[en] Pulmonary hypertension in mitral valvular cardiac disease has been evaluated in 122 patients by a modified upper lung/lower count ratio using single-pass radionuclide angiocardiography. The mean upper lung/lower lung radio correlates well with pulmonary artery mean (r=0.483) and wedge pressure (r=0.804). After correction surgery of the cardiac valve, the ratio decreases and returns to normal range in patients judged clinically to have good surgical benifit. This modified method using single-pass technique provides additional simple, reproducible and nontraumatic results of regional pulmonary blood flow and appears to be correlated with the degree of pulmonary hypertension in mitral heart disease

[en] Since its introduction 20 years ago, nuclear cardiology in the Republic of Korea has grown impressively and is now widely used as a noninvasive procedure in the diagnosis and functional evaluation of various types of heart diseases. All of the classes of procedures, that is, first-pass radionuclide cardioangiography, gated blood pool scan, myocardial perfusion imaging, and myocardial infarct imaging, are being employed frequently and have been the subject of numerous studies. First-pass radionuclide ventriculography is being used in the detection and quantification of intracardiac shunts, the evaluation of chamber size, function, or cardiopulmonary dynamics in various disease states. With gated blood pool scans, several parameters of cardiac function are being measured in a variety of conditions including coronary heart disease. Quantifications of regurgitations are also being done. Both thallium-201 and technetium-99m pyrophosphate are being used in the diagnosis of coronary artery disease. Besides clinical imaging, active research in the field of nuclear cardiology has also been taking place in the Republic of Korea. Examples include investigations on new imaging agents such as ¹¹¹In-antimyosin monoclonal antibody and hexakis technetium(I) cations, or instrumental developments such as the nuclear stethoscope. Despite such noteworthy accomplishments, however, there have also been some obstacles to further developments in the Republic of Korea, such as the unavailability of a cyclotron. Nevertheless, considering the rate of expansion these procedures are showing and the effort we are putting into further development, the future for nuclear cardiology in the Republic of Korea appears quite promising and may become an example for other developing countries. (author). 28 refs, 5 figs, 2 tabs

[en] Boehmite sols have been prepared by crystallization of amorphous aluminum hydroxide gel obtained by hydrolysis and peptization of aluminum using acetic acid. The size of the boehmite crystallites could be controlled by Al molar concentration in amorphous gel by means of controlling grain growth at nucleation stage. The size of boehmite increases as a function of Al molar concentration. With increasing boehmite crystallite size, the d₍₀₂₀₎ spacing and the specific surface area decreases, whereas the pore volume increases along with pore size. Especially, the pore size of the boehmite sol particles is comparable to the crystallite size along the b axis, suggesting that the fibril thickness along the b axis among the crystallite dimensions of the boehmite contributes to the pore size. Therefore, the physical properties of boehmite sols can be determined by the crystallite size controlled as a function of initial Al concentration

[en] We have analyzed the polar maps of dipyridamole stress/rest ^99mTc-MIBI SPECT and compared the quantitated perfusion defects of dipyridamole stress polar map and the findings of coronary angiography in 56 patients with coronary artery diseases. We performed the same day dipyridamole stress-rest myocardial SPECT, reconstructed the polar maps according to Cedars-Sinai method and quantitated perfusion defects of total myocardium and the territory of each artery, comparing the polar maps of patients with normal files. Stenosis more than 50 percent was considered significant and myocardial ischemic score was calculated as summed score of percents of main coronary arteries. Positive concordance of myocardial SPECT with coronary angiography were 82.6% with left anterior descending artery(LAD), 85.7% with left circumflex artery(LCx) and 78.6% with right coronary artery(RCA). Perfusion defect of SPECT polar map and the stenosis of coronary artery showed the contingency phi of 0.55(p<0.0001) with total arteres, 0.38(p=0.016) with Lad, 0.50(p<0.0001) with Lc and 0.40 (p=0.007) with RCA. Dipyridamole stress percent defect of polar map was correlated with myocardial ischemic score with Spear man's rho of 0.47(p=0.001) in total arteries, 0.48(p=0.001) in Lad, 0.56 (p<0.001) in Lc and 0.38(p=0.002) in RCA. These findings revealed that defect of the dipyridamole stress myocardial ^99mTc-Mibg SPECT and the percent extent of this defect were related with significant artery stenosis of individual arteries and the degree of stenosis. We thought that we could use the defects in the polar map of dipyridamole stress ^99mTc-Mibg SPECT for the quantification of myocardial perfusion decrease.

