• Journal of Biomedical Engineering Research
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• v.9 no.1
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• pp.61-66
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• 1988

Because the amount of radiation emerging from the thorax behind the lungs is often literally thousands of times that exiting behind the mediastinum, the dynamic range of X-ray chest image is very large. In order to solve the dynamic range problem, we propose a signal adaptive algorithm which enhances the local contrast and contracts the enhancement of quantum noise by local mean/valiance estimator.

• Journal of radiological science and technology
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• v.17 no.2
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• pp.29-35
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• 1994

Tomographic examination requires several times of exposure usually, therefore, reduction of radiation dose per exposure without loss of image quality proves of great benefit to patient. We compared the exposure doses under the following experimental conditions, A and B. A is the combination of SRO 380(rare earth screen) and SRH(high contrast film) with additional Cu filters or without. B is the widely used combination which is BH-III and Cronex-4 without additional filter. As a result, comparing with the condition B, the condition A with additional filter of Cu 0.15 mm + Al 0.7 mm, Cu 0.4 mm+ Al 0.4 mm and Cu 0.8 mm showed better Image quality and lower surface dose, 44 %, 31 % and 24 % of the condition B, respectively.

• Journal of radiological science and technology
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• v.22 no.1
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• pp.13-20
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• 1999

This study is to calculate the exposed radiation dose using Bit method, NDD calculation method and monogram method without dosimeter. In addition, we can calculate the radiation dose from x-ray film density as a film badge. The authors examined the entrance skin dose from $2{\sim}3$ intercostal chest x-ray film density. We also studied the relationship between film density and equivalent dose in the each screen film system under the different radiation quality and the poor geometry condition of grid ratio. As results, we established the deductive method to define the entrance skindose from chest x-ray film density. The error range was found in the range $-13%{\sim}+l7%$ for between deductive entrance skindose and the $2{\sim}3$ intercostal chest x-ray film density to actual detective radiation dose with dosimeter.

• Journal of radiological science and technology
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• v.15 no.2
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• pp.31-36
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• 1992

Grids can improve the diagnostic quality of chest radiography by trapping the greater part of scattered radiation thus providing more detailed. chest radiographic images. It is most effective mathod of reduce the scatter ratio but must increase the expour factor. The benefit of use of grid is improve the contrast and the loss is increase of patient dose. In chest radiography especially hard quality high voltage radiography it will have to be considered to select the optimum grid with view point of benefit and loss. In this experiment, author got some result of characteristics about 4 different grids with film method. 1. There was no difference the scatter ratio in case of no grid and the scatter ratio was about 60%. 2. 16 : 1 grid was excellent of scatter reduction factor in high voltage chest radiography, next was 10 : 1, CROSS, MICRO FINE grid have low scatter reduction rate compare to 16:1, 10:1 grid. 3. The bucky factor of CROSS grid in accordance of kVp was find out the highest in 4 grids, on the contraly 10 : 1 grid was profitable to the exposure does. 4. With careful consideration in the point of scatter reducion rate and bucky factor, author suggest the 10 : 1 linear grid on the use of chest radiography in $80{\sim}120\;kVp$, 16 : 1 grid in $120{\sim}140\;kVp$.

• Journal of radiological science and technology
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• v.15 no.1
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• pp.79-87
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• 1992

It is a matter of common knowledge that madical radiation is most accented for of radiation is doses applied to the whole of people, and of them the radation dose by radiography diagnosis is mainly prevalent. In applying X-rays to a certain man for radiography diagnosis a radiologyist will have to have an absolute sense of mission concerning the reduction and prevention of the patient's radiation dose as the radiologyist obligation. Accordingly, the radiography conditions of the patient's chest employed 197 medical facilites were surveyed and skin dose was computated by the IPH Bit system and examined. As a result, it was shown that the average skin dose was $288\;{\mu}Sv$, its minimum value was $1600\;{\mu}Sv$, which was over 32 times its minimum value. This shows that the appropriate radiography method has not been applied at applying X-ray to the patient. It comes from the performance of X-ray equipment, the choice of auxiliary equipment materials etc. But the most important thing is to master the appropriate radiography condition, and therefore this point will have to be kept in mind.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.59-69
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• 1979

