• Progress in Medical Physics
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• v.19 no.1
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• pp.80-88
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• 2008

Recent radiotherapy dose planning system (RTPS) generally adapted the kernel beam using the convolution method for computation of tissue dose. To get a depth and profile dose in a given depth concerened a given photon beam, the energy spectrum was reconstructed from the attenuation dose of transmission of filter through iterative numerical analysis. The experiments were performed with 15 MV X rays (Oncor, Siemens) and ionization chamber (0.125 cc, PTW) for measurements of filter transmitted dose. The energy spectrum of 15MV X-rays was determined from attenuated dose of lead filter transmission from 0.51 cm to 8.04 cm with energy interval 0.25 MeV. In the results, the peak flux revealed at 3.75 MeV and mean energy of 15 MV X rays was 4.639 MeV in this experiments. The results of transmitted dose of lead filter showed within 0.6% in average but maximum 2.5% discrepancy in a 5 cm thickness of lead filter. Since the tissue dose is highly depend on the its energy, the lateral dose are delivered from the lateral spread of energy fluence through flattening filter shape as tangent 0.075 and 0.125 which showed 4.211 MeV and 3.906 MeV. In this experiments, analyzed the energy spectrum has applied to obtain the percent depth dose of RTPS (XiO, Version 4.3.1, CMS). The generated percent depth dose from $6{\times}6cm^2$ of field to $30{\times}30cm^2$ showed very close to that of experimental measurement within 1 % discrepancy in average. The computed dose profile were within 1% discrepancy to measurement in field size $10{\times}10cm$, however, the large field sizes were obtained within 2% uncertainty. The resulting algorithm produced x-ray spectrum that match both quality and quantity with small discrepancy in this experiments.

• Tuberculosis and Respiratory Diseases
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• v.39 no.1
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• pp.28-34
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• 1992

Background: Diffuse panbronchiolitis (DPB) is a chronic obstructive pulmonary disease distinguished from bronchial asthma, chronic bronchitis, pulmonary emphysema, bronchiectasis, or alveolitis. It is prevalent in Japan, but is known to be rare outside of Japan. Only a few cases in Chinese, Italian, Noirth American and Korean have been reported. During recent two years we have found 16 cases of DPB in Seoul National University Hospital and analyzed the clinical characteristics. Method: We reviewed the patients' age, sex, duration of illness, smoking history, occupational history and past medical history. And we analyzed patients' symptoms, physical signs, laboratory findings and responses to treatment. Results: 1) Male: female ratio was 2.2:1, the ages ranged from 27 to 72 years old, and the duration of disease varied from 1 to 20 years. 2) Most of the patients were being treated as bronchiectasis, miliary tuberculosis, chronic bronchitis or bronchial asthma before they were diagnosed as DPB. 3) Only one patient was a smoker, and 25% of patients had the occupational history of exposure to particles or gas. And all patients had paranasal sinusitis. 4) High resolution computed tomography (HRCT) was very useful in diagnosing the disease in most of the patients. 5) PFT showed obstructive and restrictive abnormalities, and blood gas revealed hypoxemia in most of the patients. 6) Pseudomonas aeruginosa was isolated in the sputum of four patients (25%). 7) The titers of cold hemaglutinin, RA factor and CRP were elevated in most of the patients. 8) Most of the patients improved after treatment with erythromycin. Conclusion: DPB might not be a rare disease in Korea. So DPB should be suspected in a patient who has chronic cough, sputum, dyspnea and diffuse fine nodular chest X-ray abnormality. HRCT and open lung biopsy should be considered in a patient suspected of DPB.

