F] fluorodeoxyglucose (FDG) was undertaken. Four kinetic rate constants were determined with a least square fitting package SALS (Statistical Analysis with Least Squares), using the measured data of18F activity as a function of time. SALS calculations were found to be easy and quick with high precision. The rate constants and the curves fitted by the k3and the k4models were compared in situations with various degree of cerebral glucose metabolism during positron emission tomography (PET) studies. The k4model in the determination of cerebral metabolic rate for glucose (CMRglu) was much superior than the k3model in any given situation as it always underestimates the metabolic rate. However, the k3model produces less variation when the cerebral radioactivity curve shows steady rising pattern.
We studied on the basic performance of a nonextraction coated tube RIA kit, DPC Aldosterone kit (Nippon DPC Corporation) . 1. The average binding CVs of the calibrators (25 to 1200 pg/ml) were stable in a range from 1.4 to 1.9%. 2. The minimum sensitivity was 17 pg/ml from 2SD method of 0 calibrator. 3. The intra-assay reproducibility test showed an average CV as 9.0%, and the inter-assay test showed as 8.8%. 4. The recovery ratios of a recovery test were 85.4 to 121.6%. 5.The correlation test with another maker's kit showed a correlation curve as y=0.970 * x+19.68 and a correlation coefciency as r=0.970. 6. The normal range, the correlation between fasting recumbency and daytime sitting, and the correlation between walking and resting, showed similar results as former reports.