An electron spin resonance(ESR) spectroscopic study was performed on the radicals induced in irradiated fresh mangoes. Fresh Philippine mangoes were irradiated by the γ-rays, lyophilized and powdered. The ESR spectrum of the dry specimen showed a strong main peak at g=2.004 and a pair of peaks at both magnetic fields of the main peak. The main peak detected from flesh and skin specimens faded away in a few days after the irradiation. On the other hand, the side peaks showed a well-defined dose response even 9 days after the irradiation. The side-peak is a useful mean to define the irradiation on fresh mangoes.
Analysis of irradiated insects using Electron Spin Resonance(ESR) spectroscopy was reported. The insects were maize weevil, red flour beetle, Indian meal moth and cigarette beetle that are hazardous to crops. The ESR spectra were consisted of a singlet at g=2 and a sextet centered at the similar g-value. The singlet signal is due to an organic free radical. The sextet signal is attributable to the hyperfine interactions from Mn2+ ions. Upon irradiation, new signals were not detected. The relaxation times, T1 and T2, showed no variations before and after irradiation.
Short-term measurements of indoor radon concentrations were made in a dwelling in Okinawa, Japan, in which high radon concentrations had been observed in a previous nationwide indoor survey. Measurements were carried out in 4 locations:the bedroom, living room and outdoors. In this study, anomalously high radon concentrations were observed in the 1st-floor bedroom and the mean radon concentration averaged about 400Bq m-3 during the observation period, much higher than Japan's annual average of 15.5Bq m-3. A diurnal pattern of extreme fluctuation was found. Furthermore, there was a noticeable spatial distribution of indoor radon concentrations.
Irradiation facility for potato at Shihoro in Hokkaido has been operated for more than thirty years on the bases Fricke dosimetry system. The system is homemade, therefore, it has a probability of low reproducibility among individuals. While alanine dosimetry system is commercially available now and used widely. This study was conducted to confirm that the alanine dosimetry system can be used equally as the Fricke dosimetry system, demonstrating surface dose mapping of potato irradiation container in the facility. During operating practice, the measurements were performed in January and March 2009, in which the May Queen potatoes and the Baron potatoes were irradiated respectively. In this study, the uniformity, maximum dose and minimum dose were 1.08, 149.1Gy, and 137.3Gy, respectively. The positions of dosimeter at maximum values were located at intersection range of a vertical line and middle of horizontal lines(20cm to 60cm from top) of the container. Those results correspond to specification of the design concept for the irradiator and show the alanine dosimetry system can be use for dose distribution measurement system as well as Fricke system, considering the facility has been operated as designed for more than 30 years.
The temperature dependence of NaI(Tl) scintillation spectrometer(2"×2"φ and 3"×3"φ)was investigated in the temperature range of practical operation. The instrument was set in the thermostatic chamber and the temperature was changed by 5°C interval. As the result, the drift of peak position of gamma-rays from 40K and 208Tl was found. We measured environmental radiation in the open air with thermometer to approach the subject in a practical influence. We found that the problem in the temperature dependence of NaI(Tl) scintillation spectrometer was not only the drift of pulse height distribution but the deterioration of energy resolution. To improve these problems,we proposed a simple method to correct pulse height distribution.
Concentrations of artificial and natural radionuclides, such as 134Cs, 137Cs and 40K in 49 dried herbs marketed in Saitama were analyzed by gamma-ray spectrometry. No 134Cs was detected. On the other hand, 137Cs concentrations were ranged from 2.1 to 240Bq/kg-dry in 10 dried herbs imported from Europe. 40K level was 99.9-1400Bq/kg-dry in all dried herbs. Obvious regional differences of 137Cs concentrations of “eyebright” between Polish product and Bulgarian were observed. The committed effective dose of 137Cs by annually drinking a cup of herb tea in adults was estimated to be about 1.0×10-3mSv and the contribution of 137Cs is proved to be very small in this study.
Background:18F-fluorodeoxy-glucose(FDG)-positron-emission tomography (PET) often shows negative for tumors with low grade malignancy. On the other hand, 11C-acetate(AC)-PET has been known to be able to detect well-differentiated lung adenocarcinoma, prostate cancer, and well-differentiated hepatocellular carcinoma, which are often negative for FDG-PET. Here, we show our recent study which compare the detection rate and ability for prediction of malignancy grade of lung adenocarcinoma between acetate and FDG-PET. Methods:227 Non-small cell lung cancer(NSCLC)and 56 benign nodules were examined by both AC- and FDG-PET before surgery. The sensitivity and specificity for discriminating benign/NSCLC were compared between AC- and FDG-PET. The AC- and FDG-uptakes were examined to determine the relationship with tumor aggressiveness, i.e. pathological tumor stage, lymphatic, vascular, or pleural involvement. Acetate or FDG uptake was calculated by the ratio of SUV(SUV-CR) between the tumor the corresponding point of contralateral normal lung. Results:The sensitivity for detection of NSCLC was 0.71 with AC-PET, which was significantly higher than 0.57 with FDG-PET(p<0.001). There was no significant difference of specificity between the two. In the 146 lung adenocarcinoma, the sensitivity for detection of adenocarcinoma was 0.62 with AC-PET, which was significantly higher than 0.37 with FDG-PET(p<0.001). However, there was no significant difference of sensitivity between the two in 51 moderately differentiated adenocarcinoma and 30 poorly differentiated adenocarcinoma. In 169 clinical T1N0M0adenocarcinoma, while tumors with lymphatic or vascular invasion showed higher FDG-uptake than those without(p=0.04-<0.001), AC-uptake did not show significant difference between tumors with and without lymphatic or vascular invasion. Conclusions:While AC- and FDG-PET were similar for the detection of moderately- or poorly-adenocarcinomas, the former was superior to the latter for the detection of well-differentiated adenocarcinomas. For prediction of tumor aggressiveness of clinical stage IA lung adenocarcinoma, AC-PET was inferior to FDG-PET.