• Journal of Gastric Cancer
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• v.5 no.4 s.20
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• pp.222-227
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• 2005

Purpose: There are several reports suggested the usefulness of serum tumor markers, AFP, CEA and CA19-9 as prognostic factors or indicators for recurrence in gastric cancer. This clinical study was peformed to evaluate positive rate of tumor markers according to site of recurrence in gastric cancer. Materials and Methods: From the database of patients who underwent radical gastrectomy for gastric cancer between January 1999 and January 2004, 52 patients who showed recurrence were included in this retrospective study. Serum levels of tumor markers were measured at the time of preoperative diagnosis of the gastric cancer and at the time of postoperative recurrence during follow up, respectively. Results: The overall positivity of tumor markers at the time of recurrence was found to be significantly higher than that of prior to surgery in the recurred group for the single test as well as the combination tests. For the peritoneum, the most common recurrent site, the positivity of CA19-9 was higher at the time of recurrence. And the significant positivity of CEA at the time of recurrence was detected in the liver cases. Conclusion: Having a preoperative positive tumor marker may identify the patient as having an increased chance of a recurrence. Although tumor markers continue to have limited diagnostic significance in gastric cancer, CA19-9 may be useful as a predictor for peritoneal recurrence of the gastric cancer, and CEA for recurrence to liver.

• Journal of the Korean Society of Radiology
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• v.10 no.5
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• pp.327-335
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• 2016

The study is enforce to study image quality evaluation of condition provide the IEC and combination of clinical conditions each quality of radiation that image quality to assess the conditions provided to IEC in the clinical environment to conduct image quality assessment of the digital radiography system in the detector have environmental limits. First, image quality evaluation was evaluated by measuring the MTF, NPS using four quality of radiation and Using MCNPX simulation lastly DQE make a image quality evaluation after calculating the particle fluence to analyze spectrum quality of radiation. Second, Using MCNPX simulation of four quality of radiation was evaluated absorbed dose rate about electronic 1 per unit air, water, muscle, bone by using Radiation flux density and energy, mass-energy absorption coefficient of matter. Results of evaluation of image quality, MTF of four quality of radiation was satisfied diagnosis frequency domain 1.0 ~ 3.0 lp/mm of general X-ray that indicated 1.13 ~ 2.91 lp/mm spatial frequency. The NPS has added filter, spatial frequency 0.5 lp/mm at standard NPS showed a tendency to decrease after increase. Unused added filter, spatial frequency 0.5 lp/mm at standard NPS showed a certain NPS result value after decrease. DQE in 70 kVp / unuesd added filter(21 mm Al) / SID 150 cm that patial frequency 1.5 lp/mm at standard showed a tendency to decrease after certain value showed. Patial frequency in the rest quality of radiation was showed a tendency to decrease after increase. Results of evaluation of absorbed dose, air < water < muscle < bone in the order showed a tendency to increase. Based on the results of this study provide to basic data that present for the image quality evaluation method of a digital radiation imaging system in various the clinical condition.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.273-281
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• 2003

A stoichiometric mixture for $CdIn_2Te_4$ single crystal was prepared from horizontal electric furnace. The $CdIn_2Te_4$ single crystal was grown in the three-stage vertical electric furnace by using Bridgeman method. The quality of the grown crystal has been investigated by the x-ray diffraction and the photoluminescence measurements. The (001) growth plane of oriented $CdIn_2Te_4$ single crystal was confirmed from back-reflection Laue patterns. The carrier density and mobility of $CdIn_2Te_4$ single crystal measured with Hall effect by van der Pauw method are $8.61{\times}10^{16}\;cm^{-3}$ and $242\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CdIn_2Te_4$ single crystal obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.4750\;eV-(7.69{\times}10^{-3}\;eV)T^2/(T+2147)$. After the as-grown $CdIn_2Te_4$ single crystal was annealed in Cd-, In-, and Te-atmospheres, the origin of point defects of $CdIn_2Te_4$ single crystal has been investigated by the photoluminescence(PL) at 10 K. The native defects of $V_{Te}$, $Cd_{int}$, and $V_{Cd}$, $Te_{int}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Cd-atmosphere converted $CdIn_2Te_4$ single crystal to an optical n-type. Also, we confirmed that In in $CdIn_2Te_4$ did not form the native defects because In in $CdIn_2Te_4$ single crystal existed in the form of stable bonds.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.259-266
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• 2008