[en] Recently, because of safety and environmental concerns, there has been a tendency to introduce solid self-lubricating composites for bearing materials. In this paper, we developed Fe-Cr-C-Mn-Cu cast composite alloys as a self-lubricating composite and investigated the effect of carbon on the formation of protective tribofilms during sliding. The wear resistance of these materials was mainly affected by carbon concentrations due to the fact that in particular wear passed from delamination to tribo-oxidation, reducing the wear rate. The improved wear resistance likely resulted from protective tribofilms that formed on the surface during sliding.

[en] Detectable size of the lesions in oncology PET studies is determined by the physical factors, such as the fraction of count recovery within the lesion and background variability. In this study, relationship between these parameters and reconstruction method in 2D/3D PET acquisition was investigated for Siemens ECAT EXACT 47 PET scanner. NEMA IEC body phantom which consisted of 2 large cold spheres (inner diameter: 37 and 28 mm) and 4 small hot spheres (22, 17, 13, and 10 mm) were filled with F-18 solution. The concentration of the background activity in the phantom was 5.3 kBq/mL and those of hot spheres were 4 and 8 times of the background. PET data were acquired for 7.5 min with coincidence window of 12 ns and energy window of 250∼650 keV, and reconstructed using OSEM and FBP algorithms. The measurement was repeated 3 times for each region to background ratio (8:1, 4:1) in 2D/3D PET data acquisition mode. Multiple ROIs were drawn on every hot and cold spheres and the background of the phantom: 12 background ROIs were drawn in the central slice and in slices ±10 and ±20 mm away. Hot sphere contrast recovery coefficient (CRC), cold sphere CRC and background variability were calculated according to the equations defined in NEMA NU2-2001 standard. The CRC and variability for the different sphere sizes, reconstruction method, region to background ratio in 2D/3D PET acquisition mode were calculated. CRC and variability was similar regardless of region to background ratio. Background variability of 3D was lower than that of 2D. However, CRC was similar in 2D/3D. The results suggest that background variability, not the recovery coefficient, can be improved by increasing count rate in order to enhance the lesion detectability in the oncology PET studies

[en] For the assessment of antithyroid effect of lithium carbonate, it was administered to the 17 hyperthyroid and 5 euthyroid patients, who visited the Seoul National University Hospital from Jan. to Aug., 1977. Thyroid function tests were performed just before the administration of Lithium carbonate, 2 weeks and 2 months after lithium treatment. The results were as follows; 1) In the 5 euthyroid patients, no significant changes in thyroid function tests were obtained before and after lithium treatment. 2) In the 17 hyperthyroid patients, the values of the T₃RIA were 370±121 ng/dl 2 weeks after lithium treatment as compared with 506±121 ng/dl before the administration, of which the mean percentage fall was 26.9%. T₃RU was varied from 56.8±8.0% to 47.3±8.1% (16.7% in mean percentage fall), T₄ was changed from 24.2±2.4 ug/dl to 22.0±4.2 ug/dl (9.1% in meanfall), and T₇, from 13.82±2.25 to 10.55±3.12 (23.7% in mean fall). 3) In the 5 hyperthyroid patients, serial thyroid function tests were performed 2 weeks and 2 months later. The mean percentage falls of T₃RIA were 36.6 and 61.3%, 2 weeks and 2 months after lithium treatment respectively. Those of T₃RU were 17.5 and 35.1%, those of T₄ were 20.4 and 44.0%, T₇, 35.0 and 60.7%. 4) Approximately 45-60% of mean fall in thyroid function tests were obtained within the second week. Normal thyroid function tests were observed in 2 among 17 patients within the second week, and 2 among 5 patients within the second month. 18 patients, however, became clinically euthyroid within the 4th week. 5) Single case of hypothyroidism was experienced, and 5 patients (29.4%) complained mild side effect. Lithium salts could be safely administered to hyperthyroid patients who are allergic to thioamides or iodine. Its use is indicated in cases of acute thyrotoxicosis in which it's necessary to reduce hormone levels very rapidly, and lithium-thioamides drug combination is a highly effective and safe means of initial routine control of hyperthyroidism.

