• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.503-508
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• 2019

In short a binary value according to a change in the tube voltage by using one of VOLUME AXIAL MODE of scanning techniques of chest CT image quality evaluation in order to obtain high image and to present the appropriate tube voltage. CT instruments were GE Revolution (GE Healthcare, Wisconsin USA) model and Phantom used Pediatric Whole Body Phantom PBU-70. The test method was examined in Volume Axial mode using the pediatric protocol used in the Y university hospital of mass-produced material. The tube voltage was set to 70kvp, 80kvp, 100kvp, and mAs was set to smart mA-ODM. The mean SNR difference of the heart was $-4.53{\pm}0.26$ at 70 kvp, $-3.34{\pm}0.18$ at 80 kvp, $-1.87{\pm}0.15$ at 100 kvp, and SNR at 70 kvp was about -2.66 higher than 100 kvp and statistically significant (p<0.05) In the Lung SNR mean difference analysis, $-78.20{\pm}4.16$ at 70 kvp, $-79.10{\pm}4.39$ at 80 kvp, $-77.43{\pm}4.72$ at 100 kvp, and SNR at 70 kvp at about -0.77 higher than 100 kvp were statistically significant. (p<0.05). Lung CNR mean difference was $73.67{\pm}3.95$ at 70 kvp, $75.76{\pm}4.25$ at 80 kvp, $75.57{\pm}4.62$ at 100 kvp and 20.9 CNR at 80 kvp higher than 70 kvp and statistically significant (p<0.05) At 100 kvp of tube voltage, the SNR was close to 1 while maintaining the quality of the heart image when 70 kvp and 80 kvp were compared. However, there is no difference in SNR between 70 kvp and 80 kvp, and 70 kvp can be used to reduce the radiation dose. On the other and, CNR showed an approximate value of 1 at 70 kvp. There is no difference between 80 kvp and 100 kvp. Therefore, 80 kvp can reduce the radiation dose by pediatric chest CT. In addition, it is possible to perform a scan with a short scan time of 0.3 seconds in the volume axial mode test, which is useful for pediatric patients who need to move or relax.

• Journal of Microbiology
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• v.45 no.1
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• pp.58-63
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• 2007

In this study, the relative synonymous codon and amino acid usage biases of the broad-host range phage, KVP40, were investigated in an attempt to understand the structure and function of its proteins/protein-coding genes, as well as the role of its tRNAs. Synonymous codons in KVP40 were determined to be AT-rich at the third codon positions, and their variations are dictated principally by both mutational bias and translational selection. Further analysis revealed that the RSCU of KVP40 is distinct from that of its Vibrio hosts, V. cholerae and V. parahaemolyticus. Interestingly, the expression of the putative highly expressed genes of KVP40 appear to be preferentially influenced by the abundant host tRNA species, whereas the tRNAs expressed by KVP40 may be required for the efficient synthesis of all its proteins in a diverse array of hosts. The data generated in this study also revealed that KVP40 proteins are rich in low molecular weight amino acid residues, and that these variations are influenced primarily by hydropathy, mean molecular weight, aromaticity, and cysteine content.

• Korean Journal of Digital Imaging in Medicine
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• v.4 no.1
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• pp.72-79
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• 1998

With this experiment we have conclusion as follows. $\cdot$ Total FCR-9501 are 8 units. $\cdot$ All hospitals under study are conducting the high kvp radiographing with 115-120kvp and 4$\sim$10mAs. $\cdot$ The mean value of the chest exposure was 0.524$\sim$0.301mGy. $\cdot$ The percentage of the absorber finding from phantom was more the 85% with a range of 100$\sim$136 kvp. $\cdot$ The mean dose from phantom was 0.990mGy with 124 kvp and 16 mAs. $\cdot$ There is no difference in the amount of information due to the change of kvp and mAs, but some coarseness of images can be seen in the magnified images. $\cdot$ The resolving power was about 1.5/mm. $\cdot$ The increase and decrease of 10$\sim$30 kvp from common kvp has not influenced on the amount of information. $\cdot$ The exposure could be reduced by 0.170$\sim$0.570mGy.

• Journal of radiological science and technology
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• v.7 no.1
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• pp.53-66
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• 1984

The quality of continuous x-ray beam depends upon the half value layer which varies according to the geometric conditions, the filtration thickness, and the amount of accelerated voltage (KVP). Experiments were conducted on the amount of electric energy that was changed to x-ray energy, and on the relationship between KVp and the intensity of x-rays. The results were as follows: 1. The amount of x-rays were not equal under the condition of the same exposure factor. 2. The intensity of x-rays was attenuated by an exponential function the geometric conditions were "good" and it was not when they were "poor". 3. The thicker the total filtration substance was and the higher the KVp was, the bigger the amount of x-ray energy was. 4. The homogeneity of medium energy x-ray was the best, when the total filtration substance was 3.9mm A1. 5. The mean energy of continuous x-ray was about 45% of KVp.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.85-88
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• 1979

When X-radiation passes through the human body; some is transmitted some is truly absorbed, and some is scattered. In diagnostic radiography, scattered radiation can reach the film if no protective measures are taken. This scattered ray increased density which not necessary for image formation. We studied about absorbtion, scattered ray and the way of get rid of scatter ray according to the x-ray tube kilovoltage and obtained results as follow; 1. Absorbtion ray increased proportion to KVP. 2. Scattered ray increased at high KVP and thick object. 3. Secondary radiation of the primary increased at high KVP and thick object. 4. Remove .ate of scattered ray decreased at thick object and increase at low KVP make use of 6:1 grid ratio

• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.146-151
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• 2001

