이중 에너지 검출기를 이용한 영상 시스템

여화연(Yeo, Hwa-Yeon) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.9

본 논문은 이중 에너지 DR(Digital Radiography) 방식 중, 단일 조사 X-선(single shot X-ray exposure) 장치 와 이중 모드 검출기 모듈 (Low Energy Detector & High Energy Detector)을 이용한 이중 X-선 이미징이 가능한 검 출기 모듈에 관한 연구이다. 상용 BIS(baggage inspection system)에서 사용되고 있는 X-선 발생장치의 스펙트럼과 이중 모드 검출기에 대한 특징 및 방사선적 특성을 분석하여 새롭게 제안 할 검출기 모듈의 최적 설계 방향을 기술하고 상용화된 용화된 LED 및 HED 검출기와 새롭게 제안 한 검출기 모듈에 대해 전기적, 광학적, 방사선적 특성 실험을 실시하여, 새롭게 제안 된 검출기 모듈이 BIS 용도로 사용 가능함을 증명하였다. 새롭게 제안 된 검출기 모듈이 적용된 BIS에 대해, 기본 특성 실험에 대한 X-선 영상을 획득하여 실험 및 분석을 실시하였다. Single exposure dual X-ray imaging can be used to separate soft and dense-material images for medical and industrial applications. This study keep focusing baggage inspection system(BIS) specifically. New detector modules for single exposure dual X-ray imaging are consisted of low energy detector (LED) and high energy detector (HED). First, the optimized thickness of copper filter coupled HED to separate low energy and high energy was simulated by the given X-ray energy (140 kVp, 1 mA) using Monte Carlo simulation codes, MCNPX. So as a result of simulation, the copper filter thickness is 0.7 mm. For the design of PIN photodiode, ATLAS device simulation tool was used. 16 channels PIN photodiode of 1.5 mm x 3.2 mm for Dual X-ray imaging detector was fabricated in the process of ETRI. And its dark current and quantum efficiency, terminal capacitance were measured. It was proven that the Lanex Fast B coupled HED were a sufficient candidate to replace the CsI(Tl) commerced in dual X-ray system, since these give a strong signal, overcoming system noise. Finally dual X-ray image was acquired through correction of the LED X-ray Image and the HED X-ray Image.

유방촬영팬텀을 이용한 Film-Screen 방식과 DR 방식의 영상 비교 분석

강병삼 ( Byung Sam Kang ),여화연 ( Hwa Yeon Yeo ),동경래 ( Kyung Rae Dong ) 조선대학교 공학기술연구원 2013 공학기술논문지 Vol.6 No.1

Recently, interests and utilization on Computed Radiography (CR) and Digital Radiography (DR) have tended to increase owing to an introduction of Picture Archiving and Communication System (PACS) and an accuracy control of special medical equipment for breast imaging. The present paper compared the breast image of Film-Screen methods and DR methods using the breast photographing system for accuracy of breast cancer diagnosis. We use Mammo phantom and photograph in F/S System methods and DR System methods. Each image uses the basis of assessment of evaluation tests and 10 people radiation students are visible fiber, Calcification and mass degree score. It compared the average score of each received image, then it classified the above schedule score with passing. The cellulose (fiber), the calcareous sinter (calcification)and the bell lump (mass) received a high score in DR and Film-Screen methods order. In this study, the breast image of DR methods had a better picture quality compared to the breast image of Film-Screen methods, and had received high score from all items. In DR methods, the image quality was dependent on the monitor resolution. The higher the monitor resolution, the better the quality of the image produced. According to quality control in Film- Screen methods, we found out that there was a decrease in the quality of the picture being produced.

관상동맥 조영술 및 중재술시 요골동맥과 대퇴동맥의 사용에 관한 비교연구

문일봉 ( Il Bong Moon ),여화연 ( Hwa Yeon Yeo ),임환열 ( Hwan Yeal Lim ),동경래 ( Kyung Rae Dong ) 조선대학교 공학기술연구원 2015 공학기술논문지 Vol.8 No.4

