The method for the preparation of52Fe in practical scale for medical use by the3He-bombardment on natural chromium using the 160-cm cyclotron has been developed and discussed. The target consists of a 2×7×0.05 cm3layer of pure chromium electroplated onto pure copper backing plate (5×9×1cm3) . A 2 hr bombardment at 40 MeV at beam current of 20 μA yields about 2 mCi of52Fe at the end of bombardment. After 1-5 hr bombardment, the chromium layer was dissolved into 130-150 ml of 9 N hydrochloric acid (80°C) . Then the solution was transferred into a separating funnel, into which O2-gas was bubbled for about 5 min. Then 1 ml of Br2-water was added and the bubbling continued for 3-5 min to complete the oxidation of52Fe (II) to52Fe (III) . From the resulting hydrochloric acid solution (8 N), the52Fe (III) was extracted with two 80 ml portions of di-isopropyl ether. The ether layers were combined and the52FeC13was back-extracted with two 30-50 ml portions of distilled water. Then the52Fe (III) was reduced to52Fe (II) with 5-6 mg of ascorbic acid and finally prepared a52Fe (II) -citrate solution for medical use. Thus the52Fe was obtained in a sufficient radiochemical and chemical purity, within about 1 hr, and the total yields proved to be 90-92%. The specific activities for 2-3 mCi of52Fe were determined 20-30 μCi/μgFe.
The effect of addition of inorganic acids or alkalis on gelation of polyvinyl alcohol aqueous solution by γ-ray irradiation was studied. The gelation doses decreased in addition of hydrochloric, perchloric, sulfuric, or phosphoric acid, and increased in addition of sodium hydroxide or ammonia water. The acceleration by addition of the acids and the retardation by the alkalis may be explained by increase and decrease of the yield of H radicals from radiolysis of water, respectively.
Instrumental neutron activation analysis by γ-ray spectrometry with a high resolution and large volume Ge (Li) detector followed by automatic data analysis with an electronic computer was applied to elemental analysis of airborne dust samples which were collected at four stations selected in Osaka and Sakai cities. Monthly average concentrations of various elements were determined during the period from March 1970 up to March 1971. For most elements, the highest concentration appeared in November to December and the lowest in August. A somewhat lower peak concentration appeared around June. Such a seasonal variation can be ascribed mainly to the meteorological conditions in Osaka district. Changeful variation was observed for several elements such as Zn, As, Se, Sb and Th, and was presumed to be closely related to industrial activities. Conspicuous area dependency was found, especially for concentrations of Se, As, Ba, La and Th. The main pollution source of Br is possibly the gas discharged from automobiles. Instrumental neutron activation analysis which easily makes it possible to get information about the abundance of so many elements will be quite effective fnr grasping the situations of air pollution.
The elementary determination of nail clippings has almost been not worked, but it is well known that there are changes in the levels of some elements in nails of patients of cystic fibrosis of the pancreas and congenital cyanotic heart disease with clubbed fingers. The purpose of this study is to establish the analytical procedures of nails by using neutron activation analysis. Nail and standard samples were irradiated in KUR (Kyoto University Reactor) at a flux of 2.75×1013 thermal neutrons/cm2/sec and irradiation time was 60 minutes. After irradiation, nail samples were analysed by non-destructive and destructive methods, and sodium, manganese and copper contents in nail samples were obtained. Manganese and copper were adequately separated by using ion-exchange column (Dowex I×8) from sodium which was the most interfering element when activation analysis of biologic specimens were tried. Mean sodium, manganese and copper values in 8 nail samples obtained from non-destructive methods were respectively 6.47×102 Naμg/g, 1.42 Mnμg/g and 2.97×101 Cuμg/g, mean sodium value measured after heating and dissolving was 6.72×102 Naμg/g, and mean manganese and copper values obtained from destructive methods were 1.30 Mn, ccg/g and 2.19×101 Cuμg/g. A mean of each ratio of sodium values in 8 nail samples obtained from non-destructive measurements to its values measured after heating and dissolving was 1.13 times and the standard deviation was ±0.10. Those of manganese and copper values in 8 nail samples obtained from nondestructive methods to destructive methods were respectively 1.00 and 1.42 times with standard deviations of ±0.11 and ±0.43. The mean percentage of yields of manganese and copper were 99.6% and 90.1%.
We examined fundamental and clinical studies of kidney by 203Hg-Salyrgan and the results were obtained as follows. We know that the chief distributed organ of 203Hg-Salyrgan is the kidney and on the autoradio gram the blackend dots there are predominantly into the distal tubuli. Disappearance of 203Hg-Salyrgan from blood stream in the normal adults gets to half within 16 min and in the patients with renal diseases the disappearance to half takes longer. The rate of prolongation were almost parallel with severity of illness. It seemed reasonable that the simultaneous combination of nephrography and scintiphotography by 203Hg-Salyrgan would also supply the information of the renal function that could not be obtained from the usual procedure alone. We think that the method of 203Hg-Salyrgan is a kind of the most useful research technique for evidence of the damage in renal parenchyma with the low exposure dose in kidney tissues.