This study was carried out to find if the X-irradiation being used for clinical diagnosis during pregnancy would affect fetal development and cause fetal malformation in rats or not. To determine the dose and irradiation frequency of X-irradiation and gestation period by which fetal development would be affected when irradiated during pregnancy, seventy-two Sprague Dawley female rats (8 weeks old) were used for the experiment and grouped into three according to different gestation period of 5-8 days, and 6-12 days of gestation. Experimental rats were irradiated on the daily irradiation conditions of 40, 60, 80 kvp(kilo volt peak), 150 mA(milliampere), 0.25 sec and 4 times/day for both 5-8 days and 10-13 days of gestation, and 100 kvp, 100 mA, 2 min. and 4 times/day for 6-12 days of gestation. Rats were put in a small dark box when irradiated, which animals were sacrificed on the 20th day of gestation and mean litter size, fetal body weight, fetal crown-rump length(CRL) were investigated along with pathological findings. 1. Litter size were significantly decreased in the rats which were irradiated by both 60 and 80 kvp during 5 to 8 days of gestation and by 100 kvp during 6-12 days of gestation compared to those from the control rats(p<0.05) 2. Fetal body weight was significantly decreased in the fetus from the rats which were irradiated by both 60-80 kvp during 5-8 days of gestation and by 100 kvp during 6-12 days of gestation compared to those from the control rats(p<0.05). 3. There was no significant difference of fetal crown-rump length between all the experimental rats and the controls. 4. Fetal absorption, fetal death, and fetal malformation were not observed in the fetus form the rats irradiated by 40-80 kvp during 5-8 and 10-13 days of gestation, however, the pathological findings were found in those from the rats irradiated by 100 kvp during 6-12 days of gestation. 5. The harmful effect of x-irradiation on fetal development was estimated to occur when irradiated during 5-8 days of gestation. These results indicated that even X-irradiation for clinical diagnosis could affect fetal development in the early embryonic stage and when the fetus were exposed to frequent and prolonged x-irradiation with over dose.

• Journal of radiological science and technology
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• v.7 no.1
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• pp.79-84
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• 1984

• Journal of radiological science and technology
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• v.10 no.1
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• pp.13-23
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• 1987

Author has studied for finding the method of decreasing the radiation dose and increasing diagnostic range in chest X-ray radiography. The study for the added filter thickness from half value layer to 1/8 value layer by decreasing curve and research for the exposure factors, decreasing ratio of radiation dose, ratio of scatter ray and image quality in chest X-ray radiography. The results were as follows: 1. By using the rare earth intensifying screen system at 120 Kvp, the sensitivity is increased by times and the exposure ratio is decreased 0.22 by comparison with the $CaWO_{4}$ intensifying screen system at 80 Kvp. 2. By using Al added filter of 1/8 value layer, the scatter ray is increased more than no filter, But the scatter ray is decreased more in $G_{4}/RxOG$ intensifying system than in LT-II/Rx intensifying system. 3. At 120 Kvp, the image quality value of $G_{4}/RxOG$ system is increased more than LT-II/Rx system compared with slight decreasing image quality value at 80 Kvp. Concluded that by using the added filter could decrease the radiation dose by 1/3 and obtain effective image quality with the added filter at high voltage hard exposure.

• Progress in Medical Physics
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• v.17 no.2
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• pp.105-113
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• 2006

This study peformed to confirm the corrected dose In different electron density materials using the superposition/FFT convolution method in radiotherapy Planning system. The experiments of the $K_2HPO_4$ diluted solution for bone substitute, Cork for lung and n-Glucose for soft tissue are very close to effective atomic number of tissue materials. The image data acquisited from the 110 KVp and 130 KVp CT scanner (Siemes, Singo emotions). The electron density was derived from the CT number (H) and adapted to planning system (Xio, CMS) for heterogeneity correction. The heterogeneity tissue phantom used for measurement dose comparison to that of delivered computer planning system. In the results, this investigations showed the CT number is highly affected in photoelectric effect in high Z materials. The electron density in a given energy spectrum showed the relation of first order as a function of H in soft tissue and bone materials, respectively. In our experiments, the ratio of electron density as a function of H was obtained the 0.001026H+1.00 in soft tissue and 0.000304H+1.07 for bone at 130 KVp spectrum and showed 0.000274H+1.10 for bone tissue in low 110 KVp. This experiments of electron density calibrations from CT number used to decide depth and length of photon transportation. The Computed superposition and FFT convolution dose showed very close to measurements within 1.0% discrepancy in homogeneous phantom for 6 and 15 MV X rays, but it showed -5.0% large discrepancy in FFT convolution for bone tissue correction of 6 MV X rays. In this experiments, the evaluated doses showed acceptable discrepancy within -1.2% of average for lung and -2.9% for bone equivalent materials with superposition method in 6 MV X rays. However the FFT convolution method showed more a large discrepancy than superposition in the low electron density medium in 6 and 15 MV X rays. As the CT number depends on energy spectrum of X rays, it should be confirm gradient of function of CT number-electron density regularly.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.51-54
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• 1979

Research and Analisis for the qualities of chest films of emergency cases were completed in order to produce a valuable one of diagnostic necessity. It is resulted as follows; 1. Among the 3,505 cases of chest films, 47% of them was poor conditioned the reason was fowned as of unsuitable exposure. 2. It become the same condition when we increased 11.4% of KVp in full exhalation compare with the full inhalation of erect position and 20% after full exhalation and 4.3% after full inhalation in supine position. The result was that no difference between prone position and supine position was fowned. 3. When respiration volume is different, proper control of KVp is extremely needed.