• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.47-52
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• 2018

Brain perfusion CT scanning is often employed usefully in clinical conditions as it accurately and promptly provides information about the perfusion state of patients having acute ischemic stroke with a lot of time constraints and allows them to receive proper treatment. Despite those strengths of it, it also has a serious weakness that Lens may be exposed to a lot of dose of radiation in it. In this study, as a way to reduce the dose of radiation to Lens in brain perfusion CT scanning, this researcher conducted an experiment with Bismuth shielding and change of patients' position. TLD (TLD-100) was placed on both lens using the phantom (PBU-50), and then, in total 4 positions, parallel to IOML, parallel to IOML (Bismuth shielding), parallel to SOML, and parallel to SOML (Bismuth shielding), brain perfusion scanning was done 5 times for each position, and dose to Lens were measured. Also, to examine how the picture quality changed in different positions, 4 areas of interest were designated in 4 spots, and then, CT number and noise changes were measured and compared. According to the results of conducting one-way ANOVA on the doses measured, as the significance probability was found to be 0.000, so there was difference found in the doses of radiation to crystalline lenses. According to the results of Duncan's post-hoc test, with the scanning of being parallel to IOML as the reference, the reduction of 89.16% and 89.66% was observed in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding) respectively, so the doses to Lens reduced significantly. Next, in the scanning of being parallel to IOML (Bismuth shielding), the reduction of 37.12% was found. According to the results, reduction in the doses of radiation was found the most significantly both in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding). With the limit of the equivalent dose to Lens as the reference, this researcher conducted comparison with the dose to occupational exposure and dose to Public exposure in the scanning of being parallel to IOML and found 39.47% and 394.73% respectively; however in the scanning of being parallel to SOML (Bismuth shielding), considerable reduction was found as 4.08% and 40.8% respectively. According to the results of evaluation on picture quality, every image was found to meet the evaluative standards of phantom scanning in terms of the measurement of CT numbers and noise. In conclusion, it would be the most useful way to reduce the dose of radiation to Lens to use shields in brain perfusion CT scanning and adjust patients' position so that their lens will not be in the field of radiation.

• Journal of Veterinary Clinics
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• v.30 no.5
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• pp.346-352
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• 2013

The study was aimed to investigate the influence of diode laser on osteoarthritis (OA) of stifle joint induced by anterior cruciate ligament transection (ACLT). Sixty 10-week-old male Sprague-Dawley rats were used in this study. Right stifle joint was operated to create ACLT or sham. There were five study groups: control, Sham, ACLT, ACLT + Laser irradiation (ACLT+L) and ACLT + meloxicam administration (ACLT+M). Low-level laser therapy (LLLT) was applied at the operated stifle joint twice a week using an 808-nm indium-gallium-arsenide (InGaAs) diode laser during 8-week experimental period. Radiographical, gross morphological and histopathological findings were examined at 2, 4 and 8 weeks post-surgery. Radiography, CBC and chemistry tests showed no significant difference between groups. ACLT+L group showed remarkable cartilage damages compared with sham group morphologically and histopathologically at 2, 4 and 8 weeks after surgery. ACLT+M group also had more cartilage damages compared with sham group. Low-level laser therapy (LLLT) showed limitation to prevent progression of OA in the rat anterior cruciate ligament transection models; on the contrary it accelerated cartilage damage. It is assumed that the aggravating results of LLLT in this study might be due to excessive unstable movement of stifle joint from the pain-relieving effect of LLLT, rather than direct damaging effect of irradiation since LLLT did not affect cell viability.

• Progress in Medical Physics
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• v.24 no.1
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• pp.48-53
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• 2013

