• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.65-69
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• 1986

An asymmetry in dose profile of a $^{60}Co$ teletherapy unit was found by means of water-phantom measurement. The reason of that trouble was confirmed to be the abnormal 'ON' position of the source, which is resulted from the high friction between contiguous surfaces of the spring for driving the source to 'OFF' position. Lubrication in the spring improved the mobility a little, but was not a radical repair. The radical repair was to replace the old spring by new one. Periodic maintenance for source driving system and periodic measurement of field symmetry are required for prevention of abnormal 'ON' position of $^{60}Co$ source.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.137-147
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• 1988

This study was designed to investigate the effects of irradiation on the salivary ductal cells, especially on the intercalated ductal cells of the rat parotid glands. For this study, 36 Sprague-Dawley strain rats were irradiated on the head and neck region with absorbed dose of 15Gy by Co-60 teletherapy unit, Picker's model 4M60. The conditions irradiated were that field size, SSD, dose rate and depth were 12×5㎝m, 50㎝, 222 Gy/min. and 1㎝. respectively. The experimental animals were sacrificed 1, 2, 3, 6, 12 hours and 1, 3, 7 days after the irradiation and the changes of the irradiated intercalated duct cells of the parotid glands were examined under the light and electron microscope. The results were as follows: 1. Under the light and electron microscope, the nucleus, mitochondria and secretory granules showed severe changes in the early stage after irradiation and the most severe cellular de- generations were observed 2 hours after irradiation, but the repair processes began from 6 hours after irradiation. 2. Under the electron microscope, loss of the nuclear membranes, derrangement of the chromosomes, swelling and destruction of the secretory granules, and widening of the intercellular spaces were observed after irradiation. 3. Under the light microscope, atrophy and irregular proliferation of the ductal cells, cuboidal metaplasia, hyperchromatism, and the construction or obstruction of the lumen were observed after irradiation.

• Journal of the Korean Society of Costume
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• v.59 no.2
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• pp.143-153
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• 2009

The purpose of this study is to provide color information in order to planning and merchandising in china fashion through the color of Beijing opera. In objective study, we collect total 302 Beijing opera images. The collecting method of source data is to extract digital color data by color picker. We transform RGB color data to H V/C, CIE L*a*b and analyze the attributes of color and tone, three-dimensional analysis. The results of this study are as follows : 1. The color distrbution of Beijing opera is R(26.9%)>YR(18.2%)>PB(11.6%)>Y(9.6%). Traditional preference color, red is most popular color as 26.7%:, the practice of vivid tone red is numerous. 2. The tone distribution of Beijing opera costume is P(16%)>It(13.9%)>d(11%)>5(9.6%)>4kg (8.2%)>b(7.1%:). The value o# Beijing opera costume distribute medium and medium-high and the chroma of those distributes low. 3. High chroma yellow is restrictive color as the symbol of emperor in china but medium-low chroma yellow is very frequently used. 4. Blue is often used in china costume. Especially in Beijing opera costume blue is symbol of bravery, dignity, cruel character 5. White in Beijing opera costume is much used for symbol of righteous loyalist. Black is less used than white in Beijing opera costume and black is authority color for symbol of the prime minister.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.16 no.1
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• pp.49-58
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• 1986

