Accuracy of bone mineral measurement by the dual photon absorptiometry (DPA) was studied in comparison to ashed bone mineral (ash) on the lumbar spine of 23 cada vars. There was a high correlation (r=0.896) between the value of DPA and ash weight. Bone mineral content in the radius by the single photon absorptiometry (SPA) did not correlate to bone mineral density (BMD) by DPA in the patients with hemodialysis. SPA may be less useful to assess BMD of the whole body. Fat mass and lean mass measured by DPA were well correlated to the value obtained by the electrical impedance method. Precision in measurement of fat mass and lean mass was also confirmed by the electrical impedance method. These results suggest that DPA has a high precision for measurements of the bone mineral and the body composition.
To evaluate the usefullness of a new radiotracer, 99mTc methoxy isobutyl isonitrille (99mTc-MIBI), rest and stress99mTc-MIBI myocardial single photon emission computed tomography (SPECT) were compared with stress201Tl myocardial SPECT in the same 10 effort angina pectoris patients with only left anterior descending artery (LAD) stenosis. In the stress scan, the number and the severity of abnormal segments in LAD territories were higher by201Tl than those by99mTc-MIBI. Sensitivity in the detection of abnormality by99mTc-MIBI was as high as that by201Tl (90% vs. 100%) . However, specificity by99mTc-MIBI tended to be higher than that by201Tl (70% vs. 55%), because the more false-positive segments were observed in201Tl SPECT, In comparison of images between rest scan by99mTc-MIBI and delayed scan by201Tl, the rate and degree of normalization in99mTc-MIBI SPECT was higher than those of redistribution in201Tl SPECT. Thus, our results indicate that99mTc-MIBI myocardial SPECT was more reliable than201Tl for the evaluation of the extent of ischemic lesion or viable tissue in the ischemic heart disease.
Three methods were used to obtain dose distribution inside human body : experimental, semiempirical and numerical. The computer code was developed for calculations of dose equivalents in 23 organs of adult mathematical phantom for photon energies from 10 keV to 150 keV. The X-ray spectra were measured for 5 types of X-ray sets by using NaI (Tl), Si (Li) and Ge (Li) detectors. The organ doses and effective dose equivalents were determined for 47 types of X-ray diagnostic examinations. It was shown, that the estimated effective dose equivalent is 1.4 mSv/person-year due to medical irradiation for the population of the USSR.
67Ga tumor scintigraphy was attempted in a hamster, using a pinhole collimator improved for small animal scintigraphy, to examine whether DMBA induced experimental cheek pouch carcinoma could be demonstrated or not. The spot scan maxillofacial images cleary showed the fine uptakes of67Ga in the carcinoma lesions. The results obtained from this modality could be apllied in the experimental studies on DMBA induced cheeck pouch carcinomas, and that the most desirable images were obtained under the condition of exposure 400, distance 0 cm and counts 400 kc.
Myocardial SPECT imaging using123I-MIBG was performed in 29 patients with cardiac disorders and compared with the results of201Tl SPECT imaging. The areas with decreased uptake of123I-MIBG was usually more extended than those observed with201Tl SPECT, which was more prominent in the delayed scan than in the early scan. In the 2 patients out of 4 with hypertrophic cardiomyopathy, the distribution of123I-MIBG and201Tl was not matched. Namely, high uptake of123I-MIBG was observed in the regions with low201Tl uptake. The washout rate for123I-MIBG was higher in the region with decreased myocardial wall motion than those with preserved wall motion.