Soils were extracted with 6N hydrochloric acid containingPb, Csand Sr carriers.137Csand90Srwere separated, and thenPbin the residual solution was separated as sulfide and radiochemically purified. After the addition ofBicarrier and the achievement of radioactive equilibrium, Bi was separated as oxychloride and submitted to radioassay. This radioactivity was identified as that of210Bi.Therefore this method was considered as a useful one for radiochemical analyis of210Pbin soil. By the application of this method, the following results were obtained: 210Pbwas distributed mostly within soil profiles reaching down to 15 cm. The trend of vertical distribution was almost the same also for90Srand137Cs210Pbcontent was higher in phosphate rocks than in soils. But a hypothetical pathway, along which210Pbin phosphate rocks contaminates soils as an impurity of phosphate fertilizers, was not considered to make an important contribution to the ground deposition of210Pb.
The authors have previously reported a tracer method for measuring engine oil consumption using beaded plastic scintillation detector and oleic acid sulfide containing35S.Measurement of engine oil consumption has usually been made under constant engine operating condition. The data thus obtained, however, cannot be said to give a real state of oil consumption of the engine which is frequently accelerated and decelerated in actual driving. So it was required to develop a bench test which made it possible to measure oil consumption in transient engine operation. To meet this requirement, response time of the measuring apparatus should be shorter than 10 seconds. The apparatus, previously reported, had a longer response time, because of longer duration needed for homogenization of reacted absorbing solution. A measuring system with quick response was developed. The exhaust gas from an engine was completely burned in an oxidizing furnace, and brought into contact with aqueousH2O2solution in a reaction tube, where35SO2was converted intoH235SO4solution. TheH235SO4solution was constantly pumped into a beaded plastic scintillation detector and its radioactivity was continuously measured. Because about 2.6 cc ofH2O2solution was enough to capture all theSO2involved in a litre of the exhaust sample gas, it was possible to obtain a solution with higher specific radioactivity than by conventional absorbing tube. When the flow rate ofH2O2solution, specific activity of engine oil and sampling speed of exhaust gas were kept constant, the oil consumption rate was changed in proportion to the product of specific activity of absorbing solution and exhaust gas speed of the engine. So the oil consumption rate was observed on the spot by processing these data on a computer. One of the findings from this measurement was that oil consumption rate increased immediately after acceleration.
A simplified digital image processing of photoscintigrams was performed by data acquisition with CCTV re-scan and by data processing with a small computer. Scanned TV picture signals are sampled, digitalized, in sequence, and stored in the memory of the computer. Sampling pulses are generated by a time delay unit built in an oscilloscope. The timing of sampling pulses is controlled by the computer programs. Some of the fundamental characteristics of this method were examined by the use of a test chart. They were, a flatness of sensitivity and a linearity in gray scale of vidicon tube. When characteristics of a vidicon tube are measured, they could be compensated by computer processing. As the result of sampling, an image is divided into 70×50 or 3, 500 points. After the compensation for a TV tube characteristics, various kinds of data processing were performed according to the diagnostic requirement. Some of the result in the cases of thyroid and liver are presented. Digital image processing has much more flexibility than analog processing.
Absorption, distribution, excretion and metabolism of naproxen [d-2- (6-methoxy-2-naphthyl) propionic acid] in mice, rats and human were studied with14C-labeled naproxen. When14C-naproxen was administered intravenously and orally to mice, the highest concentration of the radioactivity in whole body autoradio gram was observed in the blood and high in the liver, lung, kidney and moderate in the adrenal cortex, skin and connective tissues, but scarcely detectable in the central nervous system and thymus. The pattern of distribution of the radioactivity in the fetus was similar to that of the maternal tissues, but no accumulation in fetus 6 hours administration was found. When the tissue distribution of radioactivity in mice and rats was determined quantitatively, the blood concentration was the highest and its half life about 3 hours both on the oral administration and intravenous injection in rats, which was similar to the findings of the whole body autoradiogram of mice. It is shown that the majority of the radioactivity existing in the blood is unchanged compound and that about 97% of it is bound to serum protein in rats after the oral administration and about 99% is bound in human serum in vitro. The radioactivities which were excreted in the 72 hour-urine and feces after oral administration to rats of14C-naproxen were 84% and 11%, respectively and 48% of the administered radioactivity was excreted in the 24 hour-bile. About 95% of the radioactivity up to 72 hours after oral administration to human was excreted in the urine. Approximately 48% of the urinary radioactivity of rats was present in the form of 6-hydroxyl naproxen and about 19% was conjugates of 6-hydroxyl naproxen and 31% was conjugates of naproxen, but unchanged naproxen was only 2% of the urinary radioactivity. On the other hand, the percentages of unchanged drug and 6-hydroxyl naproxen in the biliary radioactivity were about 75% and 1.3%, respectively.
This study was undertaken to clarify the suitability of198Au-colloid andNa251CrO4for a marker of transit in the gastrointestinal tract. The distribution, the excretion into the feces and urine, the absorption and excretion through the gastrointestinal tract were investigated in mice by means of sample measurement and whole body autoradiography. Orally administered198Au-colloid was not absorbed from the gastrointestinal tract and all was excreted into the feces.198Au-colloid was not adhered to the gastrointestinal mucosa and consequently, the excretion into the feces was not delayed. On the other hand, orally administeredNa251CrO4was relatively well absorbed from the gastrointestinal tract, distributed to the whole body and a part of it was excreted into the urine. Intravenouslly injectedNa251CrO4was excreted into the gastrointestinal tract. It is concluded from the results obtaind that198Au-colloid is available for a marker of gastrointestinal transit butNa251CrO4is unavailable.
87mSrbone scintigraphy was performed in 22 cases of bone metastasis or suspected bone metastasis of malignant tumors and 1 case of necrosis of the head of the femur. This mini-scanning method showed abnormalities in 4 out of 6 cases in which bone metastasis was demonstrated by roentgenography. No abnormalities were observed in 15 out of 16 cases in which no abnormalities were seen by roentgenography. Abnormalities were observed in the lesion in one case of necrosis of the head of the femur as indicated by roentgenography. The mini-scanning method with87mSrfailed to demonstrate any abnormalities in 3 out of 23 cases. Causes for these failures were examined, discussing problems of the mini-scaning method and of the use of87mSras radioisotope for scintigraphy.