For the clearer visualization of the lung apices in the routine chest P-A view, we have analysed the films at the different positions and different directions of the central X-ray beams. The brief results are as the follows. 1. Best visualization of the lung apices are made with the following position of the patient and central ray. Central ray is directed to the median sagittal plane at the level of the 5th thoracic vertebra with the palms of the hands placing at the greater trochanteric area of the both femurs. 2. The position of the sterno-clavicular joint shows no alteration between the radiographs with the central beam to the film center and to the 5th thoracic vertebra, and position of the hands at the greater trochanters or iliac crests. 3. No relationship exists between the center of the film and the position of the hand. The central beam is projected more inferiorly when the beam is centered to the film center than to the 5th thoracic vertebra. 4. The scapulae are rotated sufficiently anteriorly and more inferiorly, with placing the palms at the greater trochanters, directing central ray to the 5th thoracic vertebra, and with close contact the lung apices to the cassette.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.31-35
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• 1979

A thorax is consisted of a heart, great vesseles, lungs, ribs, sternum and thoracic spine etc. The quality of chest radiogram is very important in order to find out abnormality in the lung field. The image has two major characteristics; density and contrast which directly influence the diagnostic quality of the roentgenogram. It is very hard to make excellent film image in the lung field because of overlapping bones and other soft tissues. To take a good radiogram of lung field, we studied the condition of chest P-A projection in adult and obtained results as follows: 1. The average chest radiographic condition is resulted as 62KVP, 16 mAs in hospitals around Kyung Ki-Do, Korea, 2. The density of the chest 20cm in thickness, is equal to the water phantom 8cm in thickness. 3. The best quality of chest radiogram is achieved in the condition of the lung field at 100KVP, 9.6mAs by use of Grid 8:1.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.23-29
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• 1979

Roentgenographic film has to be handled with greatest care during removal from the packing, loading of the cassettes and loading of the hanger. In the case of prior to or after exposed film is handled with mechanical pressure in darkroom, the most common phenomena are desensitization or sensitization on roentgenographic film. In order to observe these defect occurring on, it, the author studied on change of the densities where the mechanical pressure reached to the roentgenographic film. 1. The optimal minimum and maximum densities in routine chest x-ray film are from 0.25 to 1.47 2. The dependence of the desensitization occurring on film upon the bent degree of film is in the portion to bent degree over $10^{\circ}$ 3. Appearances of the desensitization on film by the curved degree of film is inverse proportion to it's degree below intervals of 3cm. 4. The more unexposed film is bent with nail tip and is pressured with palm, the more desensitization it was appeared upon film size and pressure weight. 5. The most serious area of desensitization produced by many types of mechanical pressure is in the portion of lung apex and outside lung fields. 6. The tendency of desensitization due to mechanical pressure on unexposed film is more serious than sensitization on exposed film in the view of radiologic diagnosis.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.15-22
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• 1979

Author made a experiment on the exposure dose with various intensifying screens in taking chest roentgenogram and obtained the results as follows; 1. Special speed type was the most sensitive intensifying screen, the r(gamma) value of this screen was distributed from 2.6 to 2.9. 2. The resolution activity of intensifying screen was inversely proportional to its sensitivity. If, the sensitivity and detail of the fine detail speed type intensifying screen at 100 KV were 100, those of the special speed type were 549 and 54.44 respectively. 3. If the exposure dose of the fine detail type intensifying screen was 1.0 at 60 KV, that of the special speed type intensifying screen was 0.1 at 80KV, and the skin dose of patient was as follows; it was 64.8 mRad at 60KV in mid speed type, 8.1 mRad at 80KV in super high speed type, and 7.2 mRad at 80KV in special speed type intensifying screen respectively.

• Journal of Chest Surgery
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• v.29 no.1
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• pp.115-119
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• 1996

Malignant fibrous histiocytoma after radiation therapy is very rare and its prognosis is poor. A 52-year-old male patient was admitted due to painful mass at the sternal area which developed 6 months ago. The patient had a history of radiation therapy for esophageal cancer 5 years ago. The incisional biopy disclosed sternal sarcoma. In spite of 5 cycles of chemotherapy, the m ss progressively enlarged, and an operation was performed. Total sternectomy with overlying skin and postal cartilage was performed and reconstruction was carried out with autologous rib bone graft, bilateral pectoralis klajor muscle flap and skin graft. The microscopic examination was consistent with malignant fibrous histiocytoma. The postoperative course was uneventful and the patient was discharged on postoperative 36 day.