• Journal of radiological science and technology
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• v.37 no.3
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• pp.177-185
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• 2014

This study focused on effects of patient exposure dose reduction with AEC (Auto Exposure Control) marker that is designed for showing location of AEC in X-ray Chest radiography. It included 880 adults who have to use Chest X-ray Digital Radiography system (DRS, LISTEM, Korea). AEC (Ion chambers are posited in top of both sides) are used to every adult and set X-ray system as Field size $17{\times}17inch$, 120kVp, FFD 180cm. 440 people of control group are posited on detector to include both sides of lung field and the other 440 people of experimental group are set to contact their lung directly to Ion chamber (making marker to shows location). Then, measured every DAP and, estimated patient effective dose by using PCXMC 2.0. The average age of control group (M:F=245:195) is 53.9 and the average BMI is 23.4. BMI ranges from under weight: 35, normal range: 279, over weight: 106 to obese: 20 and average DAP is 223.56mGycm2, Mean effective dose is 0.045mSv. The average age of experimental group (M:F=197:243) is 53.7 and the average BMI is 22.7. BMI ranges from under weight: 34, normal range: 315, over weight: 85 to obese: 6 and average DAP is 207.36mGycm2, Mean effective dose is 0.041mSv. Experimental group shows less Mean effective dose as 0.004mSv (9.7%) than control group. Also, patient numbers who got over exposure more than 0.056mSv (limit point to know efficiency of AEC marker) is 65 in control group (14.7%), 19 in experimental group (4.3%) and take statistics with t-Test. The statistical difference between two groups is 0.006. In order to use proper amount of X-ray in auto exposure controlled chest X-ray system, matching location between ion chamber and body part is needed, and using AEC marker (designed for showing location of ion chamber) is a way to reduce unnecessary patient exposure dose.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.619-627
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• 2016

The purpose of this study is to investigate the effect of CT contrast agent and MRI contrast agent on the area dose in the body when using automatic exposure control system in general radiography. After making rectangular holes in the center of the abdominal thickness paraffin phantom, CT contrast agent and MRI contrast agent were respectively diluted with physiological saline solution for contrast medium dilution ratio of 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, 0:10%. Each experiment was set to 78 kVp, 320 mA, which is the proper condition for KUB photography, and thereafter a total of 30 inspections were made for each dilution ratio using an automatic exposure control device, and the area dose corresponding to the dilution ratio of each contrast agent, Average comparison and correlation analysis were performed on the exposure index. As a result, the CT contrast agent and the MRI contrast agent appeared different in area dose according to the dilution ratio(p<0.05), and as the dilution ratio increased, the area dose increased for CT contrast agent and MRI contrast agent(P<0.05). In each test, the exposure index showed the manufacturer's recommendation of 200-800 EI value, and the exposure index and area dose increased as the area dose increased(p<0.05). In conclusion, CT contrast agent and MRI contrast agent confirmed to increase the area dose by general imaging test using all automatic exposure control device. Therefore, it is considered that it is necessary to perform it after the contrast medium has been excreted sufficiently when using usual imaging test after using the contrast agent in CT and MRI examination.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.567-573
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• 2017

The purpose of this study was to evaluate whether or not there was artifact when the upper limb could not be lifted to the top of the head during multi-detector computed tomography(MDCT) scans of the chest and abdomen. Contrast radiography of the human and chest phantom was performed with 128channal MDCT. Under the same conditions(120 kVp, 110 mAs, standard algorithm)both hands lifted up and put down each time in the human experiment. In the chest phantom experiment, the radiography was carried out when the upper limb phantom was adjusted at a certain distance(0, 3, 7 cm) from the chest phantom. Subsequently, the values of Noise, CT number, SNR, and CNR were measured in the field of concern. The noise value of fat, rib, and muscle increased when the arm was lifted in humans(0.79, 47.8, 27%). Furthermore, when the upper limb was lowered, the noise value of muscle and lung increased in the phantom(31.2, 9.4%). In addition, the noise value of the muscles and lung decreased by 5, 25.12% and 5.6, 15.35% as the upper limb moved about 0,3,7cm away from the chest. When the chest and abdominal radiography were performed, in the case of the presence of other parts outside the inspection area, the probability of artifact was minimal while the distance was more than 3cm away from the upper limb to the chest and abdomen.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.73-79
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• 2009

