Volume Scan과 Helical Scan의 영상 및 선량 비교 평가

이현우(Hyun Woo Lee),이대로(Dae Roo Lee),강홍구(Hong Koo Kang),이성현(Sung Hyun Lee),김창남(Chang Nam Kim),김기원(Ki Won Kim) 대한CT영상기술학회 2013 대한CT영상기술학회지 Vol.15 No.1

목적 본 연구는 ACS 팬텀을 이용하여 Volume mode Scan과 Helical mode Scan을 실시하여 영상의 질 및 선량을 비교ㆍ평가하여 Volume Scan의 유용성을 알아보고자 한다. 대상 및 방법 640MSCT(Aquilion ONE, Toshiba, Japan)를 이용하여 ACS 팬텀을 Volume mode와 Helical mode그룹으로 나누어 8회 검사를 실시하였다. 횡단 영상을 획득하여 좌측 소뇌, 좌측 안구, 좌측 뇌실, 좌측 중대뇌동맥, 좌측 내경동맥의 ROI를 설정하였다. 각각의 위치에서 CT number (HU)와 Noise(SD), SNR을 측정하였고, DLP 값과 유효선량(ED)을 비교하였다. 유효선량은 DLP값과 두부 촬영 변환계수(k=0.0021 mSv/mGy×cm)로 계산하였다. 정량적 분석과 정성적 분석을 위해 각각 독립 t-test(Independent t-test)를 사용하여 통계적 유의성을 검정하였다. 결과 독립 t-test(Independent t-test)로 검증한 값들에서 P-value가 Eyeballs Helical Noise값에서만 0.031로 기각되었고, 나머지 다른 P값들은 0.05보다 크다는 결과를 얻었다. 또한 등분산을 가정한 각각의 t값에 따른 양측 검정에서 ICA SNR만 0.013과 0.014로 유의수준보다 작은 결과를 얻었고, 다른 양측검정에서는 유의수준보다 크게 나타났다. 검사로 인한 총 유효선량은 환산 결과 Helical mode에서 1.7±0.85(mSv), Volume mode에서 1.1±0.57(mSv)로 Volume mode의 방사선 피폭량이 Helical mode보다 약 1.56배 낮게 나타났고 통계적으로 유의한 차이를 보였다. 정성적 분석의 경우는 Helical mode 평균이 2.08±0.79, Volume mode의 평균은 1.91±0.79로 Helical mode의 평균점수가 높게 나타났다. 결론 Whole Brain CT 검사에 있어 Volume mode 검사는 Helical mode검사 보다 낮은 선량으로 높은 영상의 질을 제공할 뿐 아니라, Helical mode에 비해 빠른 스캔시간과 넓은 범위로 움직임이 심하거나 협조가 안되는 환자, 특히 수면검사가 필요한 소아의 검사에 있어 매우 유용한 검사라고 사료된다. Ⅰ. Purpose The purpose of this study was to compare image quality and radiation dose about volume scan and helical scan using ACS phantom and to evaluate the usefulness of volume scan. Ⅱ. Meterial and Methods Scan was carried out eight times, divided into groups of volume mode and helical mode using 640-MSCT (Aquilion ONE, Toshiba, Japan) using ACS phantom. After acquisitioning the transverse image, the ROIs of left cerebellum, left eye, the left ventricle, the left middle cerebral artery and the left internal carotid artery were established. CT number, noise and SNR were measured at each position and the DLP values and the effective dose (ED) were compared. DLP values and the effective dose were calculated as the head conversion factor (k = 0.0021 mSv / mGy × cm). Statistical significance was verified for quantitative and qualitative analysis using the independent t-test. Ⅲ. Result P-value 0.031 was reduced at independent t-test to verify the values in the Eye balls Helical Noise value and as only the rest of P values were greater than 0.05. Also, at each t value according to both side validation assuming the equal variances, SNR of ICA was 0.014 and 0.013 less than the level of significance, other both side validation was greater than the level of significance. The total effective dose equivalent from inspection was 1.7±0.85 (mSv) in helical mode and 1.1± 0.57 (mSv) in volume mode. Radiation exposure of volume mode was approximately 1.56 times lower than the Helical mode and showed a statistically significant difference. In the case of qualitative analysis, the averages of helical mode and volume mode were 2.08±0.79 and 1.91±0.79 respectively, the average score of helical mode was significantly higher. Ⅳ. Conclusions Volume mode of 640-MSCT is regarded as a useful inspection in the diagnosis of the brain diseases by providing low dose and high image quality than helical mode.