Coronary angiography and interventional study mostly use the methods of radial artery and Femoral artery. The results of 116 patients (65.% male with an average age of 63.3±11.54)who had Coronary angiography and interventional study treatments from June 12th, 2014 to September 2nd, 2014 at the Chonnam National University Hospital were analyzed. For patients who had an angiography with interventional study treatment were divided into two groups (group 1: radial artery, group 2: femoral artery) and analyzed. For the group that used the radial artery the frequency of Coronary angiography interventional study was lower (19.5% vs. 55.9%, p<0.001), and the inner radius was smaller (5.20±0.429french vs. 6.18±0.999french, p<0.001), and the amount of contrast media used was smaller (66.8±43.30cc vs. 105.7±60.30cc, p=0.001). However, there was no difference for gender, age, BMI, type of artery, radiation exposure duration and amount. In the sub-analysis, for the group that only had the Coronary angiography without the interventional study treatment and where the radial artery, the radiation exposure duration was longer than that of the group that used the femoral artery (392.30±205.263sec vs. 282.13±82.984sec, p=0.002). However, there were no differences for the other parameters. Also, for the group that had both the Coronary angiography and interventional study treatment showed no difference for all parameters. In conclusion, it can be stated that Coronary angiography that uses the radial artery and interventional study treatment, which is widely know to be comfortable for the patient and to also lower the risk for hemorrhaging, is a better and safer treatment method.

일반촬영 테이블 재질 특성에 관한 연구

김창복 ( Chang Bok Kim ),동경래 ( Kyung Rae Dong ),여화연 ( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2014 공학기술논문지 Vol.7 No.2

This study is intended to determine suitability of acryl, which has been the table material of general shooting, in line with its purpose or other available material securing better suitability than acryl among several other materials available in actual uses. Possible materials for the table used in general shooting, including acryl as the existing material, wood, plastic, glass, and pulps were compared by measuring transmittance and scattered dose by a dosimeter. Every material was prepared to have an identical thickness of 1 cm, and measurement for transmittance was conducted with fixed amperage at 100 mA while changing the voltage to 40 kVp, 60 kVp, 80 kVp, 100 kVp, and 120 kVp while measuring scattered dose for the side-scatter ray under the identical conditions excepting FFD. FFD was kept changing for the measurement. The transmittance of wood was highest when FFD was 100 cm, followed by those of acryl, pulps, plastic, and glass, and the results were identical at FFD 180 cm. As results of side-scatter ray measurements, acryl showed the highest value at FFD 30 cm, followed by wood, pulp, glass, and plastic. When considering the overall results, wood was the best material for transmittance while acryl was the best for the side-scatter ray. Though confirming the suitability of wood as the table material in consideration of transmittance and side-scatter ray was somewhat obstructive, this study could observe less level of side-scatter ray in wood than that of acryl. If only the side-scatter ray is considered, wood is the better candidate for the table material, but the properties of wood seemed to be subject for instability by serious environmental factors than others. As shown in the above, a wooden table may result in less exposure of patients to scattered ray than that of acryl, but it has a risk of degradation and consecutive infection so that the acryl is assumed to be the most suitable material for the table for general shooting in a comprehensive view among other materials.

Fat Suppression에 대한 fast spin echo fat saturation와 IDEAL - FSE 기법의 유용성 비교 연구

박용순 ( Yong Soon Park ),문일봉 ( Il Bong Moon ),동경래 ( Kyung Rae Dong ),여화연 ( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2014 공학기술논문지 Vol.7 No.1

This study is intended to implement images using fast spin echo fat saturation and IDEAL techniques as the fat suppression of reducing fat signal phase artifact caused by chemical shift phenomena on the boundary interface between water and fat, and the consecutive qualitative analysis was carried out in order to compare the availabilities of those imaging techniques. The comparison was conducted by applying the fast spin echo (FSE) T2 weighted pulse sequence and IDEAL techniques to the test. 1.5 Tesla MR scanner (Signa HDxt, GE, USA) and 16 channel CTL coil were employed in the test as the MR imaging devices. For image point, FSE technique was applied to gain images as follows: TR as 2617 / 4250 ms, TE as 85 / 110 ms, Matrix as 320 × 192 / 320 × 224, ETL as 22 / 24, FOV as 330 ㎜, and slice thickness as 40 mm. For those by IDEAL technique, the image implantation was carried out under the following conditions: TR as 4250 ms, TE as 110 ms, FOV as 330 ㎜, Slice thickness as 40, Matrix as 320 × 224, ETL as 24, Band width as 62.50 ㎐, and NEX as 2. As the qualitative analysis method, the signal to noise ratio and the contrast to noise ratio were obtained from the areas of interest in each group, and the values among each group were comparatively analyzed to determine the higher availabilities between the fast spin echo fat saturation and IDEAL-FSE techniques for the fat suppression. As results of imaging, the SNR values of fat at the given points for FSE technique were 0.933, 0.926, 0.953, and 0.956, respectively, while that for IDEAL technique was 0.97. The SNR values for water for FSE technique were 0.316, 0.233, 0.296, and 0.196, respectively while that for IDEALtechnique was 0.44. The required time for FSE technique were 1 minutes 40 seconds, 2 minutes 54 seconds, 1 minute 29 seconds, and two minutes 54 seconds while that for IDEAL technique was four minutes 28 seconds. When FSE imaging and IDEAL techniques that used the identical image points with IDEAL technique were compared among other FSE techniques, SNR of IDEAL technique was 1.017 times of that in FSE, and the time requirement was 3.011 times larger. Though IDEAL technique required 3.011 times longer time than that of FSE T2 technique, but SNR was just 1.017 time higher while CNR became 0.896 times lower. Implication by the study results may include that IDEAL technique may be used to obtain images of uniform fat suppression with excellent SNR, but FSE T2 needs to be used to promote the convenience of patients based on relatively short test time.

