Film Cassette의 세균 오염도와 소독에 관한 연구

권대철,정경모 최지원 대한방사선과학회(구 대한방사선기술학회) 2000 방사선기술과학 Vol.23 No.2

AN IV CATHETER FRAGMENTS DURING MDCT SCANNING OF HUMAN ERROR: EXPERIMENTAL AND REPRODUCIBLE MICROSCOPIC MAGNIFICATION ANALYSIS

권대철,이종웅,최지원,양성환,동경래,정운관 대한방사선방어학회 2011 방사선방어학회지 Vol.36 No.4

The use of intravenous catheters are occasionally complicated by intravascular fragments and swelling of the catheter fragments. We present a patient in whom an intravenous catheter fragments was retrieved from the dorsal metacarpal vein following its incidental CT examination detection. The case of demonstrates the utility of microscopy and multi‐detector CT in localizing small of subtle intravenous catheter fragments as a human error. A case of IV catheter fragments in the metacarpal vein, in which reproducible and microscopy data allowed complete localization of a missing fragments and guided surgery with respect to the optimal incision site for fragments removal. These reproducible studies may help to determine the best course of action and treatment for the patient who presents with such a case.

Comparison of the Measured Stem Leakage Correction Factor for an Ionization Chamber in Air to the Monte Carlo Simulation

권대철,이재승,구은회,김문집,정재은,정운관,동경래,이진국,박철우,임인철 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.5

Stem leakage arises as a consequence of the direct irradiation of a sensitive volume, and the metal stem of the ionization chamber, and the chamber response is likely to be affected by the photons scattered from the chamber stem. These interactions contribute to the apparent measured exposure. Build-up caps were used in the exposure measurement. The stem leakages of PTW model TM 30013 and TM 31010 (vented to air, sensitive volume: 0.6 and 0.125 cm^3) ionization chambers were measured. High-energy photons generated by a linear accelerator and the sensitive volume of the ionization chamber were measured to examine the stem leakage of the ionization chamber and were compared with the results of a Monte Carlo simulation. As a result, the electrons ejected from the metal stem could were found to collect at the central electrode. The stem leakage correction factor (k_(stem,leak)) decreased with increasing photon energy and sensitive volume. The stem of the ionization chamber that scattered photons made the largest contribution to the exposure dose, showing a dependency on the energy of photons and the sensitive volume of the ionization chamber. The stem leakage correction factors were determined within 0.4% according to the length of the stem exposed in repeated measurements for various radiation fields.

Measurement of Image Quality in CT Images Reconstructed with Different Kernels

권대철,장근조,이종웅,최지원,구은회,동경래,이재승,진계환,Sungbo Seo 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.2

This study measured the image quality obtained with different scanning and reconstruction kernels for computed tomography (CT) and sought methods for visualizing the abdominal and the bar phantoms. Our objective was to evaluate the image quality of spatial domain filtering as an alternative to additional image reconstruction using different kernels in CT. CT images were obtained using a 16-multidetector CT (MDCT) scanner and were reconstructed with various reconstruction kernels. Kernels were grouped as abdominal kernels. Image data sets were reconstructed using a very smooth (B10), smooth (B20), medium smooth (B30), medium (B40), medium sharp (B50), sharp (B60), very sharp (B70), and dedicated, ultra-sharp (B80) reconstruction kernel. The B20 and the B30 kernels provided better peak signal-to-noise ratio (PSNR), less root mean square error (RMSE), maximum absolute error (MAE), and reconstructed convolution kernels comparable to other kernels used as reconstruction kernels. The increase in the diagnostic accuracy of CT images obtained using the abdominal B20 and B30 kernels may be controlled by adjusting the various CT algorithms, to take into account the kernels of the CT algorithm undergoing the examination.

잡견에서 조영제 혈관외유출 예방을 위한 스트레인 게이지 기반의 EDA 시스템 성능 평가를 위한 실험적 연구

권대철,유병규,이종석,조문선,양성환,Kweon, D.C.,Yoo, B.G.,Lee, J.S.,Cho, M.S.,Yang, S.H. 대한의용생체공학회 2008 의공학회지 Vol.29 No.1

The major risk associated with the use of automated power injectors is the well known complication of contrast material extravasation at the injection site. Automated injection of computed tomography (CT) contrast media can produce the compartment syndrome. The purpose of this study was to assess the ability of this device during clinically important episodes of extravasation. The extravasation detection accessory (EDA) system was composed of a strain gage, an amplifier and a computer based system. A strain gage pliable adhesive patch was applied to the skin aver the intravenous catheter and the catheter was connected to the power injector with a cable to monitor the resolution data. If the programmed monitoring, which was developed with MS Visual C++, at the extravasation occurred, then the injection was interrupted the auto injector. CT was used to demonstrate the clinically important extravasation. This study was a prospective, observational study in which the EDA system was used to monitor the automated mechanical injection of contrast material in 7 dogs. There were two true-positive cases (range of extravasation volumes: $18{\sim}22ml$), twenty three true-negative cases, three false-positive cases and no false-negative cases. The EDA system had a sensitivity of 100% and a specificity of 88% for the detection of clinically important extravasation. The EDA system had good sensitivity for the detection of clinically important extravasation and the EDA system has the clinical potential for the early detection of extravasation of the contrast medium that is administered with power injectors. The EDA system is easy to use safe and accurate for the monitoring extravasation of the intravenous injections, and this system may prove especially useful in CT applications.

