• Journal of Korea Foundry Society
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• v.31 no.5
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• pp.288-292
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• 2011

In order to complement the drawbacks of quartz crucible such as fragile-like break and melt-leakage through open slit nozzle, a new PFC system has been developed using a common graphite crucible and plugging system. The u melt is fed on to the rotating a roll through slit nozzle by self-gravity. The new equipment was designed and manufactured successfully. An effort for optimizing all related parameter has been made. Then using the optimized parameters about 10 meters u foil having very thin thickness, which meets the target thickness of 130 ${\mu}m$ and enough width more than 60 mm could be made. The thickness homogeneity set improved, due to the lower eddy flowing of the melt flow the self-gravity feeding system.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1449-1455
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• 2022

A radiotracer investigation was carried out in a Thermal Stratification Test Facility (TSTF) with objectives of investigating the dispersion and diffusion of radionuclide and effectiveness of the thermocline to minimize the radionuclide content in the hot water layer. Technetium-99m (^99mTc) as sodium pertechnetate was used as a radiotracer in the investigation. Qualitative analysis showed that a thermocline is formed within the TSTF and is effective in preventing the transport of radionuclide from bottom section to the top section of the facility. It was found that the radiotracer injected at the bottom of the pool took about 17.4 h to disperse from bottom to the top of the facility. The results of the investigation helped in understanding the effectiveness of hot water layer and thus to minimize the pool top radiation levels.

• Clinical and Experimental Reproductive Medicine
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• v.13 no.2
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• pp.181-185
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• 1986

To estimate the penile blood flow changes during artificial with erection intracorporeal papaverine injection, we injected 99 m Technitium-Human Serum Albumin via antecubital vein simultaneously and calculate the radioisotope activity of the penis using computerized Gamma Camera. We classified the results into 3 groups according to the transit time, erection persistent time and venous index in 67 impotence patients. We defined the arteriogenic impotence with the delayed transit time (more than 600 seconds) in 13 patients and venogenic with the shortened erection persistant time (less than 200 seconds) and decreased venous index (less than 0.8) in 11 patients. The rest of them (43 patients) were regarded as equivocal impotence, probably nonvasculogenic or psychogenic.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.19 no.1
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• pp.55-64
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• 1989

The purpose of this study was to clarify that scintigram was a more effective method than radiogram in the early detection of periapical lesion. Periapical lesions were produced artificially by the opening of the pulp chambers of the lower right 3rd and 4th premolars in 6 dogs. The serial bone scintigrams using 99m-Tc-MDP and periapical radiograms were taken weekly. The uptake counts of the 99-Tc-MDP in the experimental side were compared with those in the control side. The periapical radiograms were interpreted with the joint evaluation by three dental radiologists. The following results were obtained; 1. The radioactivity in the experimental side was increased at the Ist week except one animal in which the radioactivity was increased at the 2nd week. 2. It was observed that increasing amount of radioactivity per week was prominent from the 1st day of experiment to the Ist week, and the 3rd week to the 4th week. 3. The radiographic evidence of the periapical lesions was observed at the 3rd week and became more apparent at the 4th week. 4. Histologically, proliferation of blood vessels and infiltration of chronic inflammatory cells were observed at the 1st week and osteoblasts were found after the 3rd week.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.97-105
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• 1997

Mo-99(Molybdenum) is the only source of Tc-99m(Technetium) which is most frequently used in nuclear medical diagnostics and the demand is on the increase recently. Separation and refining of Mo-99 was investigated by adsorption and desorption on alumina. At pH=0.63, adsorption isotherm of Mo was fitted by Redlich ＆ Peterson equation using the adsorption experimental data. It was found that the pore diffusion model ($D_p=1.4{\times}10^{-6}cm^2/s, K_f/=0.4 cm/s$) agreed well with batch adsorption experimental data. RTDs(Residence Time Distributions ) were measured and axial dispersion coefficients were obtained in the fixed bed absorber according to the changes of the flow rate using 0.05% -NaCl. From the adsorption experimental data, it was shown that the behavior of breakthroughs depended on flow rate. Mo recovery yield was increased as adsorption flow rate was increased and desorption flow rate was decreased.

