In the determination of tritium concentration in the natural waters, a reliable efficiency correction could be accomplished using cent roid channel values of the respective Compton spectra. The Compton spectra due to external irradiation with137Cs-gamma ray source shift toward the low energy side depending on the strength of quenching effects in scintillator solution. It was found that the centroid channel values evaluated from the spectra are linearly correlated to the detection efficiency of tritium. The proposed correction method of counting efficiency using the centroid channel values has proved to be superior to the external standard channel ratio (ESCR) method in the case of the external irradiation. Subsequently, the authors have proposed a new correction method which consists of simultaneous tritium beta-ray and alpha-particle spectrum measurements using liquid scintillator solution; the latter is derived from added internal tracer of210Po.It was confirmed that the shift of the peak channel due to the single alpha-spectrum of210Po, appearing at higher energy side, is linearly correlated to the detection efficiency of the co-existing low-level tritium without any disturbance of tritium beta-ray counting. The internal alpha-standard method using alpha emitter can be effectively applied to the accurate measurement of low-level tritium without any intrinsic problems related to the physico-chemical changes of measuring scintillator specimens and the hysteresis of photomultiplier which were encounted in the external standard method.
Bone marrow scintigraphy with indium chloride (111In) was performed in fifty-one patients with the hematological diseases. The results of the investigation were that (1) in all patients, as well as in patients with aplastic anemia, no correlation was there between the degree of the indium chloride accumulation and peripheral blood counts, (2) in patients with aplastic anemia and pure red cell aplasia (PRCA) a tendency to reduction in uptake of indium chloride in bone marrow, (3) in patients with these two good correlation between the degree of indium chloride accumulation and histology of the erythroid bone marrow, but in patients with chronic myelocytic leukemia (CML) and atypical leukemia no correlation between the two, so it seemed unlikely that indium chloride should reflect the effective production of erythrocytes, (4) four patients with leukemia were studied with indium chloride bone marrow imaging two times to evaluate their responses to chemotherapy, and peripheral expansion was no change or reduced in two patients with acute myelocytic leukemia (AML) and one patient with acute lymphocytic leukemia (ALL) who obtained complete remission, but on the other hand, it enlarged in one patient with acute myelocytic leukemia who obtained partial remission, and (5) in two patients with chronic myelocytic leukemia it enlarged up to the ankle joints, which was considerably specific.
The rate of clearance (K value) of99mTctin colloid in the liver defferentiates normal subjects from liver cirrhosis patients; so99mTctin colloid is as useful as198Aucolloid as a marker of liver function. There are several reports concerning volume estimation using liver scintigraphy. Our original method was devised to measure the effective liver volume by scintigraphy. By combining the K value with effective liver volume, a predictive index was obtained in order to predict the residual liver function before hepatic resection. The index in 24 patients with liver diseases was investigated before hepatic resection. Three of them died due to hepatic failure after hepatic resection. The indices were between 0.40 and 0.45 in two of these three patients and 0.338 in one. Among the patients without hepatic failure, the indices showed more than 0.45 in 19 patients and between 0.40 and 0.45 in two. These results indicate that the limitation of hepatic resection is between 0.40 and 0.45 of the predictive index.
This paper describes a software package that manages dosimeter inventory and exposure data with a personal computer. The computer, connected with the access control system, deals with both records of the film badge (FB) supply to workers and the ordering of new FB for a company, processes exposure data and produces reports. The software not only ensures accurate reports but also significantly reduces the tedious labour involved in managing the control system.
The gamma irradiation system with variable effective half-life function has been developed, which provides the low dose rate gamma irradiation field by two137Cs sources (3.7×1010Bq and 7.4×1011Bq) . This apparatus was designed to give an exposure at varying low dose rate in accordance with a biological half life of radioactivity in organisms by selecting one of two irradiation methods. The first irradiation mode uses the spatial attenuation by four movable irradiation tables and the other uses the radiation attenuation by an iron filter. Both of these are driven by pulse motors using the personal computer control. The characteristics on spatial gamma-ray irradiation field were measured using calibrated ionization chambers for gamma dose and NaI (Tl) scintillation ionization chambers for gamma dose and Nal (Tl) scintillation counter for gamma spectra. The irradiation field covers the dose rate between 2.5×10-3C kg-1min-1and 1.2×10-7C kg-1min-1. The energy spectrum information including scattered radiations are also obtained. The apparatus was proved to be useful in the experiments for the irradiation of mice at varying dose rate to simulate tritium in internal irradiation.
The patients receiving maintenance hemodialysis were divided into two groups in the absence and the presence of bone pain and investigated the markers of bone pain in these patients. These results suggested that the duration of receiving hemodialysis, serum cont rations of alkaline phosphatase, osteocalcin and parathyroid hormone became to be the markers of bone pain.
Two antibody method of aldosterone RIA kit was investigated. This kit was measured directly without extracting the aldosterone. On fundamental studies, stability of standard curve, reproductivity, recovery test and dillution test were obtained good results. On clinical studies, the diurnal variation of serum aldosterone concentration in normal child and adult was correlated well to that of concentration of cortisol and ACTH. The concentration of three hormones was the highest in the early morning and it was the lowest in midnight.
The“sandwich”or noncompetitive reagent-excess, 2-site immunoradiometric assay (2-site IRMA), ELISA, USERIA, and related techniques, have several advantages compared with the traditional or competetive radioimmunoassays. IRMAs can provide improved sensitivity and specificity. However, IRMAs present some practical problems with nonspecific binding, increased consumption of antibody, biphasic dose response curve, (high dose hook effect), and may require special technieues for dose response curve analysis. We anticipate considerable growth in the popularity and importance of 2-site IRMA.