투시장치의 화질관리 실태 조사

이성길,김영근,김창복 광주보건대학 2004 論文集 Vol.29 No.-

It is important to control resolution for maintenance of good image quality in fluoroscopic unit. This study is to analyze current situation on control of image quality in fluoroscopic unit. Between the sixth and the twenty eighth March 2003, 77 fluoroscopic units in 40 hospitals in Seoul and Kyung-gi area were tested with fluoroscopic phantom(CDRH phantom, Nuclear associates, USA) and image quality test tool including hight contrast resolution patterns and low contrast objects. We exposed radiation in condition of colon study, and then counted the number of patterns on monitor, printed spot film, and printed abdominal film. In the test on monitor, suitable unit within standard number in hight contrast and low contrast test were 68(88%), 49(64%), respectively, and in the test on printed spot film 73(95%), 67(87%), respectively. The cases within standard number in hight contrast and low contrast test on all the two monitor and printed spot film were 44(57%), 65(84%), respectively. Thradiation was exposed from 100 to 120Kvp in fluoroscopy, and spot radiography 80 to 110Kvp mainly. In conclusion, it is necessary that image quality control is done continuously by standard of image quality control suitable for current situation.

LC 공진형 PWM 인버터를 이용한 X선 발생장치의 특성에 관한 연구

이성길,박수강,임홍우,조금배,백형래,임양수 조선대학교 에너지.자원신기술연구소 2002 에너지·자원신기술연구소 논문지 Vol.24 No.1

The conventional types of X-ray generators were bulky in physical size and heavy in weight, and the control accuracies of the output voltages were not always satisfactory. The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing power semiconductor devices. In this paper, the newly developed converter to take the balance of the output voltage versus the ground are also presented in detail to decreasing the volume and the weight of high voltage transformer and to stabilize ripple. This converter consists of the two independent L-C series resonant circuits using the two capacitances and the two primary windings of high voltage transformer.

펄스폭 변조에 의한 무정전 전원장치에 관한 연구

이성길,박해암 광주보건대학 1989 論文集 Vol.14 No.-

Recently Uninterruptible Power Supply (UPS) Systems are widely used in a variety of fields a s highily reliable power sources. This paper presents the operation and performance of an UPS using sinusoidal Pulse Width Modulation <PWM> techniques. By using the sinusoidal PWM method for UPS systems, the property of harmonics, efficiency and distortion can be improved. Experimental results showed that sinusoidal PWM techniques have good features for UPS system.

X-선관 지지장치의 형태에 따른 광조사야와 X-선 조사야 차이가 영상의 왜곡에 미치는 영향에 관한 연구

이성길,김영근 광주보건대학 1993 論文集 Vol.18 No.-

The centering error and the difference of X-ray and light field are investigated to the effect of image distortion with X-ray equipment at the hospitals and clinics in Kwang ju. The conclusion is that: 1. The centering error of standing type is investigated more highly than the ceiling type. (p<0.05) 2. The error of centering beam is induced the distortion of image in the skull lateral projection. 3. The regular calibration in X-lay equipment is absolutely necessary for image quality control.

Cassette-증감지계 사용실태에 관한 연구

이성길,김영근 광주보건대학 1994 論文集 Vol.19 No.-

The intensifying screen speed and contact test are investigated with cassette-intensifying screen using the hospital and clinics in Kwangju. The results are as follows; 1. The using intensifying screen speed are extremely different each other. 2. The using intensifying screen are most H.S.(91%) 3. The most of using intensifying screen are not clear in period of using (H.S:54%,M.S:62%) 4. The film-screen contact functions are inferior as increase in size.

Digital Subtraction Angiography (DSA)시 Grid 사용유무에 따른 화상변화에 관한 연구

이성길,김승국,김영근 광주보건대학 1990 論文集 Vol.15 No.-

It has been investigated the variation of the image for using and no using the Grid at the D.S.A(Digital Subtraction Angiography) system. The result of experiment indicated that in the case of no using the Grid, (1) the irradiation dose of patient was reduced and the life of X-ray tube prolonged. (2) the variation of the contrast was not influence of using the Grid.