Monte Carlo method has been known as the most accurate method for calculating absorbed dose in the human body, and an anthropomorphic phantom has been mainly used as a method of simulating internal organs for using such a calculation method. However, various efforts are made to extract data on several internal organs in the human body directly from CT DICOM files in recent Monte Carlo calculation using Geant4 code and to use by converting them into the geometry necessary for simulation. Such a function makes it possible to calculate the internal absorbed dose accurately while duplicating the actual human anatomical structure. Thus, this study calculated the absorbed dose in the human body by using Geant4 associating with DICOM files, and aimed to confirm the usefulness by compare the result with the measured dose using a Gafchromic EBT2 film. This study compared the dose calculated using simulation and the measured dose in beam central axis using the EBT2 film. The results showed that the range of difference was an average of 3.75% except for a build-up region, in which the dose rapidly changed from skin surface to the depth of maximum dose. In addition, this study made it easy to confirm the target absorbed dose by internal organ and organ through the output of the calculated value of dose by CT slice and the dose value of each voxel in each slice. Thus, the method that outputs dose value by slice and voxel through the use of CT DICOM, which is actual image data of human body, instead of the anthropomorphic phantom enables accurate dose calculations of various regions. Therefore, it is considered that it will be useful for dose calculation of radiotherapy planning system in the future. Moreover, it is applicable for currently-used several energy ranges in current use, so it is considered that it will be effectively used in order to check the radiation absorbed dose in the human body.

• Journal of the Korean Society of Radiology
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• v.9 no.3
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• pp.147-168
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• 2015

In this research, we have analyzed the impact factors on the bone mineral density thru the examination of bone density difference in the entire femur, femoral neck and lumbar of adult women before the menopause in accordance with the general features, lifestyle, eating habits, health and body composition. The survey was conducted among adult women before the menopause and older than 30 years based on the data of the National Health and Nutrition Examination Survey carried out in the 4th term (2008-2009) and 5th term (2010-2011) and we would like to provide the research results for the establishment of recommendations or guidelines for the treatment of adult women before the menopause with regard to the impact factors on the bone mineral density and for the development of health education materials for the accurate measurement of bone mineral density of young women in order to prevent the postmenopausal osteoporosis. With respect to the general features of adult women before the menopause, the bone mineral density was higher in the entire femur at age 40-44, femoral neck at 35-39, in high-school education level, in the earlier menarche group, without smoking experiences, with regular walking time and exercise frequency and with the habits of eating no hamburger or pizza. With regard to the body composition, the bone mineral density was higher in obesity and lower in underweight cases, higher among people with abdominal obesity and weight control experiences. In terms of total body fat ratio, total amount of fat and muscle, the bone mineral density got gradually increased from the 1st quarter (Q1) to the 4th quarter(Q4). The obesity, disease, total amount of fat and muscle were shown to be significantly related with the bone mineral density in this research and it is required for young women to keep the adequate weight and the normal BMI in order to increase the bone mineral density. For the prevention of osteoporosis, it is advised to keep the right habits including regular exercise and no smoking discipline from the growing period and achieve the maximum bone mass thru the control of proper weight from a young age.

• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.5-10
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• 2012

There is a still unsettled issue about the comparison of long-term clinical effects between sirolimus-(SES) and paclitaxel-eluting stents (PES) for the patients with acute myocardial infarction (AMI). Therefore, we performed a retrospective analysis to evaluate the 4-year clinical outcome of SES as compared with PES after percutaneous coronary intervention (PCI) in patients with AMI. From January 2004 to August 2006, all consecutive patients with acute ST-segment elevation myocardial infarction (STEMI) underwent primary PCI and acute NSTEMI underwent PCI by implantation either SES or PES were enrolled. The occurrence of death, cardiac death, recurrent infarction, target vessel revascularization (TVR) and stent thrombosis were analyzed. The composite of major adverse cardiac events (MACE; death, recurrent infarction and TVR) were also analyzed. During the study period, total 668 AMI patients had visited. Of them, total 522 patients (299 with SES and 223 with PES) were enrolled. During 4-year clinical follow-up, there were similar occurrences of death ($18.3{\pm}3.0%$ vs. $14.6{\pm}2.2%$, p=0.26), cardiac death ($11.2{\pm}2.6%$ vs. $6.8{\pm}1.52%$, p=0.39), re-infarction ($6.4{\pm}1.8%$ vs. $3.3{\pm}1.1%$, p=0.31), and stent thrombosis ($5.4{\pm}1.7%$ vs. $3.2{\pm}1.1%$, p=0.53) between the two groups, consecutively. The occurrences of TVR ($10.0{\pm}3.0%$ vs. $4.0{\pm}1.2%$, p=0.008) and MACE ($29.4{\pm}3.5%$ vs. $19.4{\pm}2.5%$, p=0.003) were significantly higher in patients treated with PES than SES. In AMI patients treated with either SES or PES implantation, SES had a significantly lower risk of TVR and MACE during 4-year clinical follow-up. Rates of death, cardiac death or recurrent infarction, and stent thrombosis were similar.

