MDCT 장치의 선량이용률에 관한 연구

신상보(Sang Bo Shin),조원홍(Won Hong Cho),조남수(Nam Soo Cho) 대한CT영상기술학회 2005 대한CT영상기술학회지 Vol.7 No.1

This study was found out change factors of dose efficiency in multi- detector CT. The dose efficiency was analyzed by change of technical scan parameter such as kVp, mA, pitch, SFOV, beam collimation with 8 & 16 channels CT. The results obtained were as follows; 1. Dose efficiency was higher 20 mm beam collimation than 10 mm beam collimation in all devices. 2. Dose efficiency was higher at small focal spot than large focal spot in all devices. 3. There was no change of dose efficiency about change of pitch in all devices. 4. There was no change of dose efficiency about change of SFOV in all devices. 5. The 16 channels MDCT was higher dose efficiency than 8 channels MDCT.

소아 CT검사시 적정 노출조건 설정에 관한 연구

신상보(Sang Bo Shin),신설경(Sul Kyung Shin),이대규(Dae Kyoo Lee),김문찬(Moon Chan Kim) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose The increased radiation sensitivity of children causes them to have an age-dependent radiation risk that is 2-3 times larger than that of the general population. For this reason, the purpose of this study is selection of optimal x-ray exposure factors in pediatric CT. The absolute values for radiation exposure in CT depend strongly on the scan parameters, scanner characteristics, and the patients. Materials and Methods There are separate data provided for body applications(measured in a 32cm PMMA phantom) or head scans(16cm PMMA phantom). CTDI measurements are made at various positions within a body or head PMMA phantom. Measurements of the CTDI are performed in the center and 1cm below the surface of a cylindrical plexiglas phantom of 32cm diameter for the bodyand 16cm for the head. In a larger patient more is absorbed in the periphery so that the local dose in the center is less than it would be for a slimmer patient. Dose to the periphery also decreases for larger patients. Results CTDIw decreases with larger phantom diameters, which implies that the real average dose is underestimated for children and slim patients. Radiation induced risk in children can be substantially higher than the risk in the adult population. For this reason, the radiologist should double-check the indication for CT, and should adapt the radiation dose to the body cross-section. Longitudinal and adaptive dose modulation would be ideal technique, but presently only rough suggestion based on the body weight are available. One have to keep in mind, however, that the body weight may underestimate the dose requirements in obese children because their body cress-section can be larger than that of a taller child of identical weight. Tube current modulation takes advantage of the fact that there is a substantial difference in radiation attenuation of a body. Conclusion The best choice is adapts dose modulation at pediatric CT. This will be important step towards more constant image quality and dose reduction in CT.

폐 소결절 환자를 대상으로 한 CT-guided Wire Marking Procedure에 대한 유용성 평가

임상수(Sang Soo Lim),신상보(Sang Bo Shin),김문찬(Moon Chan Kim) 대한CT영상기술학회 2010 대한CT영상기술학회지 Vol.12 No.1

Purpose To prospectively assess the safety and effectiveness of computed tomography(CT)-guided marking using a wire before video-assisted thoracoscopic surgery for small pulmonary nodules, with characteristics and excision methods of pulmonary nodule suspicious to primary lung cancer. Materials and methods For June 2008 to July 2009, 35 patients(13 men, 22 women; range 34-75, mean age, 56 years) with Surgical removal for small pulmonary nodules were included in prospective study. With 4 channel CT scanner, the guided material was used 10 mm long, 21 gauge spring-hook type wire. Results The average CTDIVOL, effective close for each procedure were 7.80⊕3.16 mGy, 3.71⊕1.4 mSv respectively. Needle tip were completely targeted in nodule at 12(34.3%) out of 33 persons, at 13 persons(37%) into the direction of pleura and at 10 persons(28.6%) into the parenchyma rather than nodule. The mean diameter of the nodules, measured by CT scans, was 10.2⊕4.9 mm and ranged 0.3 mm to 2.8 mm. The distance of the nodules to visceral of pleura was 16.3⊕7.7 mm and ranged 4mm to 35 mm. From lesion characteristics of ground-glass opacity, pathological findings of adenocarcinoma was 29(82.8%). Metastatic cancer and immflamation were 3 persons (8.6%) respectively. In the procedure there was no complication in 19 persons(57.1%). tiny pneumothorax and hemorrhage were 13 persons(37.1%) and 2 persons(5.8%) respectively. And additional intervention was not required. Conclusion CT-guided marking wire procedure was very efficient with low radiation close, and minimizing to patients unrest in terms of low complications and simple procedure. Also it was useful study which could help minimizing resection of lung parenchyma including the nodule.

