CT scan 시 X-ray tube는 환자를 중심으로 360° 회전을 하기 때문에 산란선은 모 든 방향에서 발생한다. 임상에서 환자의 피폭을 감소시키기 환자의 흉·복부 전면만을 차폐하고 환자 후면이나 측면에서 발생되는 산란선에 대한 차폐는 시행하고 있지 않 다. 두부(Brain) CT 검사 시 흉부 및 복부에 입사되는 산란선을 ion chamber로 측정 하여 그 분포를 확인하고 두부 CT 검사 시 발생되는 산란선의 분포를 통해 기존 차폐 방법의 적정성을 평가 하고자 한다. 연구결과 gantry angle이 클수록, 전면보다 후면에 서 산란선이 많이 발생했다. 두부 CT 검사 시 발생되는 산란선에 의한 피폭을 최소화 하기 위해 가급적 gantry angle을 작게 줄 수 있도록 환자 두부의 위치를 조정하여 검 사를 하거나 납치마를 이용하여 환자의 흉·복부를 차폐할 경우 전면 뿐 아니라 양 측 면과 후면을 납치마를 이용하여 차폐를 해야 할 것이다.

When using the original Angio Intervention, one had to put Guide wire, Catheter on patient's leg so that there were curves according to patients and the possibility of patients moving made it inconvenient to proceed. Thus, by making supplementary tool shaped of table, it minimized the inconvenience of patients and operator, increasing the convenience of the process and thereby evaluating the utility and its usefulness. The main material of supplementary tool was used with cost efficient Fomax material, and by considering the patient's lower limb, and the length of tools when doing Angio Intervention, it was made as 1300mm, 600mm at the front, 500mm at the back. Also, considering the weight of the tool, it was manufactured with thickness of 5mm and 10mm with the same design, and evaluated by using survey of 14 medical personnel using the tool in A University Hospital, Daejeon. When manufacturing and using supplementary tool, it became heavier as the thickness increased. Whereas, the thinner, the lighter the tools were, however, had unstability which cause lack of safety. Despite the fact, they responded that they had more convenience of using 5mm and 10mm tool compared to when they did not have at all, and through this, we could evaluate that the use of supplementary tool is useful to the procedure. Accordingly, when doing Angio Intervention, we could find out that it is useful to use the supplementary tools, and by reducing the weight and increasing the safety, if we can make use of this kind of supplementary tools, it would be more useful to the procedure.

Because the lens is a tissue with the highest sensitivity, the lens shielding is very important in CT imaging. However, in clinical terms, there is a lack in the efforts in decreasing dosage on the lens, and the shielding of dosage and the effects on the imaging are researched using bismuth to evaluate the usefulness. As results of the dosage evaluation results, when there is no gantry angle when the thickness of the lens shielding material is 0mm, the dosage was 28.476mGy, and when there is gantry angle, the dosage was 20.852mGy that it was confirmed that the dosage was 27% lesser with gantry angle. It was confirmed that the dosage value decreased with the increase of thickness of lens shielding material when there is gantry angle, and when the lens shielding material was 1mm, the dosage decreased by approximately 39% compared to when it was 0mm. When there is gantry angle, the dosage values were respectively 12.788mGy and 12.776mGy for the crystalline lens shielding material thicknesses of 0.75mm and 1.0mm. In image analysis, the quantitative evaluation and the qualitative evaluation were almost constant regardless of the thickness of the lens shielding material. The optimal lens shielding material thickness to minimize the does of lens and increase the value of diagnosis in Brain CT examination is 0.75mm. Therefore, if this is utilized for easier use in clinical practices, it is considered to be able to contribute to not only the protection of the lens but the accurate diagnosis of diseases.

The number of CT gradually tends to increase, but radiation exposure includes higher exposure dose of patients than other test methods as the rate of 67% in the whole radiology tests. Exposure dose of patients has increased due to it and the second exposure has been done by scattered rays of other organs except for test sites. Especially, special shielding has not been done in gonad which is very sensitive to radiation in brain and chest CT. So this study tries to research the second exposure dose of the gonad and how to shield it in Chest CT which does not include it. It was intended for 20 male adults who are 30 years old and conduct chest CT. SIEMENS’s SOMATOM DEFINITION AS* was used as CT equipment. For the scanning conditions, The tube voltage is 120kv, the tube current is 90mAs, and the slice thickness is 3mm as the general chest CT conditions. CHIYODA TECHNOL CORPORATION’s FGD1000 was used as Glass dosimeter (PLD). A lead pad of 0.25mmPb was produced as the shielding board. For the research method, the shielding rate was compared by measuring exposure dose of the gonad before and after shielding and the usefulness of the shielding board was evaluated. The average exposure dose of symphysis pubica before shielding was 280.5μGy and the average exposure dose of coccyx was measured as 151.5μGy. The average exposure dose of symphysis pubica after shielding the gonad with a lead pad of 0.25mmPb was 42μGy and the average exposure dose of coccyx was measured as 41μGy.