[en] In the statistical probabilistic mapping, commonly, differences between two or more groups of subjects are statistically analyzed following spatial normalization. However, to our best knowledge, there is few study which performed the statistical mapping in the individual brain space rather than in the stereotaxic brain space, i.e., template space. Therefore, in the current study, a new method for mapping the statistical results in the template space onto individual brain space has been developed. Four young subjects with epilepsy and their age-matched thirty normal healthy subjects were recruited. Both FDG PET and T1 structural MRI was scanned in these groups. Statistical analysis on the decreased FDG metabolism in epilepsy was performed on the SPM with two sample t-test (p < 0.001, intensity threshold 100). To map the statistical results onto individual space, inverse deformation was performed as follows. With SPM deformation toolbox, DCT (discrete cosine transform) basis-encoded deformation fields between individual T1 images and T1 MNI template were obtained. Afterward, inverse of those fields, i.e., inverse deformation fields were obtained. Since both PET and T1 images have been already normalized in the same MNI space, inversely deformed results in PET is on the individual brain MRI space. By applying inverse deformation field on the statistical results of the PET, the statistical map of decreased metabolism in individual spaces were obtained. With statistical results in the template space, localization of decreased metabolism was in the inferior temporal lobe, which was slightly inferior to the hippocampus. The statistical results in the individual space were commonly located in the hippocampus, where the activation should be decreased according to a priori knowledge of neuroscience. With our newly developed statistical mapping on the individual spaces, the localization of the brain functional mapping became more appropriate in the sense of neuroscience

[en] The in vivo localization of a mixture of radioiodinated monoclonal antibody F(ab')₂ fragments of CEA and CA 19-9 was investigated in human colon cancer xenograft in nude mice. Scintigrams were taken 3 and 5 days after injection of ¹³¹I-labeled fragments in mice bearing transplanted tumor. Mice were killed afterward and the radioactivity in each tissue was analysed. Whole body scintigraphy clearly demonstrated selective localization of radioactivity over transplanted tumor without background subtraction with tumor:nontumor ratio of upto 3:1. Though absolute count in tumor of day 5 was lower than that of day 3, tumor to nontumor tissue ratio of day 5 was higher than that of day 3. Fragment of both monoclonal antibodies preferentially localized in tumor tissue compared with normal mouse IgG, as determined by differential tissue counting of radioactivity. The tumor to blood ratio for specific antibodies was much greater than that for normal IgG after injection. It is concluded that a radioactively labeled mixture of anti-CEA and anti-CA 19-9 antibodies is accumulated by colon carcinoma and that radioimmunodetection using gamma camera seemed to be useful for the detection of human tumor. (Author)

[en] Among noninvasive approaches for the evaluation of left ventricular performance, radionuclide ventriculography (RVG) has been shown to be of particular values. Phase analysis, recently introduced as more objective means for evaluating the temporal sequence of systolic ventricular wall motion than cine image of RVG comprises a pixel by pixel Fourier transformation of the time activity curve of a multiple gated acquisition equilibrium blood pool study. To examine the regional wall motion of ventricle in myocardial infarctions, we evaluated the phase image and histogram constructed for each ventricle by total phase angle range and full width of half maximum (FWHM), This study consisted of 7 normal subjects and 23 subjects with acute myocardial infarction. Contrast ventriculography and coronary angiography was performed in all patients with myocardial infarction. And we compared the result of phase analysis with cine image of RVG and examined the interrelationship between phase analysis and contrast ventriculography with coronary angiography. The results were as follow; 1) The total phase angle range and FWHM of LV phase histogram in myocardial infarction (86' and 32, respectively) were wider than those in normal control (38 and 18, respectively p<0.01). 2) RV phase angle range and FWHM in patients with right coronary artery (RCA) occlusion (79 and 37, respectively) were wider than those in normal control (39' and 18, respectively p< 0.001) and the patients without RCA occlusion (52' and 19, respectively p<0.01). 3) Phase analysis was more sensitive (95%) than cine image of RVG (70%) for the detection of regional wall motion abnormality of LV.