Purpose : We undertook this study to improve our understanding of the epidemiologic and clinical features of nonpolioenterovirus (NPEV) infections, especially enterovirus 71 (EV71) infections, in Korean children. Methods : Between April and June 2000, NPEVs were detected by RT-PCR and cultures of specimens obtained from patients with aseptic meningitis, acute respiratory disease, and acute gastroenteritis which were associated with enteroviral exanthem and vesicular pharyngeal enanthem, such as herpangina, and hand, foot, and mouth disease (HFMD). EV71 was identified by sequencing the VP1 gene. The clinical and epidemiologic data were analyzed retrospectively after all 87 NPEV-positive patients were divided into 4 groups, according to the clinical manifestations. Sixteen patients who mainly had symptoms of acute gastroenteritis were in group A, 21 patients with symptoms and signs of lower respiratory tract infections were in group B, 42 patients with a HFMD rash only were in group C with or without fever, and 8 patients with aseptic meningitis or paralysis were in group D. For the 11 EV71-positive patients, 1 was in group A, 2 were group B, 7 were in group C, and 1 was in group D. Results : There were 87 NPEV infections, including 11 EV71 infections. The mean age of the patients was 2 years and 11 months, ranging from 1 day to 15 years. There were no fatal cases among a total of 87 NPEV infections and no significant differences in clinical severity between the EV71 and other NPEV infections. Conclusion : NPEV infections in children were common during the 3 months in the spring of 2000. Unlike in southeast Asia, where fatal EV71 infection outbreaks have occurred since 1997, the clinical features of EV71 infection in Korean children are mild.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1149-1155
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• 2023

This study aims to investigate the effect of changes in the Sub ROI on exposure index(EI) and to present indicators of changes in EI values that may occur when changing Sub ROI in clinical practice. This study was conducted on a subject of 20 cm of acrylic for a setting similar to abdominal radiography, and the specifications of one acrylic sheet is 20 × 20 × 5 cm. The survey conditions were the same as 80 kVp , 320 mA, 25 ms, SID 110 cm and the Sub ROI obtained 30 images for each type using five types provided by the equipment company. The EI value provided by the equipment and entrance skin exposure(ESE) were compared and analyzed. The mean value of EI according to the change in Sub ROI was 101.18±0.27 for LS, 106.57±0.31 for AEC, 107.74±0.39 for VR, 107.90±0.38 for HR, and 109.72±0.32 for SS (p<0.01). The average value of ESE by sub ROI type (LS, AEC, VR, HR, SS) was measured to be 476.45±1.71 μGy, 476.92±1.48 μGy, 476.14±2.30 μGy, 475.61±1.96 μGy, and 477.14±1.46 μGy, with statistically significant differences (p<0.01). As a result of this study, the EI according to the sub ROI type is based on LS(109.72), which represents the minimum value. AEC increased 5.3%, VR increased 6.4%, HR increased 6.6%, SS increased 8.4%, and overall, increased by about 5.3%. As for the average value of ESE, HR(475.61 μGy)type showed the minimum value, and based on this, AEC increased 0.27%, VR increased 0.11%, LS increased 0.17%, SS increased 0.32%, and overall, increased by about 0.17%.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.71-78
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• 2021

Purpose: To evaluate the inter-fractional position and respiratory reproducibility of lung and liver tumors using pressure conserving type(P-type) abdominal compressor in volumetric modulated arc therapy(VMAT). Materials and methods: Six lung cancer patients and three liver cancer patients who underwent VMAT using a P-type abdominal compressor were included in this study. Cone-beam computed tomography(CBCT) images were acquired before each treatment and compared with planning CT images to evaluate the inter-fractional position reproducibility. The position variation was defined as the difference of position shift values between target matching and bone matching. 4-dimensional cone-beam computed tomography(4D CBCT) images were acquired weekly before treatment and compared with planning 4DCT images to evaluate the inter-fractional respiratory reproducibility. The respiratory variation was calculated by the magnitude of excursions by breathing. Results: The mean ± standard deviation(SD) of overall position variation values, 3D vector in the three translational directions were 1.1 ± 1.4 mm and 4.5 ± 2.8 mm for the lung and liver, respectively. The mean ± SD of respiratory variation values were 0.7 ± 3.4 mm (p = 0.195) in the lung and 3.6 ± 2.6 mm (p < 0.05) in the liver. Conclusion: The use of P-type compressor in lung and liver VMAT was effective for stable control of inter-fractional position and respiratory variation by reproduction of abdominal compression. Appropriate PTV margin must be considered in treatment planning, and image guidance before each treatment are required in order to obtain more stable reproducibility

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.183-194
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• 1988