This study was designed to investigate the irradiation effects on the rat parotid gland, applied to the head and neck region. For this experiment, twenty-four rats, feeded under the even condition, were used as experimental animals. Twenty rats were used for experimental group and the rest were assigned to the control group. The experimental group was singly irradiated with 10Gray through Cobalt-60 radiotherapy device, Picker model 4M 60 (Field size; l2×5㎝, SSD; 50㎝, Depth; 1㎝). The experimental animals of both group were sacrificed each four animals in 2 days, 1week, 2weeks, 3weeks and 4weeks after irradiation. The specimens were examined through the light microscope using the H-E stain and H stain by routin procedure. The other specimens were observed under the fluorescence microscope using the B-O dichroic mirror and Y455 barrier filter after PA-ACH stain. 1. The results of this study were obtained as follows, The parotid acini were severely degenerated and the intraacinar spaces were widened. Within the acini, retained secretory granules and increased fibrosis were observed. Also the shape and the size of the acini showed very irregular atrophic degenerations. 2. The nuclei showed severe pyknosis, displacement and irregular aggregated appearance. 3. The tissue changes of the parotid acini were initiated after 2 days of irradiation and most severely appeared at the second week of irradiation, but almost returned to normal. 4. The salivary ducts of the parotid gland were severely atrophied, discontinued but initiated to regenerated after 3 weeks of irradiation.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.7-20
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• 1987

The author studied the acute reaction of cobalt-60 irradiation to buccal mucosa in rats and difference of the effects of single versus fractionated exposure. 195 Sprague Dowley strain rats, weighing about 120gm, were used in this experiment. 3 rats served as controls and the remaining 192 rats were divided into six groups of 32 rats each. Experimental group Ⅰ, Ⅱ, Ⅲ were received a single dose of 15Gy, 16.5Gy, 18Gy and group Ⅳ, Ⅴ, Ⅵ were received two equal sized fractionated dose of 9Gy, 9.75Gy, 10.5Gy at 4 hour intervals, respectively. The experimental groups were irradiated with cobalt-60 teletherapy unit, Picker model 4M 60 (Field size, 12x5 cm, SSD, 50㎝, Dose rate, 222cGy/min, Depth, 1㎝). The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and the changes of the irradiated buccal mucosa were observed by electron and light microscopy. The results were as follows: 1. A single exposure was more damaging than fractionated exposure, and as the radiation dose increased, the changes of cell organelles became faster, but the healing of radiation-induced damage in fractionated exposure was faster than in single exposure. 2. The radiation-induced changes of the basal cells were the most prominent in 18Gy-single exposure group, and the least in 18Gy-fractionated exposure group. 3. Electron-microscopically, there appeared nuclear changes, swelling of mitochondria and rough endoplasmic reticulum, decrease of free ribosome, presence of vesicles, widening of intercellular space, and loss of basal lamina. The early remarkable changes were partly loss of nuclear membrane and swelling of mitochondria. 4. Light-microscopically, derangement and pyknosis of basal cells, hydropic changes of spinous cells, enlargement of granular cells, indistinctness of basement membrane, and proliferation of epithelium were observed.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.117-128
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• 2003

Thallium-201 scintigraphy is used to discriminate the malignant bone tumor from the benign by qualitatively and quantitatively, and to predict the response of preoperative chemotherapy in osteosarcoma, by comparing the changes of thallium uptake ratio after chemotherapy to the tumor necrosis ratio. Thallium-201 scintigraphy scan should be done prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator is usually used for scanning. The patient is injected with 2-3mCi of Tl-201 and the early phase is checked in 30 minutes and delayed phase in 3 hours. The scan images are visually evaluated by a blinded nuclear medicine physician. We could evaluate true positive, true negative, false positive and false negative by the comparison of results with those of biopsy, and calculate positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%). For the quantitative analysis of thallium uptake, we drew the region of interest on the tumor side and contralateral normal side as mirror image, and calculated the uptake ratio with dividing the amount of gamma count in tumor side by normal side. We could calculate the percent changes of thallium uptake ratio in early and delayed phase, and compare them to the ratio of tumor necrosis. Thallium-201 scintigraphy proved as useful imaging study to discriminate malignant bone tumor from benign, but had exception in giant cell tumor and low grade malignant bone tumors. We can use T1-201 scan to differentiate the benign from the malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.177-187
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• 1988