• Journal of Biomedical Engineering Research
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• v.20 no.6
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• pp.515-521
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• 1999

Scintillator crystal is an important part and detcrmines performance characteristics of the gamma camera. We investigated the offects of scintillation crystal surface treatment on gamma camera imaging. Nal(TI) and Csl(Tl) scintillators. 20 mm diameter and 10 mm thickness, applied with two different surface treatments, white and black reflcetors, were applied to Nal(Tl) and Csl(Ti). The optical properties of generated scintillation light were evaluated by Monte Carlo simulation method and by actual measurement using a position sensitive photomultiplier tube (PSPMT). We measured sensitivity, energy resolution and spatial resolution of gamma camera with the various scintillators coupled to a PSPMT. In the simulation. Nal(Tl)-white prosented the best sensitivity. In the measurements, the sensitivities and the intrinsic spatial resolutions of Nal(Tl)-white, Nal(Tl)-black. CsI(Tl)-white, CsI(Tl)-black were 2920, 2322, 1754, 1401 cps/$\mu$ci and 5.2, 4.5, 7.0, 6.3 mm FWHM. respectively. Their intrinsic energy resolutions were mesured 12.5, 23.5, 20.5, 33.3% FWHM at 140 keV Tc-99m. In this study, we investigated the offects of a side surface treatment of the scintillator on the gamma camera imaging. Simulation and measurement prescnted similat trends. Based on the results, we concluded that the surface of th NaI(Tl)seintillator must be treated by absorptive materials in order to develop the gamma camera having good spatial resolution.

• The Korean Journal of Nuclear Medicine
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• v.15 no.2
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• pp.1-9
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• 1981

Bone scans with $^{99m}Tc-MDP$ (methylene diphosphonate) were obtained and analysed in 574 patients with biopsy-proven malignancy, who visited Seoul National University Hospital from April, 1979 to June, 1931. Clinical staging was done in all patients without bone scan information and compared with bone scan to determine the predictive value of bone scanning. 1. Primary site of the maligancies were lung in 152, breast in 97, stomach in 43, colon in 15, esophagus in 9, liver and pancreas in 11, kidney in 14, bladder in 27, prostate in 22, thyroid in 20, skin in 11, bone in 9, head and neck in 36, ovary and uterus in 17, hematopoietic and lymphoretic ular system in 33, nervous system in 10, and others in 9 cases. Primary site was not defined in 39 cases. 2. Bone scans were positive in 186 cases (32.4%), which, included 48 cases (31.6%) of lung cancer, 27 cases (27.8%) of breast cancer, 12 cases(28%) of stomach cancer, 6 cases(40%) of colon cancer, 6 cases(43%) of kidney tumor, 4 cases(15%) of bladder cancer, 14 cases(64%) of prostate cancer, 3 cases(15%) of thyroid cancer and 66 other cases. 3. Bone scans were suspicious in 64 cases (11.2%) which included 29 cases (19.1%) of lung cancer, 10 cases (10.3%) of breast cancer, 4 cases (9.3%) of stomach cancer, one case (7%) of colon cancer, 3 cases(11%) of bladder cancer, 2 cases(10%) of thyroid cancer and 15 other cases. 4. Out of 121 cases with early stage of malignancy (which included 20 cases of lung cancer in stage I, II, 38 cases of breast cancer, 13 cases of stomach cancer, 8 cases of kidney tumor, 14 cases of thyroid cancer in stage $I{\sim}III$, and 6 cases of colon cancer, 14 cases of bladder cancer, 8 cases of prostate cancer in stage $A{\sim}C$, bone scans were positive in 5 cases (4.1%) which included 3 cases of lung cancer one case of breast cancer and one case of prostate cancer, and considered as further advanced stage. Out of 121 cases with early stage of malgnancy, bone scans were suspicious in 21 cases (17.4%) which inlcuded 9 cases of lung cancer, 4 cases of breast cancer, 2 cases of stomach cancer, one case of colon cancer, 3 cases of bladder cancer, and 2 cases of thyroid cancer. From these results, we concluded bone scan was useful in detecting bone metastasis in patients of early stage of malignancy, determining prognosis and establishing therapentic plan.