Objective : The purpose of this study was to examine the relationship between bone mineral density (BMD) and the metabolic syndrome. Method : We conducted a cross-sectional study of 1204 adults(males: 364 females: 840) in a general hospital health promotion center. They were grouped into the normal and lower BMD group according to bone loss(osteopenia, osteoporosis), as determined by duel energy X-ray absorptiometery(DEXA). We analyzed the association between BMD and metabolic syndrome by multiple logistic regression analysis. After adjustment for age, weight, alcohol intake, smoking, regular exercise, regular intake of meals, and menopausal status, odds ratios for the prevalence of the metabolic syndrome by gender were calculated for lower BMD. Results : After adjustment for the effect of potential covariates, the prevalence of metabolic syndrome was associated with bone loss in men(p<0.001). If the odds ratio of normal group is 1.00, then that of the lower BMD group is 3.07(95% CI=1.83-5.16). The prevalence of metabolic alterations fitting the criteria of metabolic syndrome was significantly decreased in High BMI, Low HDL in men and in High BMI in women(p<0.05). Conclusions : This study shows that BMD was associated with metabolic syndrome. Further studies needed to obtain evidence concerning the association between BMD and metabolic syndrome.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.68-80
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• 2012

Purpose : More recently, combined PET/MR scanners have been developed in which the MR data can be used for both anatometabolic image formation and attenuation correction of the PET data. For quantitative PET information, correction of tissue photon attenuation is mandatory. The attenuation map is obtained from the CT scan in the PET/CT. In the case of PET/MR, the attenuation map can be calculated from the MR image. The purpose of this study was to assess the quantitative differences between MR-based and CT-based attenuation corrected PET images. Materials and Methods : Using the uniform cylinder phantom of distilled water which has 199.8 MBq of $^{18}F$-FDG put into the phantom, we studied the effect of MR-based and CT-based attenuation corrected PET images, of the PET-CT using time of flight (TOF) and non-TOF iterative reconstruction. The images were acquired from 60 minutes at 15-minute intervals. Region of interests were drawn over 70% from the center of the image, and the Scanners' analysis software tools calculated both maximum and mean SUV. These data were analyzed by one way-anova test and Bland-Altman analysis. MR images are segmented into three classes(not including bone), and each class is assigned to each region based on the expected average attenuation of each region. For clinical diagnostic purpose, PET/MR and PET/CT images were acquired in 23 patients (Ingenuity TF PET/MR, Gemini TF64). PET/CT scans were performed approximately 33.8 minutes after the beginnig of the PET/MR scans. Region of interests were drawn over 9 regions of interest(lung, liver, spleen, bone), and the Scanners' analysis software tools calculated both maximum and mean SUV. The SUVs from 9 regions of interest in MR-based PET images and in CT-based PET images were compared. These data were analyzed by paired t test and Bland-Altman analysis. Results : In phantom study, MR-based attenuation corrected PET images generally showed slightly lower -0.36~-0.15 SUVs than CT-based attenuation corrected PET images (p<0.05). In clinical study, MR-based attenuation corrected PET images generally showed slightly lower SUVs than CT-based attenuation corrected PET images (excepting left middle lung and transverse Lumbar) (p<0.05). And percent differences were -8.01.79% lower for the PET/MR images than for the PET/CT images. (excepting lung) Based on the Bland-Altman method, the agreement between the two methods was considered good. Conclusion : PET/MR confirms generally lower SUVs than PET/CT. But, there were no difference in the clinical interpretations made by the quantitative comparisons with both type of attenuation map.