• Journal of the Korean Society of Radiology
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• v.1 no.1
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• pp.17-23
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• 2007

Background: Cerebrovascular diseases are known to show different patterns of incidence among regions and races. Therefore, it is very important to determine the incidence pattern of a specific area in order to diagnose, treat and prevent cerebrovascular diseases. The objective of the present study is to analyze quantitatively the incidence ratios of hemorrhagic and ischemic cerebrovascular diseases by season, by gender and by age. Methods: The subjects of this study were 1603 patients hospitalized for hemorrhagic or ischemic cerebrovascular diseases at the Department of Neurosurgery or the Department of Neurology of a University Hospital. Statistical analysis of data used Excel 2003 of Microsoft, and t-test was conducted using ORIGIN 6.0 of MICROCAL. Results: In the subjects, the incidence ratios of hemorrhagic and ischemic cerebrovascular diseases for four years, the period of this research, were 38.55% and 61.45%, respectively. The mean and standard deviation of age when hemorrhagic cerebrovascular diseases occurred were 58.20 and 12.60, respectively, and the percentages of subjects in their 40s, 50s, 60s and 70s were all around 20%. On the contrary, the mean and standard deviation of age when ischemic cerebrovascular diseases occurred were 65.01 and 13.59, respectively. The average age of patients with ischemic cerebrovascular diseases was older than that of patients with hemorrhagic brain diseases, and the percentages of those in their 60s, 70s and 80s were 15.53%, 37.06% and 27.72%, respectively. The season when hemorrhagic cerebrovascular diseases appeared most frequently was winter, which was followed by summer, spring and autumn. The season when hemorrhagic cerebrovascular diseases appeared most frequently was spring, which was followed by summer, winter and autumn. Conclusions: In this study, the incidence rates of hemorrhagic and ischemic cerebrovascular diseases were 38.55% and 61.45%, showing the rising percentage of ischemic cerebrovascular diseases. For making adequate prevention and disease control plans, it is considered necessary to make a long-term epidemiological investigation of cerebrovascular diseases.

• Progress in Medical Physics
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• v.24 no.4
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• pp.253-258
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• 2013

The purpose of this study is to evaluate and analyze the relationship between the external radiation dose reconstruction which is transmitted from the patient who receives radiation treatment through electronic portal imaging device (EPID) and the internal dose derived from the Monte Carlo simulation. As a comparative analysis of the two cases, it is performed to provide a basic indicator for similar studies. The geometric information of the experiment and that of the radiation source were entered into Monte Carlo n-particle (MCNPX) which is the computer simulation tool and to derive the EPID images, a tally card in MCNPX was used for visualizing and the imaging of the dose information. We set to source to surface distance (SSD) 100 cm for internal measurement and EPID. And the water phantom was set to be 100 cm of the source to surface distance (SSD) for the internal measurement and EPID was set to 90 cm of SSD which is 10 cm below. The internal dose was collected from the water phantom by using mesh tally function in MCNPX, accumulated dose data was acquired by four-portal beam exposures. At the same time, after getting the dose which had been passed through water phantom, dose reconstruction was performed using back-projection method. In order to analyze about two cases, we compared the penetrated dose by calibration of itself with the absorbed one. We also evaluated the reconstructed dose using EPID and partially accumulated (overlapped) dose in water phantom by four-portal beam exposures. The sum dose data of two cases were calculated as each 3.4580 MeV/g (absorbed dose in water) and 3.4354 MeV/g (EPID reconstruction). The result of sum dose match from two cases shows good agreement with 0.6536% dose error.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.567-574
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• 2022