23) X-RAY 이동 촬영시 간호사의 방사선 피폭인식도에 관한 조사

권대철,권이선,정광수,홍미혜,정경모,박홍전,Kweon Dae Cheol,Kwon Lee Seon,Chung Kwang Soo,Hong Mi Hye,Chung Kyung Mo,Park Hong Jun 대한방사선사협회 1999 대한방사선사협회지 Vol.25 No.1

CTDI 팬텀을 이용한 CT 검사에서Bolus Tracking Technique의 선량 평가

권대철,최지원 (사)한국방사선산업학회 2019 방사선산업학회지 Vol.13 No.3

The purpose of this study is to measure the dose using head and body CTDI phantom,and the bolus tracking technique according to monitoring for CT study. CT-dose-index (CTDI)phantoms of the head and body were used to measure dose in CT using the bolus trackingtechnique. Scout scans were applied with a tube voltage of 120 kVp and a tube current of 30 mAsin the head and CTDI body phantom. Bolus tracking technique scanning was performed at 20mAs for monitoring and 0.5 sec, B30f (medium smooth) kernel and 2.0 mm thickness. For dosemeasurement, the dose including scout monitoring was measured five times using an ionizationchamber (UNFORS Xi, Raysafe AB, Billda, Sweden) dosimeter in the center of the head and bodyphantom. The effective dose was 0.018 mSv for the head phantom multiplied by k (conversioncoefficients) by DLP and 0.066 mSv for the body phantom. Even if the radiation dose frommonitoring is low, it can be applied as a basic data effectively to reduce the dose from monitoringin the clinical trial for patients.

診斷放射線科의 쾌적환경을 위한 연구

권대철,전용웅,김길동,조암 동국대학교 산업기술연구원 1999 산업기술논문집 Vol.14 No.-

본 연구는 종합병원 진단방사선과의 환경인자 개선을 위한 쾌적환경에 관한 연구이다. 이를 위하여 진단방사선과의 주요환경이자인 소음, 조도, 색체, 온도, 습도, 총부유분진, 악취, 환기 등의 환경인자 측정이 이루어졌다. 환경인자에 대한 환자와 직원을 비교한 결과, 환자는 불만족, 직원은 대체로 만족한다고 비교되었다. 그리고 환경인자에서 낮은 수치를 보인 병원은 S병원이고, 본 병원과 C병원이 비슷하였다. This study is about the comfort environment for improving the environmental factors in diagnostic radiology of general hospital. To see, to investigate the major environmental factors of noise, illumination, color, thermal factor, humidity, TSP(Total Suspended Particulate), odor, IAQ(In Air Quality), the field measurement were conducted. The results of the comparison of patients with employees in diagnostic radiology showed that the major comfort satisfaction which have patients was dissatisfied, employees was satisfied of diagnostic radiology in environmental factors. And a comparison of environmental factors in a study hospital same as C hospital and S hospital is lower level standards.

진단방사선과 검사실의 환경개선이 환자에게 미치는 영향에 관한 연구

권대철,홍성만,김동성,박범 한국의료QA학회 2002 한국의료질향상학회지 Vol.9 No.1

Background : This study was attempted to provide us with basic data on how to environmental improvement with patients for examination, and to offer them better treatment. This study was performed to compare the patients, perception between before and after improvement in the diagnostic radiography room. Methods : The data was collected by interviewing 75 patients who underwent the radiography under the diagnostic radiology at Seoul National University Hospital in Korea. The interview ran from August 9 to October 18, 1999. Data were analyzed by percentage and paired t0test. SD(Semantic Differential)method was composed of adjective 13 words. Results : Patients were attending the elementary schools in the Seoul residents. There was no significant difference in kindness·unkindness dimension and were significant differences in other dimensions. The mean score of response level to present room was 3.67 and that of improvement room was 2.16. Conclusions : The results of this study suggest a radiography room plan which is considering emotional aspect of children.

대퇴골 전염각 측정을 위한 수 작업 방법과 Image Viewer 방법과의 비교 연구

권대철,박범,Gwon, Dae-Cheol,Park, Beom 대한인간공학회 2001 大韓人間工學會誌 Vol.20 No.3

The measurement of the fermoral anteversion is an important factor in the practice of orthopedic surgery. The anteversion is measured by means of the axis of head and neck of the femur. In this study. widely used computed tomography method of measuring anteversion was tested on femoral necks of patients. Measurement by the manual method and image viewer of computed tomography to determine the anteversion of femoral head were carried out on both femurs. In January and February 2001, 30 patients 3 to 6 years of age were randomly selected from Seoul National University Hospital. the purpose of this paper was to introduce a new method to measure femoral anteversion angle utilizing image viewer program. This new method was more accurate and convenient than the conventional manual method. No significant difference was observed between the manual method and the image viewer measurement of femoral anteversion. In conclusion, image viewer program was statistically more reliable in determining the angle of the fermoral anteversion.