This study was carried out to investigate for resistance of V. parahaemolyticus that isolated from patients of food poisoning and fish and shellfish, captured in east coast of Kyungpook province of Korea from 1985 to 1986. VP ATCC 17802 and NAG V. ATCC 6538 were used as control. In fish, shellfish and seaweed, the more temperature increased, the shorter survival time was. In case of sea-water, the more temperature rose up, the longer survival time was, particularly in $37^{\circ}C$ and $25^{\circ}C$, the strains had survived after 6 months. And in tapwater, it was sterilized in 150 mins. and survived for 11.5 days on maximum in ground water. In kimchi, at room temperature, germicidal time was shorter more than 6 times compared with that which had been kept in refrigerator. It survived for 57.1 days in milk, 49.2 mins. in yougurt. Strains had been surviving in frozen condition at $-70^{\circ}C$ even after 6 months, present study time. In resistance test in water bath at several degrees of temperature, all the strains were sterilized in 20 mins. with $60^{\circ}C$. In resistance test to driness, number of surviving strains dropped rapidly in 10-11%) water contents. In UV $2538{\AA}$, strains were sterilized in 20 mins. In resistance test to alcohol, strains had survived for 0.1-4 mins. in fermentative wine of below than 25% and distilled wine of over than 25% in alcohol concentration. The bactericidal concentration of disinfectant was 1% in phenol and 3% in cresol. In 0.1M acetic acid and 0.1M lactic acid, number of surviving colonies decreased rapidly but not in citric acid. The more NaCl concentration rose up, the lower decreasing rate of number of surviving colonies was. The strains had showed sensitive response to vancomycin, chloramphenicol, gentamicin, and resisted to carbenicillin, ampicillin and kanamycin. When one day culture strain was cultured till 25th day, resistant strains to tetracycline and cephalothin were changed to sensitive.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.367-377
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• 1993

Background: The benefits of combination chemotherapy in unresectable non-small cell lung cancer remain uncertain. But, according to the recent reports, the response rates of cisplatin-based polychemotherapy regimens are higher than those of single agent. Also, the response rates of high-dose cisplatin group are higher than those of low-dose cisplatin group. In attemp to answer the question whether treatments, combination chemotherapy (high VPP) and combination chemotherapy with radiation therapy, improve survival in advanced non-small cell lung cancer, we begin to study. Method: Thirty-five patients above stage III, diagnosed histologically as non-small cell lung cancer, were enrolled. Among them, nineteen received a combination chemotherapy consisting of VP-16 & high-dose cisplatin (100 $mg/m^2$) and/or radiation therapy. The other group (16 subjects) received no therapy. To investigate the differences of survival and response rates between two groups and the side effects related to therapy, we reviewed patients' records. Results: 1) The overall objective response rate was 47%(9/19) with one complete remission. 2) In patients who received polychemotherapy and radiation therapy, the response rate was 60%(6/10) with one complete remission and survival rates of 3 months, 6 months and 12 months were 100%, 70% and 40%. 3) In patients who received polychemotherapy, the response rate was 33% (3/9) with no complete remission and survival rates of 3 months, 6 months and 12 months were 78%, 67% and 33%. 4) Overall, treated patients survived significantly longer (p<0.05) than non-treated patients (median survival 307 days versus 95 days). 5) Analysis of the various prognostic factors disclosed that good performance status, stage III and squamous cell type showed the good response rates. 6) The toxicities were nausea and/or vomiting (100%), alopecia (90%), anemia (79%), leukopenia (69%), thrombocytopenia (2%), increased creatinine (16%) and neurotoxicity (5%). Conclusion: According to above results, there are relatively good results that high VPP combination chemotherapy in advanced non-small cell lung cancer improves survival in the treated group than in the non-treated group. Thus, it is considerd that we select the patients with proper indications and treat them with effective chemotherpy and radiation therapy. But, because improvement related to high VPP ploychemotherapy is not marked in this study, it is necessary that we should investigate follow-up studies in many cases.

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.7-12
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• 2004

Purpose: To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. Materials and Methods: 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. Results: The mean length of incisive canal was 15.87 mm±2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm±0.76 and 3.89 mm± 1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3°±6.96 and 117.45°±7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r= 0.258). Conclusion : This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.77-84
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• 2013

Purpose: This study aimed to provide comparative measurements of the effective dose from direct and indirect digital panoramic units according to phantoms and exposure parameters. Materials and Methods: Dose measurements were carried out using a head phantom representing an average man (175 cm tall, 73.5 kg male) and a limbless whole body phantom representing an average woman (155 cm tall, 50 kg female). Lithium fluoride thermoluminescent dosimeter (TLD) chips were used for the dosimeter. Two direct and 2 indirect digital panoramic units were evaluated in this study. Effective doses were derived using 2007 International Commission on Radiological Protection (ICRP) recommendations. Results: The effective doses of the 4 digital panoramic units ranged between $8.9{\mu}Sv$ and $37.8{\mu}Sv$. By using the head phantom, the effective doses from the direct digital panoramic units ($37.8{\mu}Sv$, $27.6{\mu}Sv$) were higher than those from the indirect units ($8.9{\mu}Sv$, $15.9{\mu}Sv$). The same panoramic unit showed the difference in effective doses according to the gender of the phantom, numbers and locations of TLDs, and kVp. Conclusion: To reasonably assess the radiation risk from various dental radiographic units, the effective doses should be obtained with the same numbers and locations of TLDs, and with standard hospital exposure. After that, it is necessary to survey the effective doses from various dental radiographic units according to the gender with the corresponding phantom.