Intracranial CT Angiography에서 3D 영상의 재현성 평가

윤동민(Dong Min Yoon),신상보(Sang Bo Shin),신철경(Sul Kyung Shin),남윤철(Yoon Chul Nam),김문찬(Moon Chan Kim) 대한CT영상기술학회 2012 대한CT영상기술학회지 Vol.14 No.1

목적 두개 내 동맥의 CT검사 후 3D processing을 하는 경우 사용되는 각 장비들을 비교하여 특징을 알아보고 3D processing시 유용한 방법에 대하여 고찰해 보고자 한다. 대상 및 방법 3D processing을 하기 위한 영상을 얻기 위해 Toshiba사의 64 channel MDCT(Aquilion TSX-101A, Toshiba, Japan)를 사용하여 Intracranial artery를 검사한 30명의 영상을 이용하였으며, 동일한 검사 부위의 조영제 주입 전 영상인 non-contrast image(이하 pre image)와 조영제 주입 후 영상인 post contrast image(이하 post image)를 이용하였다. Pre image와 post image를 3D Processing 장비 ADW(GE, version 4.4), Tera-Recon(Aquarius, version 3.7.0.13), Rapidia(Infinitt, version 2.8), Aquilion workstation(Toshiba, version TSX-101A), Intuition(Aquarius, version 4,4)에 각각 전송하고 자체 기능을 이용하여 bone을 제거하여 혈관부위만 남긴 영상을 만들어 ICA(internal carotid artery), BA(basilar artery), ACA(anterior cerebral artery), MCA(middle cerebral artery), PCA(posterior cerebral artery) 부위를 비교하였다. 결과 Rapidia와 Aquilion workstation에서는 CT number값을 이용하여 pre image와 post image를 적용하는 subtraction을 이용하고 있다. Rapidia와 Aquilion workstation에서 bone의 제거가 용이했고 혈관소실이 거의 없었다. Intuition은 display된 pre image와 post image의 pixel을 이용하여 A-B의 형식으로 계산하여 나타내고 이후 auto bone remove기능을 이용하여 혈관과 bone을 구분한다. Intuition은 bone의 제거가 특정부위에서 어려웠고 혈관소실도 있었다. ADW도 display된 pre image와 post image의 pixel을 이용하여 A-B의 형식으로 계산하여 나타내고 이후 auto bone remove기능을 이용하여 혈관과 bone을 구분한다. ADW는 bone의 제거는 용이했지만 특정부위의 혈관소실이 있었다. Tera-recon은 auto bone remove 기능을 이용하여 혈관에서 bone을 제거한다. Tera-recon에서는 bone의 제거가 특정부위에서 어려웠고 혈관소실도 있었다. 결론 CT검사 후 데이터를 이용하여 3D processing을 함에 있어 CT number값을 이용하여 pre image와 post image를 적용하는 subtraction의 기능을 이용하는 Rapidia와 Aquilion workstation의 사용이 보다 유용한 영상을 표현해내며 이는 원본 데이터의 왜곡을 최소화 하고 보다 실제에 가까운 3D 영상을 만든다. I. Purpose When using the 3D processing after the CT scan of intracranial arteries, study of best way to 3D processing and knowing the characteristics of each workstation. II. Material and methods For gain to the 3D image, 30 patients images that underwent CT Angiography, Intracranial Arteries by Toshiba 64 channel MDCT(Aquilion TSX-101A, Toshiba, Japan), images transferred to each 3D processing equipments. Pre and pat image was using the same location, and this images transfer to ADW(GE, version 4.4), Tera-Recon(Aquarius, version 3.7.0.13), Rapidia(Infinitt, version 2.8), Aquilion workstation(Toshiba, version TSX-101A), Intuition(Aquarius, version 4.4). Each workstation makes a 3D artery image without foreign object such as bone, vein, peripheral vessel, it using the self function at that time. Then, conμire the ICA(internal carotid artery), BA(basilar artery), ACA(anterior cerebral artery), MCA(middle cerebral artery), PCA (posterior cerebral artery). III. Result Rapidia and Aquilion workstation was using the CT number, then it takes a subtraction by pre and past image. Rapidia and Aquilion workstation was so useful equipments fee remove the bone and there was little or no loss of vessel. Intuition is using the display pixel of pre and past image, then appear to image such as A-B and compare vessel with bone by auto bone remove function. Intuition is hard to remove the bone and loss of vessel. ADW is also using the display pixel of pre and past image, then appear to image such as A-B and compare vessel with bone by auto bone remove function. ADW is useful equipments for remove the bone but it has loss of vessel. Tera-Recon takes a auto bone remove function and remove the bone from the vessel. Tera-Recon is hard hard to remove the bone and loss of vessel. IV. conclusion When using the 3D processing workstation for 3D image, Rapidia and Aquilion workstation subtraction function that apply to CT number of pre and post image is minimize distortion and so useful to mike a realistic 3D image.

