Using phantom images, the adaptation of texture analysis was evaluated in analyzing the scintigrams. Prior to analyse the scintigrams, image data acquisition and preprocessing to degrade statistical noise of pixel counts must be performed. Feature parameters which represent RI distribution should be selected on texture analysis of the scintigrams. Using the feature parameters extracted from probability of pixel counts, the more ununiformity became in RI distribution, the less energy became, but mean, variance, skew and entropy became larger values. When discriminant analysis was done using the textural features, ratio of correlation was 0.998, and accuracy of classification on phantom images which were difficult to be classified visually became 58-83%. The textural features was estimated to be useful quantitative data, when the scintigrams was read visually.
The relation between the blood clearance and hepatic uptake of99mTc-phytate (99mTc-P) and the severity of hepatic injury was investigated by using the dogs induced hepatic injury with carbon tetrachloride (CCl4), D-galactosamine (GalN), α-naphthylisothiocyanate (ANIT) or DL-ethionine (EthN) . After the administration of hepatotoxins, serum GPT activity increased and the blood clearance rate of99mTc-P and the hepatic uptake ratio of99mTc-P decreased with the increase of dose level. The degree of increase in serum GPT activity compared with the control value was in the order: GalN>CCl4>ANIT≅EthN, the degree of decrease in the blood clearance rate of99mTc-P was in the order: GalN>CCl4>ANIT>EthN, and the degree of decrease in the hepatic uptake ratio of99mTc-P was in the order: GalN>CCl4>ANIT≅EthN. These results suggest that the disorder in the hepatocytes may be one of causes for inducing the decrease in the hepatic uptake of99mTc-P, and the consequence of this decrease may induce the decrease in the blood clearance of99mTc-P.
A simple and reliable method for determination of222Rn in natural water has been developed by using gamma ray spectrometric measurement and a sample container particular designed. Samples were directly measured by a Ge detector coupled with the multichannel pulse height analyzer. The activities of222Rn were determined by the area of 352 keV photopeak of214Pb. At the same time, in order to evaluate the accuracy of this method, the activity of222Rn in the same water sample extracted by organic solvent was measured by liquid scintillation counting (LSC) method. The observed activity of222Rn measured by our method agreed with that by LSC method.