인버터식 X-선장치의 맥동률에 따른 출력특성 연구

이성길,백형래 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.1

This paper deals with the output characteristics of resonant PWM inverter type X-ray generators connected to different DC power units i.e, a single phase full bridge rectifier. a three phase full bridge rectifier and a power storage unit(PSU). The quality of X-ray beam depends on the pulsating waveforms of DC voltage supplied to the X-ray tube. In a X-ray generator, the waveform of DC output voltage can be affected from harmonic distortion of DC input power. When a tube voltage waveform is distorted, the property of X-ray beam such as reproducibility, linearity and dose can be reduced. Therefore, this paper compared DC output waveforms and dose with three type of DC power units and show the experimental results in this paper.

고주파 공진형 인버터식 X선발생장치의 관전압 불균형 개선

이성길,김영근,박수강 광주보건대학 2000 論文集 Vol.25 No.-

In order to radiate X-ray, the low ripple stabilized high voltage DC over the range of 40kV to 150kV is directly inflicted to X-ray tube. The energy characteristics of the radiated X-ray depend on the pulsating waveforms of the DC voltage supplied X -ray tube. In general, the low ripple voltage waveforms with fast rising times are required to increase with the dosage per unit time lest the exposure time should be longer in order that the motion artifacts of an object may be eliminated in actual. The rotating anode and the cathode of the metal-envelope X-ray tube are incorporated into an envelope made of metal, for instance stainless steel and copper, instead of hard glass. This metal envelope is able to collect the secondary electrons which causes harmful influence to thequality of the diagnostic images. Furthermore, the metal-envelope X-ray tube has mechanically higher strength than glass-envelope type, and so it suits for high power X-ray system. For those benefits, this type of X-ray tube is mainly used to obtain the high quality diagnostic images in X-ray angiography and X-ray computed tomography. The electrons collected at th envelope generate the eletric current flow form the ground to the cathode and occasionally the unmatched impedance of the anode side and the cathode side of the X-ray tube. The unmatched impedance causes the remarkable imblacne of the output voltage of the series resonant inverter-fed converter. In this paper, the newly-developed converter to take the balance of the output voltage versus the ground are also presented in detail. This converter consists of the two independent series resonant circuit using the two capacitance and the two parimary winding high-voltage transformer.

단상유도전동기의 부하적응형 위상제어시스템 설계

이성길,김승국,박수강 광주보건대학 2003 論文集 Vol.28 No.-

The three-phase induction motor is rugged, reliable, long-lived, self-starting, smooth-running. But it is relatively inexpensive and three-phase power in not available everywhere, so if possible we need single-phase motor with the same characteristics. In fact, single-phase induction motors have excellent characteristics and outnumber the three-phase variety. Most of the small electric motors used in home, farm, or office are single-phase induction motors of one type or another. This electric motors application field need most energy saving type drive according to enlargement of electronic goods and to tend high class. The paper is proposed a various phase control methods for energy saving of single- phase induction motor. The controllers that are embodied by each method can use by various usage according to each performance and it is considered that application may help in the electrical energy saving because is possible to other electrical appliances.

PWM 인버터를 이용한 단상유도전동기의 보조권선제어

이성길,김영근,박수강 광주보건대학 2002 論文集 Vol.27 No.-

In this paper, an auxiliary winding driving system of single - phase induction motors is described. Starting time variations are obtained by controlling the auxiliary winding voltage magnitude and phase angle, while the motor's main winding is directly connected to the local utility. A variable auxiliary winding voltage phase angle is shown to yield significant torque control, providing starting and braking torque. The analysis includes the determination of the relationship between the auxiliary winding voltage phase angle and the phase angle difference between the main and auxiliary winding current. The paper proposed for adjusting an auxiliary winding voltage magnitude and phase angle. Experimental results of motor's starting characteristics with using the PWM inverter for auxiliary winding power supply are shown. The drive is tested using a dynamometer to experimentally verify the results of the theory.