We performed the quantitative analysis using MATLAB for slice thickness, spatial resolution, and low contrast resolution with the 50 received images which have suitable judgement by scanning AAPM phantom using GE, PHILIPS, SIEMENS, and TOSHIBA. Slice thickness and spatial resolution were measured by using full width at half maximum(below FWHM). Spatial resolution was confirmed that FWHM interval more than 1.0 mm size. Low contrast resolution was measured that how close by using Roundness Index(below RI) until 6.4 mm size. The spatial resolution 9 images and low contrast resolution 10 images which have disapproved judgement were also had the quantitative analysis. The statistic analysis was judged to have statistically significant differences when p-value is less than 0.05 through SPSS statistics 19.0 and T-test (paired t-test). For slice thickness 5 mm, the average qualitative evaluation group shows 4.98 mm and quantitative evaluation group shows 5.02. For slice thickness 10 mm, the average qualitative evaluation group shows 9.98 mm and quantitative evaluation group shows 9.86. No significant differences (p=0.07, p=0.06) with 5 mm and 10 mm. It confirmed the interval for all FWHM until 1.75, 1.50, 1.25, 1.00 mm as approved images on spatial resolution ,and the average distance was 0.102 mm and the minimum distance 0.054 mm. For disapproved images, all interval was not showed under 1.00 mm. For low contrast resolution, spproved image’s RI value shows average 0.81 and minimum 0.77. The disapproved image’s RI average shows 0.70. Statiscally significant differences were presented (all p<0.05) following hole size.

The study was conducted from July 5th to 12th, 2014 on 30 males and females. The examination device used for this study were Discovery XR656(GE Healthcare, Kemath, Germany) DR and SOMATOM definition AS+ CT. T he device was made of foamex (foam PVC). The posture for cubital tunnel view examination requires for patients to bend their elbows more than 60 degrees and turn their forearms 20 degrees externally. The analysis method of cubital tunnel depth(CTD) was to measure the length between the deepest location of groove for ulnar nerve and a line vertical to the line connecting protruding part of medial epicondyle and trochlea medial in order to measure the CTD with and without the assistance device. CTD were measured and compared from VRT images on CT examination of 30 males and females to prove the usability of the assistance device. For statistics, SPSS 18.0 version was used to conduct independent two samples t-test. Differences in CTD between the two sexes were nonexistent but, the differences in CTD according to the use of assistance device were 4.63±0.86mm in temporizing measure, and 6.01±0.27mm with the assistance device for male. For females, the results were 4.58±0.41mm in temporizing measure and 5.94±0.58mm with the assistance device. The results proved that the measured values of CTD are deeper with the use of assistance device. The difference between CTD value from CT of normal person and CTD level measured with X-ray using the assistance device were nonexistent. P<0.05) Use of an assistance device made more accurate and convenient examinations possible compared to examinations without any assistance devices. Use of the assistance device in this study in radiological examinations on Cubital Tunnel Syndrome would provide more accurate and convenient examinations in the future. Keyword : Cubital Tunnel

In this study, mammography was conducted with Lorad Selenia from HOLOGIC. The phantoms used were Female rando phantom from THE PHANTOM LABORATORY and ACR phantom from GAMMEX RMI. The dosimeters used were the glass dosimeter reader FDG1000 and PLD from CHIYODA TECHNOL. The shielding used to compare and determine the amount of scattered ray in this study were lead shielding gear with a thickness of 0.25mm from INFAB and a customized bismuth shielding with a thickness of 0.2mm(2 layers of 0.1mm). The conditions were 28kVp, 65mAs for CC view and 30kVp, 85mAs for MLO view. The exposure dose by scattered ray were measured from thyroid, breast on the opposite side and gonad (hereafter called critical organs) without any shieldings for the first experiment, then measured four times each with lead shielding for the next experiment, and measured four times each with bismuth shielding for the third experiment. The average dose for each critical organ without shieldings were 135.75μGy, 649.67μGy and 546.25μGy, With lead shielding, the numbers were 0μGy, 63μGy and 1.5μGy, and 6.25μGy, 12.25μGy and 26.5μGy with bismuth shielding. Therefore, the lead and bismuth shielding have reduced 95.364% and 93.550% of exposure dose. Use of shielding s during mammography reduces the exposure dose on critical organs and other organs of the patient, and despite the similar shielding rate, the new shielding using bismuth is useful in shielding thyroid and gonad considering the mobility of the patient, light weight and thickness of the shielding.