1.5T와 3.0T MRI에서 Saline Phantom을 이용한 자장 균일도 비교 분석

민정환 ( Jung Whan Min ),박훈희 ( Hoon Hee Park ),여화연 ( Hwa Yeon Yeo ),동경래 ( Kyung Rae Dong ) 조선대학교 공학기술연구원 2013 공학기술논문지 Vol.6 No.1

MRI generates a radio frequency (RF) pulse after setting the body in position in a large Gantry that generates a magnetic field. The signal is released by resonance of inner body``s hydrogen nucleus. This technology reorganizes and records the difference of the signal through the Computer. Recently, the use of 1.5T and 3.0T has been increased in the hospitals because 3.0T has higher Signal to noise ratio (SNR) compared to the 1.5T. To confirm the difference of magnetic field according to changes in magnetic field intensity, we used Saline Phantom. We compared SNR to magnetic field uniformity of 1.5T and 3.0T to improve the diagnostic value of image. According to size Field of view (FOV) of MRI equipment, we made a Saline Phantom ourselves. Using the Saline phantom to compare the magnetic field uniformity of 1.5T and 3.0T, we then obtained Axial and Sagittal images. According to the result of experiment, we confirmed that the numerical value of SNR using saline phantom decreased relatively as it went far away from the center of the magnetic field. In other words, a magnetic field become uneven bit by bit as it comes apart from the center. When comparing 1.5T with 3.0T, we figured out that as the intensity of a magnetic field rises, it becomes uneven. The experiment above tells us that magnetic field uniformity of MRI showed some difference depending on the location, isocenter or periphery of the magnetic field; and if the magnetic field uniformity goes off the range, distortion of the image happens. This means that even through without the complicated and highpriced equipments, it is possible to check the efficiency of MRI using simple Saline Phantom which we made by ourselves.

일반촬영장치의 정도관리 연구

강병삼 ( Byung Sam Kang ),박훈희 ( Hoon Hee Park ),동경래 ( Kyung Rae Dong ),여화연 ( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2013 공학기술논문지 Vol.6 No.4

Thanks to the rapid increase of the interest in the quality control of the General X-ray systems, this research proposes the direction of the quality control through comparing and inspecting the actual condition of the respective quality control in the Clinic, the educational institution and the hospital. The subjects of the investigation are diagnostic radiation equipment``s in the clinic, the educational institution and the hospital around the capital. A test of kVp, mR / mAs out put test and reproducibility of the exposure dose, half value layer, an accordance between the light field and the beam alignment test, and lastly reproducibility of the exposure time. Then the mean difference of the percentage, the CV (Coefficient of Variation, CV) and the attenuated curve which are respectively resulted from the above tests are computed. After that we have evaluated the values according to the regulations on the Diagnostic Radiation Equipment Safety Administration regulations. In the case of the clinic and the educational institution, there were 42 general X-ray devices. And 14.28% of the kVp test, 11.9% of the reproducibility of exposure dose test, 7.14% of the mR/mAs out put test, and 7.14% of the HVL (Half Value Layer) test appeared to be improper. In the case of the hospital, however, there were 28 devices. And 7.14% of the reproducibility of exposure dose, 7.14% of the difference in the light field/ beam alignment, and 7.14% of the reproducibility of the exposure time appeared to be improper. According to the investigation, the hospital``s quality control condition is better than the condition in the clinic and the educational institution. The quality control condition of the general X-ray devices in the clinic is unsatisfactory compared to the hospital. Thus, it is considered that realizing the importance of the quality control is necessary.