CT검사시 목적장기 이외 부위의 차폐를 통한 피폭선량감소 효과에 관한 연구

이홍(Hong Lee),김문찬(Moon Chan Kim),신상보(Sang Bo Shin) 대한CT영상기술학회 2009 대한CT영상기술학회지 Vol.11 No.1

Purpose The study was done to evaluate radiation dose reduction effect through shielding like scattering ray to superficial radiosensitive organs which are adjacent to scanning field when head & neck, chest & abdomen CT examination. Materials and methods LightSpeed VCT(General Electric medical system, Milwaukee, USA) was used as CT equipment and Rando phantom(model RAN-110, Churchin associate LTD., USA) and glass dosimetry system(GD-351, 8.5mm, FGD-1000) in the measurement of radiation dose. There were two kinds of materials to shield from radiation, a lead apron(0.5mm Pb at 80kVp) was used in out-plane and bismuth(F & L medical products co.) was used in in-plane. The measurement of organs was divided into brain, neck, chest and abdomen. Scan protocol was as follow: 1. In the brain examination, 120kVp and dose modulation(1sec, min. 150~max. 250mA, noise index: 2.80) was used for the examination. The glass dosimetry elements were put on left and right lens of phantom eyeball(thyroid), and the radiation dose without and with the use bismuth(Pb) shield were measured three times. 2. In the neck examination, 120kVp and dose modulation(0.6sec, min. 150~max. 300mA, noise index: 6.0) was used for the examination. The glass dosimetry elements were put on left and right lens of phantom eyeball(the both nipples), and the radiation dose without and with the use bismuth(Pb) shield were measured three times. 3. In the chest examination, 120kVp, dose modulation(0.6sec, min. 100~max. 230mA, noise index: 15.86) was used of the pre-contrast and 120kVp, dose modulation(0.6sec, min. 100~max. 275mA, noise index: 15.86) was used of the post-contrast. The glass dosimetry elements were put on left and right phantom thyroid(umbilicus), and the radiation dose without and with the use bismuth(Pb) shield were measured three times. 4. In the abdomen examination, 120kVp and dose modulation(0.6sec, min. 100~max. 300mA, noise index: 11.57) used for examination. The glass dosimetry elements were put on the both nipples of phantom breast(gonad), and the radiation dose without and with bismuth shield were measured three times. Results 1. In brain CT scanning, shielding with bismuth of lens of eyeballs decreased the radiation dose about 46%(without: 43.98mGy, with: 23.86mGy) and shielding with Pb of thyroid decreased the radiation dose about 24%(without: 1.21mGy, with: 0.92mGy). 2. In neck CT scanning, shielding with bismuth of lens of eyeballs decreased the radiation dose about 42%(without: 66.47mGy, with: 38.58mGy) and shielding with Pb of breast decreased the radiation dose about 65%(without: 2.43mGy, with: 0.86mGy). 3. In chest CT scanning, shielding with bismuth of thyroid decreased the radiation dose about 22%(without: 20.74mGy, with: 16.1mGy) and shielding with Pb of umbilicus decreased the radiation dose about 44%(without: 1.34mGy, with: 0.75mGy). 4. In abdomen CT scanning, shielding with bismuth of breast decreased the radiation dose about 13%(without: 1.80mGy, with: 1.58mGy) and shielding with bismuth of gonad decreased the radiation dose about 33%(without: 23.08mGy, with: 15.46mGy). Conclusion According to the study, a percentage of the measured dose reduction is from min. 22% to max. 65%. The results have important meaning that there is much possibility of additional dose reduction through shielding not only in-plane but also out-plane. Consequently, the radiation dose given to patients can be decreased through the CT workers’ effort and concern like shielding out-plane from radiation.