• Clinical and Experimental Pediatrics
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• v.49 no.6
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• pp.648-652
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• 2006

Objective : $^{99m}Tc$-dimercaptosuccinic acid(DMSA) scan is considered to be the most sensitive examination for detection of renal scars. However, because of its high radiation exposure to the kidney and its limited usefulness for patients with low grade vesicoureteral reflux(VUR), some authors have suggested that DMSA scans should be reserved primarily for children with VUR grade 3 and above. The aim of this study was to reevaluate the necessity of DMSA scans as a screening test in infants without reflux or with low grade reflux. Methods : In this retrospective study, 189 infants(mean age : 6.2 months) diagnosed as UTI were enrolled. Voiding cystourethrogram(VCUG), DMSA scan and renal ultrasonography were performed within 1 month of UTI. VUR grade was classified into three subgroups; low grade(grade 1-2), moderate grade(grade 3), and high grade(grade 4-5), respectively. Results : Renal defects were present in 67 of 189 infants, and 82 of the 378 renal units. The incidence of renal defects was significantly correlated with VUR grade(P<0.01); 28 percent without reflux, 38 percent with low grade, 53 percent with moderate grade, 100 percent with high grade, respectively. However, there was no significant differences in incidence of renal defects between the low grade and moderate grade group. Conclusion : In this study, renal defects were found in quite high percentages; 28 percent patients without reflux and 38 percent patients with low grade VUR, respectively. Moreover, there was no significant difference in the incidence of renal defects between the low grade and moderate grade groups. Therefore, DMSA scan should be performed for infants with UTI as a screening test regardless of the presence of VUR.

• Journal of Pharmaceutical Investigation
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• v.33 no.2
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• pp.145-149
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• 2003

Manufacturing facilities of the pharmaceuticals must meet certain level of the cleanness required so that foreign substances such as dust, moisture, heat, microorganism, or virus do not contaminate the product. In case of radiopharmaceuticals for medical treatment and diagnosis, not only should the operators and environment be protected from radiation but also need to be isolated from the foreign contaminant. Therefore, manufacturing facilities for radiopharmaceuticals must satisfy the design standards of both hot cell and clean room which are specified by GMP. However, standards of maintaining negative pressure for preventing spread of radioactive contaminant in isolated facilities conflict with the standards of maintaining positive pressure for keeping cleanness. To solve this problem, air pressure of hot cell was designed lower than in the adjacent area to meet standards of the radiation safety. To keep higher cleanness in certain part of the hot cell for filling, minimal relative positive pressure allows. In order to effectively maintain the cleanness that is required for production of Tc-99m generator, which takes 70% of whole demand of radiopharmaceuticals, the rooms placed in each side of production room are used as a buffer area and three lead hot cells are installed in production room. In this research, we established the appropriate engineered design concept for Tc-99m generator manufacturing facility, which satisfies both GMP cleanness standard for preventing particles, bacteria, other contaminants and the regulations of radiation safety for supervising and controlling the amount of radiation exposure and exhausted radioactivity. And the concept of multi-barrier buffer zones is introduced to apply negative air pressure for hot cell with first priority and to continue relative positive air pressure for clean room.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.73-77
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• 2010

Purpose: The nuclear medicine technology has been changed. The hard ware is developed so much. Also the soft ware performs a meritorious deed for the development of nuclear medicine technology. We could use the automated region of interest (ROI) instead of manual ROI. We want to know that what difference of quantitative analysis is there between automated ROI and manual ROI Materials and Methods: There are three experimental to make results. The first is what comparing the renal automated ROI and manual ROI. The second is that we compared three threshold ROI that size is difference each others with visible decision. The third is that we compared full, half, quarter automated background, and survey relative function. Results: Although the first has statistically not significant difference, the second and third have significant difference. Threshold, setting smaller threshold then renal outline or bigger, has statistically significant difference (p<0.01). The third is performed with the first experimental. Full background has significant difference, comparing each three type background (p<0.05). Conclusion: The results that there is not significant difference between automated ROI and manual ROI will increase objectivity and operator's convenience. We could know that smaller threshold then renal out line has significant difference in the second experimental. And the third experimental has results because of a increased background nearby live and spleen.