Multi-parallel hole collimators are generally used with a gamma camera. The purpose of this study is to determine the relationship between the collimator position of the gamma camera and its spatial resolution. When the collimator is attached to the camera head, the smaller the distance between the collimator and the crystal face, the better the spatial resolution will be. But, for a set of source to crystal distance, the distance between the source and the collimator makes minimal changes in the spatial resolution. Therefore, when the source position is far from the collimator face, for example 20 cm, the system spatial resolution is minimally affected by the distance between the collimator and the crystal face.
In order to know the relationship among some elements in biological materials, iodine, bromine and chlorine concentrations in cow's milk samples in Japan were determined by the thermal neutron activation analysis using a low power research reactor and a Van de Graaf accelerator. The iodine contents in cow's milk samples ranged from 0.041 to 0.316 ppm with an average of 0.096 ppm. The bromine and chlorine in these samples ranged from 2.3 to 11.1 ppm and from 475 to 1 650 ppm, respectively. The average concentration of the bromine was calculated to be 5.6 ppm and that of the chlorine was 853 ppm. The relationship among iodine, bromine and chlorine concentrations in cow's milk samples in Japan was studied with a regression analysis. It was suggested that the correlation has a power function as follows; Y=K (Z) -A where, Y is elemental concentration in ppm, Z is atomic number of element, A (=7.4) is exponent and K (=14.7) is a constant.
A technique of autoradiography using solid state track detectors is described by which spatial distribution of radioactivity in an alphacounting source can easily be visualized. As solid state track detectors, polymer of allyl diglycol carbonate was used. The advantage of the present technique was proved that alpha-emitters can be handled in the light place alone through the whole course of autoradiography, otherwise in the conventional autoradiography the alpha-emitters, which requires special carefulness from the point of radiation protection, must be handled in the dark place with difficulty. This technique was applied to rough examination of self-absorption of the plutonium source prepared by the following different methods; the source (A) was prepared by drying at room temperature, (B) by drying under an infrared lamp, (C) by drying in ammonia atmosphere after redissolving by the addition of a drop of distilled water which followed complete evaporation under an infrared lamp and (D) by drying under an infrared lamp after adding a drop of diluted neutral deter-gent. The difference in the spatial distributions of radioactivity could clearly be observed on the autoradiography. For example, the source (C) showed the most diffuse distribution, which suggested that the self-absorption of this source was the smallest. The present autoradiographic observation was in accordance with the result of the alpha-spectrometry with a silicon surface-barrier detector.
We have tried fundamental studies, reference values and relationship to menstrual cycle on Prolactin RIA BEAD II kit which has a method of IRMA using monocronal antibody. On clinical studies, we investigated change of serum prolactin level during the menstrual cycle and relationship to other hormones (LH, FSH, estradiol, progesterone) . It was the result that prolactin level of follicular phase was lower than that of preavulatory phase and luteal phase. We conclude that change of prolactin level during the menstrual cycle is related with change of estradiol level.
A newly established double antibody radioimmunoassay (RIA) was fundamentally and clinically evaluated. Original procedures were partially modified as follows: Sample volume for serum and urine was changed to 25 μl, and thus 200 mg/l of arm standard was prepared using 50μl of o-riginal standard solution (100 mg/l) . The results were satisfactory in sensitivity (0.3 mg/l obtained from -2SD method), intraassay precision with its coefficient variation (CV) ranging from 3.0 to 7.4%, interassay precision with its CV ranging from 3.0 to 10.7%, and recovery with the mean value of 102.4% in serum and 108.2% in urine respectively. There were no changes about αl-m value between diluted (2 times) and undiluted with high concentration samples. Normal levels of αl-m were less than 25 mg/l in serum and less than 10 mg/l in urine. The present results indicate that the determination of αl-m could be very simple and useful for the most sensitive screening test for the evaluation of renal function.