두개부와 흉부 CT 검사시 Bismuth 차폐재를 이용한 안구의 렌즈와 유방의 선량감소에 대한 평가

변정인(Jung in Byun),남윤철(Yoon chul Nam),이홍(Hong Lee),신상보(Sang bo Shin),한동균(Dong kyoon Han) 대한CT영상기술학회 2008 대한CT영상기술학회지 Vol.10 No.1

Purpose Bismuth shield can filter twice in that penetrates X-ray, which is essential in diagnosis, and it also partially decreases skin dose. Hence, it is necessary to study the effects in reduction of absorbed dose on highly sensitive organs, which are included in the regions of cranial and chest CT exams. Materials and methods All exams were proceeded on LlghtSpeed 16MDCT (GE Medical System, Milwaukee, U.S.A.), Rando phantom (Model RAN-110, Churchin associate LID., USA) and Glass dosimetry system(GD-351,8.5mm, FGD-1000) for the measurement of radiation dose. In addition, AttenuRad radiation protection devices of eyeballs & breast (F&L Medical Products Co.) are used for protection of sensitive organs. In cranial examination, the brain CT protocols was used for the examinations, and the summary of it is as followed: The glass radiation elements were put on left and right lens of phantom eyeballs, and the radiation before and after the use of Bismuth shield were measured twice when 120kVp of current were changed into 150mAs, 200mAs, and 200mAs, and when 250mAs were changed into 100kVp, 120kVp, and 140kVp. In chest examination, low-dose protocol and chest routine protocol are used for the examination. The conditions of low-dose protocol are as followed:120kVp, noise index 11.57(10~50mA), tube rotation time 0.8sec, pitch 1.375, and table speed 13.75mm/sec. Also, the conditions of chest routine CT protocol are 120kVp, noise index 15.86(160~250mA), tube rotation time 0.8sec, pitch 1.35, and table speed 13.5mm/sec. The glass elements were put on the both nipples of phantom and the radiation before and after the use of bismuth shield were measured twice. When the shield is used, rubber-made spacer(1cm) should be on the breasts, followed by bismuth shield, because it decreases not only the scattering ray absorption into breast wall caused by bismuth shield but image artifact potentially. Results The result of the measurement of orbit shielding during cranial examination. The results of measurements of the radiation(from 120kVp to 150, 200, 250 and 300mAs) before and after the use of bismuth shield are as followed: from 18.4±0.3mGy to 10.25±0.5rnGy(44.3% decrease) at 150mAs; from 23.9±0.9mGy to 13.9±0.1mGy(41.5% decrease) at 200mAs; from 37.3±0.3mGy to 19.8±0.9mGy(47.1% decrease) at 250mAs; and from 47.8±3.4mGy to 24.4±1.4mGy(46.8% decrease) at 300mAs. On the other hand, the measurements of radiation(from 250mAs to 100, 120, and 140 kVp) before and after the use of bismuth shield are as followed: from 22.9±0.2mGy to 22.9±0.2mGy(51.2% decrease) at 100kVp; from 34.4±0.9mGy to 19.5±0.2mGy(43.3% decrease) at 120kVp; and from 49.5 ±4.4mGy to 29±1.2mGy(41.4% decrease) at 140kVp. The result of the measurement of orbit shielding during breast examination. In low-dose protocol, the results of measurements of the radiation before and after the use of bismuth shield are 3.16±0.02mGy and 2.44±0.03mGy(22.78% decrease), respectively, and in chest routine protocol, the results were 14.45±1.08mGy and 11.93±0.21mGy(17.43% decrease), respectively. Conclusion In cranial examination, there was not much change in the radiation dose of eye lens with an application of bismuth shield, even increases of mAs with constant kVp. On the other hand, the rate of reduction of radiation dose by bismuth shield is seen with constant mAs and increase of kVp. Due to the use of bismuth shield, radiation dose has been decreased about 22.8%in low-dose study, and 17.4% in chest routine study. In our hospital, the use of bismuth shield of orbit is not applied to adults, but applied to some infants only when brain CT exam was operated to them. The breast shield is applied, as a test, to women under 50 years old. According to this study, the results show obviously that the use of the bismuth shield can reduce radiation dose of highly radiation-sensitive organs. As mentioned before, the amount of radiation that eye balls received at 250mAs(at