혈관조영 시 조건에 따른 시술자의 피폭선량

조동헌 ( Dong Heon Cho ),강병삼 ( Byung Sam Kang ),동경래 ( Kyung Rae Dong ),여화연 ( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2012 공학기술논문지 Vol.5 No.4

Since 1950 when Seldinger Technique was introduced, angiography equipment and medical technology have advanced. As a result of the development, there was a turning point of Angiography. Because of the increase of annual radiation dose rate to worker in angiography room, the study to reduce the rate was needed. The experimental methods using a Ion chamber, a fixed patient table and the SID(Source image distance} are changed from the fixed tube when the state of the patient tables are moving. Moreover FD(Flattering Detector) is added to adjust the filter and collimator as the used or unused method is tested. As a result of the test, the maximum rate and minimum rate are compared experimentally. The result of minimum is 116 mR/h and maximum is 1120 mR/h. the difference between the rate is 1004 mR/h which is 10 times higher than minimum rate. As a result of this study, although it is difficult to diagnosis all patients with the result dose rate, if performers use the rate, they can reduce the radiation dose.

경동맥 협착정도평가를 위한 경동맥 초음파검사의 정확도 평가

박훈희 ( Hoon Bee Park ),동경래 ( Kyung Rae Dong ),여화연 ( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2012 공학기술논문지 Vol.5 No.4

Nowadays, with the increase in the elderly population various vascular diseases are becoming more of a problem. Cerebral hemorrhage, stenosis and cerebral blocking resulted from thrombus formation in either the cardiac, or carotid artery are a number of examples which can cause cerebral infarction. In this study, carotid ultrasonography of patients with stenosis detected in both Margnetic Resonance Angiography (MRA) images and Duplex. ultrasound images are compared and analyzed by the degree of stenosis to acquire an accurate evaluation. Between October 2nd 2011, and June 2nd 2012, an investigation took place in St. Mary`s Hospital Seoul. 819 people (819 people x 2 vessels from 1638) were subject to the investigation. The investigation focused mainly on the entire carotid artery disease in patients. The investigation was carried out with the assistance of images of the Internal Carotid Artery (ICA), Duplex Ultrasound, and MRA of the Picture Archiving Communication System (PACS). Using the Gold standard as a guideline, MRA images can b classified as mild, moderate or severe depending on the degree of stenosis present in the 1CA. MRA images display higher results over ``oderate`` standard when it`` compared with ultrasound images. Unlike the Ultrasound images the Doppler image and the MRA image share some similarites. Some errors may be present when using ultrasound or MRA but by adding the doppler ultrasound study, evaluating the degrees of stenosis in the carotid artery will increase diagnostic accuracy.

의료용 선형 가속기 종류에 따른 방사선 치료기법에 대한 분석

김염재 ( Young Jae Kim ),동경래 ( Kyung Rae Dong ),여화연 ( Hwa Yeon Yeo ) 조선대학교 공학기술연구원 2012 공학기술논문지 Vol.5 No.3

The use of radiation therapy continues today as a treatment for cancer in radiation therapy devices. This study will be focused on the characteristics of medical radiation devices for the radiation oncology field. Clinac IX was developed or validated by Varian; it was com­bined with Intensity modulated Radiation Therapy (lMRT), Image-Guided Radiation Therapy (lGRT), and on board imaging that allow us to provide our patients with advanced radiation ther­apy. Varian Clinac IX linear accelerators capable of imaging cancerous tumor treatment areas during the actual process of radiation treatment, a process known a linage-Guided Radiation Therapy, or IMRT. Artiste CT Vision developed by Simens IMRT and IGRT. CT is able to pre­cise location of the internal organs in the cancer patients. Novalis TXTM is radiation treatment machine; the Novalis TxTM can treat many different types of cancer. Treatment table (Cauch)`s movement was wider than other devices. However, it has the disadvantage that it is more expensive than other device. Tomotherapy treatment equipment is likely to IMRT, IGRT treatment technique. However, before treatment it causes unnecessary patient exposure to radiation. As a result all the equipment studied here most1y available treatment techniques. Thus, when the introduction of new radiation therapy equipment in the hospital, which is imple­mented based on the treatment technique cost and patient care.