This study was designed to investigate the effects of split irradiation on the salivary ductal cells, especially on the intercalated cells of the rat parotid glands. For this study, 24 Sprague-Dawley strain rats were irradiated on the head and neck region with two equal split doses of 9Gy for a 4 hours interval by Co-60 teletherapy unit, Picker's model 4M 60. The conditions of irradiation were that field size, dose rate, SSD and depth were 12×5㎝, 222 cGy/min, 50㎝ and 1㎝, respectively. The experimental animals were sacrificed 1. 2, 3, 6, 12, hours and 1, 3, 7, days after the irradiation and the changes of the irradiated intercalated cells of the parotid glands were examined under light and electron microscope. The results were as follows: 1. By the split irradiation, the degenerative changes of intercalated cells of the parotid glands appeared at 3 hours after irradiation and the most severe cellular degeneration observed at 6 hours after irradiation. The repair processes began from 12 hours after irradiation and have matured progressively. 2. Under electron microscope, loss of nuclear membrane, microvilli and secretory granules, derrangement of chromosomes, degeneration of cytoplasm, atrophy or reduction of intracytoplasmic organelles were observed in the intercalated ductal cells after split irradiation. 3. Under light microscope, derrangement of ductal cells, widening of cytoplasms and nuclei, hyperchromatism and proliferation of ductal cells were observed in intercalated ducts after split irradiation.

• Progress in Medical Physics
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• v.7 no.2
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• pp.3-17
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• 1996

Dose compensators have been widely used in radiotherapy fields. But, few reliable verification methods have been reported. We have developed the verification method for the evaluation of the effect of dose compensator using exit beam dose profile. The exit beam dose profiles were measured with and without dose compensator. For this purpose X-Omat V films and lead screened cassettes are used and dose distibutions are compared. Phantom data are collected using CT simulator(Picker, AcQ Sim) and compensator information can be obtained from Render Plan 3-D planning System. Aluminum Compensators are generated by computer controlled milling machine. The real dose distribution in the phantom and the exit beam dose profile can be obtained simultaneously with the films in the phantom and the opposite site of the beam. Dose compensations effects for oblique beam, parallel opposing beam and inhomogeneous human phantom can be obtained using above tools. And we could simate those effects with exit beam dose profile using the method that we have developed in this study.

• Journal of radiological science and technology
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• v.5 no.1
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• pp.35-43
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• 1982

The authors surveyed the cassettes in 10 general hospitals and compared in experimentation on performances of 6 kinds of cassettes manufactured with several materials in order to discover the present condition and performance of the cassettes being used at present. And the authors got the following results. 1. In distribution of the cassettes in use, Okamoto's(Japan), Picker's and Titan's(U.S.A.) were more than others classified by the manufacture. The rate of using high speed was 72.0%, par speed 28.0% classified by types of intensifying screens in the cassettes and the rate of the year in use for $4{\sim}5$ years was 40.0%, $6{\sim}7$ years 24.0% classified by the years in use. 2. The results of the screen-film contact test were that tile ordinary was 42.7%, the good 36.0%, and the poor 21.3%. 3. The results of the test for light leakage were that fogged area appeared on 1 side or more in 84.0% films. 4. In Aluminum equivalents of front plate, the cassettes with a front plate consisting of carbon fiber were fewest, and the ones of bakelite and aluminum were fewer in order 5. In compared results of the exposure dosage for same density of the films, the exposure of the cassettes used carbon fiber for the material on the front plate was smallest and bakelite, auminum was smaller in order.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.219-225
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• 2014

An automatic combination and assembly system for phone-camera lens modules was developed. The system enables the assembly of the relative orientation of the individual lenses making up the lens module. Conventional assembly systems assemble a lens module from eight assembly units. The developed system reduces this number to half by combining each lens and a spacer into a single assembly unit. Also, the number of transfer stages for sequential assembly is minimized without increasing the assembly time. Therefore, high productivity and a footprint that is only about 25 % of that of a conventional assembly system can be realized. The system features a modular design to allow it to cope with rapid changes in the market. Only a few components, such as the picker and guide, need to be replaced for changing to a new assembly model.