The Cobey method and the modified Cobey method are most commonly used in clinical practice. Therefore, the purpose of this study was to investigate the radiological differences between Cobey and modified Cobey and provide radiographic information about changes of hindfoot image with X-ray entrance center and tube angle change in modified Cobey. This study was performed on foot and ankle phantom. First, for image comparison of Cobey and modified Cobey, the images obtained by applying the same X-ray entrance center to the ankle joint were compared and analyzed. Second, in the modified Cobey, the X-ray entrance center is set as ankle joint and lateral malleolus. The X-ray tube angle was varied from $10^{\circ}$ to $40^{\circ}$ at $5^{\circ}$ intervals for each X-ray entrance center. The images obtained by varying the X-ray tube angle from $10^{\circ}$ to $40^{\circ}$ at intervals of $5^{\circ}$ for each X-ray entrance center were compared and analyzed. The irradiation conditions were the same with 110 kVp, 200 mA, 10 ms, and 110 cm of source - image receptor distance (SID). Image evaluation was performed by two radiologists. Measurements were made on the lateral point, middle point, and calcaneus width based on a hypothetical line parallel to the calcaneal tuberosity. Data were analyzed by using descriptive statistics as the mean of the distance to each measurement location. The modified Cobey was longer than the Cobey by an average of 3 to 4 mm lateral and medial points, and the calcaneus width was similar (ICC = 0.939). In modified Cobey method, when the X-ray entrance center is ankle joint, the lateral point is about 3 mm and the medial point is about 4.3 mm longer than lateral malleolus. Also, when the X-ray tube angle is more than $20^{\circ}$, the degree of distortion is large. The ICCs for the lateral, medial point, and calcaneus width were 0.998, 0.961, and 0.997, respectively, as the X-ray entrance center and tube angle were changed. There was no significant difference between Modified Cobey and Cobey. Modified Cobey showed no need to compensate the $20^{\circ}$ detector angle of the Cobey. In addition, we suggest that tube angle should be limited within $20^{\circ}$ when modified Cobey is performed.

In this study, we have researched the effectiveness of silicone pad. A distribution of scatter ray in mammography was evaluated using Monte-Carlo (MC) simulation technique and then a silicone pad was applied to remove the scatter ray for improving image quality. Molybdenum target and Molybdenum filter combination made a difference of 59.8% to a number of photon at 17.5 keV. On the other hand, Tungsten target and Rhodium filter showed a variation of 24.5% at 20 keV. Mean 68 of SNR was increased in Selenia and mean 1.04 of SNR was raised in Senographe. Silicone pad was significantly effective to reduce the scatter ray that was generated by primary X-ray. It can decrease an absorption rate of scatter ray to patient body and whilst it improve the image quality from increasing SNR.

Transarterial chemoembolization is one of the most representative procedures for puncture of the femoral artery. In addition, the same procedure is often repeatedly performed many times, and Hepatocellular carcinoma patients due to cancer is significantly lowered blood tests, regardless of platelet counts are not good enough to stop bleeding. More importantly, hepatocellular carcinoma has a high degree of complication and disease severity, which makes it less likely that the condition of the body will be relatively inferior to other patients. In order to prevent delayed hemorrhage of the femoral artery puncture site after the procedure, it is advised to absolutely stabilize the limb so that it does not bend the limb for 3 hours after climbing in the ward. Therefore, I have been complaining about inconvenience. In addition, in order to prevent delayed hemorrhage after hemostasis, balloon type hemostatic device was used instead of sand bag which was placed on hemostatic site. The results of this study were compared with the results of actual application. The use of a balloon-type hemostatic device to increase the effectiveness of continuous hemostasis and to minimize the inconvenience during the time of patient's absolute bed rest, rather than raising the sandbag to prevent primary delayed hemorrhage by various methods in transarterial chemoembolization. It can be used as a substitute for existing sand bags because it can alleviate pain, increase satisfaction, and can be used as a disposable one.