• Journal of the Korean Society of Radiology
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• v.11 no.2
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• pp.145-155
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• 2017

The purpose of this study was to compare and analyze changes in body composition and bone mineral density (BMD) during combined exercise in premenopausal women who did not take regular diet or regular physical activity within 6 months, In addition to being able to recognize the importance of pre-menopausal women's health and exercise, it also provides basic data for the development of educational programs for early prevention of osteoporosis prevention education I want to. The average age of the subjects in their 30s was 35.44 years and their height was 158.89 cm in their 30s. The average age of the subjects in their 40s was 41.89 and their average height was 160.78 cm in their 40s. Body composition, BMI, and body fat percentage were higher in the 30s, and bone mineral content, lean body mass, skeletal muscle mass, body weight, body fat mass and waist circumference were higher in their forties. Lumbar spine BMD and femur density were higher in their 30s than their 40s. Body composition, skeletal muscle mass, and fat mass increased in the 30s body composition by age - related complex exercise in premenopausal women, body fat mass, body fat percentage, waist circumference decreased. Body mass, body fat, body fat percentage, and BMI decreased in the 40s. The lumbar spine, the lumbar spine, the lumbar spine, and the femur were increased in the lumbar spine, the lumbar spine, the femur, and the femur. In the post-analysis results, changes in body composition were statistically significant due to decrease in muscle mass, body weight, body fat mass and BMI after combined exercise. In the change of bone density, lumbar spine BMD was measured as lumbar spine 1, lumbar spine 2, lumbar spine 3, And the femur density was increase.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.671-677
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• 2017

In this study, scattering factors affecting the quality of medical images were quantitatively analyzed and investigated. MCNPX simulation was conducted by using ANSI phantom, made of tissue equivalent materials, to calculate the scattering ratio occurred by the increase of the object thickness. Then, the result of the simulation was compared with the result of actual radiation measurement. In addition, we evaluated the image quality by the RMS evaluation, RSD and NPS analysis using X-ray images acquired with increasing object thickness. Furthermore, the scattering ratio was analyzed by increasing the thickness of acrylic phantom on chest phantom. The result showed that the scattering ratio was increased to 57.2%, 62.4%, and 66.8% from 48.9%, respectively, when the acrylic phantom thickness was increased by 1 inch from 6.1 inches. The results of MCNPX simulation and the actual measured scattering dose showed similar results. Also, as a result of RMS measurement from acquired x-ray images, the standard deviation decreased as the object thickness increased. However, in the RSD analysis considering the average incident dose, the results were increased from 0.028 to 0.039, 0.051, 0.062 as the acrylic phantom thickness was increased from 6.1 inches to 7.1 inch, 8.1 inch, and 9.1 inch, respectively. It can be seen that the increase of the scattering effect due to the increase of the object thickness reduces the SNR. Also, the NPS results obtained by measuring scattered radiation incident on the detector resulted in the increase of the noise as the object thickness increased.

• Radiation Oncology Journal
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• v.7 no.1
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• pp.59-70
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• 1989

Cervix cancer is the most common female cancer in Korea. In spite of their relatively local invasive tendency, still $44\%$ of patient will develop recurrent cancer. This result suggests that more aggressive local treatment may increase the cure rate but increased complication risk also cannot be avoidable. Various institutions proposed different treatment regimen, but recommended dose were about 4500 cGy for whole pelvis and 8000 cGy at point A, even though they agreed that those doses may not be satisfactory for control of bulky disease. 96 cases of invasive cervical cancer, treated with postoperative or primary radiation therapy were analyzed to determine the complication rate and prognostic factor in our treatment regimen Which is $5500\~1000 CGy$ higher than Other institution. Mean follow up duration was 21 months. Symptomatic patients including mild but persistent abdominal discomfort was $46\%$, but only 1 patient $(1\%)$ had operative treatment because of incomplete obstruction of small bowel. Most symptoms appeared within 12 months and most common complaints were frequent bowel movement. Barium enema and sigmoidoscopy were performed for persistent symptomatic patients. Only one patient had abnormal finding in barium enema which showed inefficiency of this method for detecting bowel complication. Patient's age, total tumor dose, total TDF, rectal dose were not significant risk factors for complication, but boost dose, previous history of operation had some relationship with complication risk. Even though dose of point A and rectum is $500\~1,000cGy$ higher than other institution, such a low rate of severe complications may suggest that fear of complications should not be overestimated than cure rate and the possibility of more aggressive treatment for better local control should not be underestimated.