Cheong-Hwan Lim

Effect of Organizational Culture and Self-leadership on Organizational Effectiveness in Radio-technologist

This study was to investigate the level of oragnizational culture and self-leadership on organizational effectiveness and the significant factors influencing organizational effectiveness in radio-technologists. The dominant organizational culture was innovation oriented culture. The mean score of self-readership score was 3.35 out of a maximum 5 points. organizational commitment was statistically significant with age, place of work, relational culture, hierarchial culture, self-goal establishmental leader ships. job satisfaction was statistically significant with marital status, realational culture, self reward leaderships, self-goal establismental lederships. these results suggest that further development should be continued to develop the effective self-readership and organizational culture to improve the organizational effectiveness of radio technologists.

Microvascular Contrast Image in Portal Veins of Rat using Micro-CT

The study focuses on the value of Micro CT, a high resolution X-ray imaging device, by using it on rats to observe the overall portal vein image of the liver and the microvasculature of each lobes, visualize the 4 segmental lobes and acquire 3D image of the microvasculature through the reconstruction of sectional image data. Less of the damage to liver of the 5 mice, the device was able to separate the liver into 4 segmental lobes and displayed the 4 portal vein microvasculature in 2D. By using the 3D MIP technique, observation of the whole portal vein system microvasculature in 3D image was made possible along with each of the portal vein segment`s branches until the 6th branch. Measured the size of 6branch, the average was measured at 1branch : , 2 branch : , 3 branch : , 4 branch : , 5 branch : , 6 branch : . The 3D image and the images of the microvasculatures in the result of study proved that the Micro-CT can be considered many useful device in obtaining high resolution images.

Comparison Measurement Error of T-score Between Lumbar and Femoral Neck According to Kind of DXA

In this study, three different devices, Norland, Osteocore and Lunar were used to compare and analyze the measurement error by each bone density measurement device by classifying the physical characteristics into age, height and weight, the subject of total 300 sampling 100 persons for each device. Categorizing Lumbar region and Femoral neck as normal (T-score-1.0), osteopenia (-1.0>T-score>-2.5) and osteoporosis (T-score-2.5), the findings were observed as follows. Norland device showed the least measurement error in age and height, while Lunar showed the least in weight among the devices. And, the result of comparing the bone density measurement error based on the lumbar region showed that all of Lunar, Norland and Osteocore have the least variation of measurement error in osteopenia and the result of comparing based on the femoral neck showed that all of Lunar, Norland and Osteocore have the least variation of measurement error in osteoporosis. For each variable, the measurement error was observed to be vary upon the device. To solve this, standardized common Phantom should be used to compare and converge the measured value of each company and cross-calibration would be necessary when replacing the software.

The Study On Quality Control of Magnetic Resonance Imaging System

The quality control is needed to ensure the accuracy of medical information and achieved by evaluating the performance of and maintaining the system and practicing various measurements and evaluations. The Korean Institute for Accreditation of Medical Image, therefore, have held educational program for quality control of special medical equipments. The major of programs participants, however, are radiology specialists with only small number of radiological technologists from some hospitals, furthermore, the follow-up education and the share of information between participants and non-participants are insufficient in general, thus, the knowledge level of radiological technologists, regardless of their participation, is relatively low. This study carried out the questionnaire research for the 500 radiological technologists registered in Korean Society of MRI Technology, on the basis of 2008, and performed analysis for five months from May to Oct., 2008. The questionnaires were delivered by post to each radiological technologists and the response rate was 36%(n

Evaluating lead thickness for Shielding during Computed tomography using Monte Carlo Simulation

The objective of this study was to determine the appropriate thickness of lead shielding for computerized tomography (CT) and mock estimate the transmission spectrum according to changes in lead thickness based on computational simulation of CT apparatus. Based on the technical manual of the CT equipment company, CT device configuration was simulated with Monte Carlo simulation code. As shielding material for CT, lead, the most used one, was selected. Lead thickness was simulated by setting it from 0 (absence of shielding material) to 1.25 mm. With increasing lead thickness, the probability of photon absorption was increased while transmittance was estimated to be reduced. In addition, photon permeability was estimated to be 50% or less with lead thickness of 0.05 mm. However, photon absorption probability was estimated to be 90% or more with lead thickness of 0.375 mm with 10%. In computational simulation transmittance experiment of computed tomography using Monte Carlo simulated code, the appropriate lead thickness of the shield was found to be 0.5 mm.

A Study on the Thyroid Dose High-Energy Radiation Therapy of Lung Cancer

고에너지 의료용 선형가속기를 이용한 폐암 방사선치료 시 갑상선에 미치는 선량을 광자극발광선량계 (OSLD)를 이용하여 평가하였다. 산란광자의 영향은 3D-CRT의 경우 25.4 mSv, 28.8 mSv, 31.3 mSv, 26.5 mSv, 27.4 mSv로 5회 평균은 27.9 mSv, IMRT에 있어서는 46.8 mSv, 43.2 mSv, 42.3 mSv, 41.5 mSv, 44.1 mSv로 5회 평균은 43.6 mSv의 결과 값을 보였다. 광중성자 선량 평가 결과는 3D-CRT의 경우 3 mSv, 3 mSv, 3.4 mSv, 3.5 mSv, 3.1 mSv로 5회 평균은 3.2 mSv, IMRT에 있어서는 5.1 mSv, 4.8 mSv, 4.2 mSv, 4.8 mSv, 4.9 mSv로 5회 평균은 4.7 mSv의 결과 값을 보였다. 산란광자와 광중성자 모두 3D-CRT 보다 IMRT가 높은 것으로 평가 되었다. 본 연구를 통하여 고에너지를 이용한 방사선치료 시 인 접한 정상조직에 상당한 양의 산란선량이 영향을 주는 것으로 평가된 바와 같이 방사선을 이용한 암 치료 종사자는 이러한 내용을 충분히 인지하여 피폭 저감화를 위한 노력이 필요할 것으로 사료된다.

A Study on the Mitigation of the Exposure Dose Applying Bolus Tracking in Brain Perfusion CT Scan

급성기 허혈성 뇌졸중 증상이 있는 뇌 관류 CT 검사를 시행한 환자를 대상으로 장비사가 제시한 고정 시간 기법(Fixed time technique)과 조영제 추적 기법(Bolus tracking technique)을 비교하여 환자의 피폭선량을 분석하고자 하였으며, 조영제 추적 기법의 유용성과 최적의 조영증강 구간을 구현하는 Time graph를 알아보기 위한 것이다. 환자에서는 PCT의

Distortion of Magnetic Resonance Imaging for Different Types of Orthodontic Material

CTDI_{VOL}

Evaluation of the Reproducibility of Radiation Output from Diagnostic X-ray Equipment(Standards Based on IEC 60601-2-54)

은 고정시간기법에서 431.72mGy, Bolus tracking에서 323.61mGy로 측정되었고, DLP값은 고정시간기법에서

Analysis of Body Mass Index on Set Up Errors Rectal Cancer in Radiotherapy

1243.47mG y{\cdot}cm