The purpose of this study was to evaluate the pathologic results of hepatic parenchyma parameters such as liver parenchyma, liver surface, liver margin and liver, portal vein, spleen size, And to evaluate the usefulness of fibrosis progression and hepatic ultrasonography. The sensitivity, specificity, positive predictive value, and prognostic value according to the stage of fibrosis and grade of inflammation were divided into two groups according to the morphologic variable "A" through ultrasound and "B" We evaluated the predictive value and predicted the variables to evaluate fibrosis in clinical diagnosis and treatment of patients with chronic liver disease. The sensitivity and specificity of hepatic fibrosis in hepatic morphologic variables and other size variables were highest in liver surface and edge. The morphologic parameters used in the evaluation of fibrosis were clinically relevant in distinguishing the fibrosis stage from the results of liver biopsy.

Most of the vascular procedures performed for various diagnoses and treatments of various abdominal intervention procedures performed by the Department of Radiology and Angiography are performed by puncture of the femoral artery. For this reason, patients should undergo blood-related tests such as prothrombin time (PT) and partial thromboplatin time (PTT). Therefore, many patients are instructed to take precautions such as putting a sandbag on the puncture site to prevent delayed hemorrhage after hemostasis of the femoral artery puncture site, and not to bend the leg of the treated area for about 3 hours. Because of this, many patients have complained of pain during the procedure and inconvenience during the absolute bed rest time in the ward. The purpose of this study was to compare the safety of balloon ancillary devices with sandbags placed on the hemostasis site to prevent delayed hemorrhage after arterial puncture. We compared the safety of each patient with the results of medical records in consideration of the problem that the patient could not press with the focus, the position of the patient was changed depending on the patient's body shape, and the problem of falling down according to the location of the puncture site. As a result, the use of a balloon type ancillary device improves the effect of continuous hemostasis, reduces discomfort during the patient's absolute stabilization time, increases the patient's satisfaction, and is a good alternative to the existing sandbag.

The purpose of this study was to evaluate the prevalence of thyroid nodules and malignant findings of thyroid nodules in 1,954 patients (654 males and 1,300 females) aged 20 years or older who underwent thyroid ultrasound from January 2018 to December 2018. Examination of the thyroid gland was performed, and fine needle aspiration cytology was performed on the thyroid nodule. As a result, 108 (16.5%) out of 654 males and 368 (28.3%) out of 1,300 females showed higher prevalence than males. The prevalence of single nodules and multiple nodules in gender and age groups was significantly higher for women and for ages (male p=.001, female p=.001). There was a significant difference in males in the nodule size (p=.001) and no significant difference in females (p=.069). Fine - needle aspiration cytology of 476 patients with nodules was diagnosed as malignant in 46 patients (9.6%). Based on pathologic results, 383 benign and 93 malignant groups were analyzed. Ultrasonographic findings were as follows single nodule (p=.000), solid(p=.004), hypoechoic (p=.000), ill-defined peripheral boundary (p=.000), and calcification (p=.000), respectively. In the diagnosis of thyroid nodule, primary ultrasonographic findings through morphological classification of the nodules may reduce indiscriminate fine needle aspiration cytology in benign and malignant nodules.

Comparison of the effective dose of the chest and the equivalent dose of the lens site in the radiation workers working at four medical institutions with the PET / CT room located in one metropolitan city and province from April 1 to June 30, 2018 Respectively. Radioactive medicine were measured at the time of dispensing and at the time of injection. In this experiment, the average dispensing time per patient was 5.7 minutes and the average injection time was 3.1 minutes. The equivalent dose at the lens site was $0.78{\mu}Sv/h$ for 1 mCi, and the effective dose for chest was $0.18{\mu}Sv/h$ per 1 mCi. The equivalent dose at the lens site during injection was $0.88{\mu}Sv/h$ per mCi and the effective dose of chest was $0.20{\mu}Sv/h$ per mCi. The daily effective dose of the chest was $0.9{\pm}0.6{\mu}Sv$ and the equivalent dose of the lens site was $3.6{\pm}1.4{\mu}Sv$ during daily dosing for 20 days. The effective dose of the chest during the day was $0.6{\pm}0.5{\mu}Sv$ and the equivalent dose of the lens was $2.2{\pm}1.0{\mu}Sv$. At the time of dispensing, the equivalent dose of the lens was $0.187{\pm}0.035mSv$, the effective dose of the chest was $0.137{\pm}0.055mSv$, the equivalent dose of the lens was $0.247{\pm}0.057mSv$, and the effective dose of the monthly chest was $0.187{\pm}0.021mSv$. As a result of the corresponding sample test, the equivalent dose and the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, The equivalent dose of the lens and the effective dose of the chest were statistically significant (p<0.05) with a significance of 0.000. However, there was no statistically significant difference (p>0.05) between the equivalent dose and the effective dose of the chest, the equivalent dose of the lens at the time of injection, and the effective dose of the chest at 0.138 and 0.230, respectively.