Coronary artery disease (CAD) and atrial fibrillation (AF) are known to share many risk factors. In particular, in the case of acute coronary syndrome, it may be difficult to clearly determine the diameter of the vessel due to complete occlusion of the vessel and thrombus. Thus, the relationship between the diameter of the coronary arteries was evaluated to be used as a reference data before the treatment of coronary arteries and drug selection in patients with AF. From January 2020 to August 2022, images of coronary angiography (CAG) with AF and normal sinus rhythm (NSR) on electrocardiography were target. In both subjects, images of normal coronary artery without lesions as a result of CAG were used. For all vessels, the diameters of the vessels were measured by dividing them into proximal, middle, and distal parts, and the measured diameters were divided by the average for evaluation. As a result of analyzing the left anterior descending artery diameter, the vessel diameter of the AF patient was 2.24±0.26 mm, which was smaller than that of the NSR patient, 2.86±0.38 mm, and was statistically significant. (p<0.001) As a result of analyzing the left circumflex artery diameter, the vessel diameter of the AF patient was 2.34±0.28 mm, which was smaller than the vessel diameter of the NSR patient, 2.87±0.29 mm, and was statistically significant. (p<0.001) As a result of analyzing the diameter of the right coronary artery, the vessel diameter of the AF patient was 2.68±0.5 mm, which was smaller than the vessel diameter of the NSR patient, 3.35±0.4 mm, and was statistically significant. (p<0.001) Considering that the coronary artery size of AF patients is significantly smaller than the coronary vessel size of NSR patients, it is considered as a useful study to be used as a reference for evaluating coronary artery diameter when the arrhythmia is AF. In particular, it is considered to be a study that can be helpful in diagnosing lesions, using drugs before and after surgery, and choosing to use auxiliary devices such as intravascular ultrasound.

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.187-201
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• 2024

Osteoporosis is a major health issue globally, often remaining undetected until a fracture occurs. To facilitate early detection, deep learning (DL) models were developed to classify osteoporosis using abdominal computed tomography (CT) scans. This study was conducted using retrospectively collected data from 3,012 contrast-enhanced abdominal CT scans. The DL models developed in this study were constructed for using image data, demographic/clinical information, and multi-modality data, respectively. Patients were categorized into the normal, osteopenia, and osteoporosis groups based on their T-scores, obtained from dual-energy X-ray absorptiometry, into normal, osteopenia, and osteoporosis groups. The models showed high accuracy and effectiveness, with the combined data model performing the best, achieving an area under the receiver operating characteristic curve of 0.94 and an accuracy of 0.80. The image-based model also performed well, while the demographic data model had lower accuracy and effectiveness. In addition, the DL model was interpreted by gradient-weighted class activation mapping (Grad-CAM) to highlight clinically relevant features in the images, revealing the femoral neck as a common site for fractures. The study shows that DL can accurately identify osteoporosis stages from clinical data, indicating the potential of abdominal CT scans in early osteoporosis detection and reducing fracture risks with prompt treatment.

• Radiation Oncology Journal
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• v.21 no.2
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• pp.149-157
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• 2003

Purpose: The purpose of this study was to determine if there were prognostic differences between BRCA related and BRCA non-related Korean patients with early-onset breast carcinomas. Materials and Methods: Sixty women who had developed breast cancers before the age of 40, and who were treated at the Soonchunhyang University Hospital, were studied independently of their family histories. The age range was 18 to 40 with a median of 34.5 years. Lymphocyte specimens from peripheral blood were studied for the heterozygous mutations of BRCA1 and BRCA2 using direct sequencing methods. Immunohistochemistry was peformed on the paraffin-embedded tissue blocks that were available. Results: Eleven deleterious mutations (18.3%, 6 in BRCA1 and 5 in BRCA2) and 7 missense mutations of unknown significance (11.7%), were found among the 60 patients. More than half of the mutation were novel, and were not reported in the database. Most of the BRCA-associated patients had no history of breast cancer. No treatment related failures were observed in the BRCA carriers, with the exception of one patient that had experienced a new primary tumor of the contralateral breast. The seven year relapse free survival rate were 50 and 79% In the BRCA carrier and BRCA negative patients, respectively. Although the expression of estrogen and progesterone receptors were less common, and histological features more aggressive, in the BRCA associated tumors, the outcome of the patients with BRCA mutations was not poorer than that on the patients without deleterious mutations. Conclusion.: Despite the BRCA mutation carriers having adverse prognostic features, the recurrence rate was relatively lower than that in the BRCA non-carrying Korean patients wi4h early-onset breast carcinomas. In addition, although the prevalence of the BRCA mutation in Korean patients was higher than that in white patients, the penetrance of the cancer seemed to be relatively low in Korean women carrying BRCA mutations. A large population based study of the BRCA mutation, with a long-term follow-up of the study patients will be required to confirm these results.