The purpose of this study is to evaluate the dose distribution by gantry rotation and MLC moving speed on treatment planning system(TPS) and linear accelerator. The dose analyzer phantom(Delta 4) was scanned by CT simulator for treatment planning. The planning target volumes(PTVs) of prostate and pancreas was prescribed 6,500 cGy, 5,000 cGy on VMAT(Volumetric Modulated Arc Therapy) by TPS while MLC speed changed. The analyzer phantom was irradiated linear accelerator using by planned parameters. Dose distribution of PTVs were evaluated by the homogeneity index, conformity index, dose volume histogram of organ at risk(rectum, bladder, spinal cord, kidney). And irradiated dose analysis were evaluated dose distribution and conformity by gamma index. The PTV dose of pancreas was 4,993 cGy during 0.1 cm/deg leaf and gantry that was the most closest prescribed dose(5,000 cGy). The dose of spinal cord, left kidney, and right kidney were accessed the lowest during 0.1 cm/deg, 1.5 cm/deg, 0.3 cm/deg. The PTV dose of prostate was 6,466 cGy during 0.1 cm/deg leaf and gantry that was the most closest prescribed dose(6,500 cGy). The dose of bladder and rectum were accessed the lowest during 0.3 cm/deg, 2.0 cm/deg. For gamma index, pancreas and prostate were analyzed the lowest error 100% at 0.8, 1.0 cm/deg and 99.6% at 0.3, 0.5 cm/deg. We should used the optimal leaf speed according to the gantry rotation if the treatment cases are performed VMAT.

In order to reduce the radiation exposure dose of the patient and to obtain accurate diagnosis results, the quality control of the diagnostic radiation generator must be conducted periodically In particular, bone density test equipment could be influenced by many factors, and it is far more important because inaccurate measurement would eventually affect the result value. However, the cross-correction phantom of DXA equipment is poorly penetrated due to lack of awareness of the industry and the high cost. Therefore, this study developed a BMD phantom using a 3D printer and Korean BMD phantom with low cost by cross analyzing Korean BMD value from The Korean National Health and Nutrition Examination Survey and evaluated it. The L1, L2, and L3 BMD values of phantoms produced with the 3D printer were measured to be $0.887{\pm}0.006g/cm^2$, $0.927{\pm}0.006g/cm^2$, and $0.960{\pm}0.005g/cm^2$, at 215 mm height and $0.882{\pm}0.011g/cm^2$, $0.914{\pm}0.005g/cm^2$, $0.933{\pm}0.008g/cm^2$ at 155 mm height displaying statistically significant relevance. The result suggests that a proper quality control and cross calibration of DXA device be possible and expected to be an essential data for various medical phantom manufacture development using 3D printer.

Medical institutions are abundant in human resources and have a unique structure with diverse professions and various organizational cultures coexist. This organizational culture influences organizational effectiveness and influences the effectiveness of the organization as a factor of leadership and organizational culture. Leadership is an important factor in linking employee behavior to organizational commitment to achieve job satisfaction. The purpose of this study was to analyze the effect of organizational effectiveness on organizational culture, leadership perception, and job stress in a special organization called radiologist. As a result, organizational culture and transformational leadership showed high correlation with 0.627. Among the organizational effectiveness variables, organizational commitment showed the highest influence with transformational leadership(${\beta}=0.284$, p<0.001), and job satisfaction was also the highest with transformational leadership (${\beta}=0.440$, p<0.001). The results showed that the expectation of transformational leadership affects organizational commitment and job satisfaction. In order to expect a positive change in the effectiveness of the organization, the radiologist culture requires an organizational culture that can fully demonstrate autonomy and creativity, and transformational leadership is required for this.