Dual source CT에서 high pitch chestpain cardiac scan mode를 이용한 angiography 검사의 유용성 평가

이대규(Dae Kyu Lee),이민영(Min Yung Lee),장광현(Kwang Hyun Chang) 대한CT영상기술학회 2015 대한CT영상기술학회지 Vol.17 No.1

목적 : 128 channel dual source computed tomography(이하 DSCT)의 high pitch mode를 이용하여 뇌혈관, 경동맥, 심장혈관을 1초 이하의 scan time 으로 한번에 검사하는 CT protocol 을 연구, 검사하였고 기존의 helical scan mode로 심장혈관을 검사하고, 조영제 추가 주입 후 뇌혈관, 경동맥을 같은 방법으로 검사한 영상을 비교하여 그에 따른 선량감소와 그 유용성을 비교해 보고자 하였다. 대상 및 방법 : 팬텀실험에서는 2개의 128-channel detector의 사용이 가능한 Somatom Definition Flash(Siemens Healthcare, Forchheim, Germany)CT 장비, organ dose 측정을 위해서 Alderson Rando phantom(CNMC Company, USA)을 사용하였다. 선량측정을 위해 형광유리선량계인 Dose Ace(GD-351, 12 mm, FGD-1000 reader, Asahi Techno Glass Cooperation, Shizuoka, Japan)를 사용하였다. 또한 유리 선량계를 주 선속 부위에 속하는 두부, 목, 폐, 심장 부위에 각각 2개씩 위치 organ dose를 측정하였다. 임상조건에서는 2014년 3월 부터 2014년 8월 까지 CCTA를 시행한 환자 210 명을 대상으로 이 중 heart rate가 60 이하인 104 명을 high pitch scan mode 로 검사하였고 106명은 helical scan mode로 검사하였다. Phantom 연구와 동일한 장비를 사용하고 같은 조건으로 나누어 검사 하였으며, 조영 증강을 위해서 이중 조영제주입기(dual flow injector, Stellant, Medrad, Inc, USA)를 사용하였다. 각각의 방법에서 두부, 목, 심장 부위의 CNR,SNR 을 측정하여 비교하였고, 영상은 4단계로 구분하여 2명의 영상의학과 심장판독 전문의가 평가하였다. 선량 평가는 CTDIvol, DLP와 유효선량을 평가하였고, 임상영상평가와 선량평가를 위한 통계학적 분석은 Levene의 등분산 검정을 통하여 정규성 검정을 하였고 통계학적 유의수준은 0.05 미만으로 하였다. 결과 : 1. Phantom 선량평가 : High pitch scan mode가 standard pitch scan mode & helical scan mode 에 비하여 effective dose 는 약 35.7% 정도 감소하였다(p<0.05). 2. 임상 연구 선량평가 : Head ~ coronary 까지 1 scan 으로 high pitch mode 에서 검사한 유효선량 값이 standard pitch & helical scan 로 나뉘어 2 scan 한 선량보다 약 30% 낮았다(p<0.05). 3. 임상영상평가 : 두 검사모드의 정성적 정량적 평가 값에서 모두 유의한 차이를 나타냈다(p<0.05). 결론 : Heart rate가 60대 이하이면서 안정된 환자에게 있어 Chest pain cardiac scan mode 로 검사 시, image quality는 떨어지지 않으면서도 2.5 mSv 이하의 저 선량으로 뇌혈관, 경동맥, 심장혈관을 한번에 검사할 수 있으므로 이는 곧 건강검진 환자나 심장 뇌혈관 질환 환자의 진단에 유용할 것으로 사료된다. Purpose : Using chest pain flash mode of 128 channel dual source computed tomography (below DSCT), we studied and tested one scanning CT protocol with less than 1 second scan time for intra cranial, carotid, and coronary vessel, then examined coronary angiography with helical scan mode, comparing the images that intra and carotid after injecting additional contrast media, following that purposed the dose reduction and usefulness. Materials & Methods: In this phantom test, Somatom Definition Flash (Siemens Healthcare, Forchheim, Germany)CT equipment for two 128-channel detector and Alderson Rando phantom(CNMC Company, USA) was used for the organ dose evaluation. For dose evaluation, Dose Ace (GD-351, 12 mm, FGD-1000 reader, Asahi Techno Glass Cooperation, Shizuoka, Japan) which is fluorescent glass dosimeter was used. Also, organ dose were measured by glass dosimeters positioning each two on head, neck, lungs and heart, belonging to the main flux. The clinical condition tested by high pitch scan mode with 104 patients whose heart rate was under 60 and tested by helical scan mode with 106 patients targeting 210 patients having CCTA from March 2014 to August 2014. Phantom studies using the same equipment and inspection were divided in the same condition, and the double-contrast injector (dual flow injector, Stellant, Medrad, Inc, USA) for enhancement was used. In the way each evaluated, was compared by measuring the head, neck and heart CNR, SNR, and evaluated two reading heart specialist of Radiology, separated by step of 4 images. Statistical analysis for the subjective assessment was used to Mann-Whiteny test of Graphpad Instat ver 3.05 and statistically significant was less than 0.05. CTDIvol, DLP and effective dose were evaluated to dose evaluation, for statistical analysis, normality test was used through equal variance examination, T- test were for analysis, and statistical significance level was done less than 0.05. Results: 1. Phantom dose evaluation: the effective dose of High pitch scan mode decreased about 35.7% (p <0.05) comparing to standard pitch scan mode & helical scan mode. 2. Clinical study dose evaluation: the effective dose value tested high pitch mode with one scan from head to coronary decreased about 30% (p <0.05) which done two scan by standard pitch and helical scan. 3. Clinical image evaluation: Both were significant differences in the two test mode for qualitative and quantitative evaluation value (p <0.05). Conclusion : If Scanning chest pain Flash scan mode for patients whose heart rate is below 60, it is possible that direct one scanning intra cranial, carotid, and coronary angiography exams with less than 2.5 mSv and image quality is equal. So it could be considered to diagnosis for health care and heart- brain vessel disease patients usefully.

Temporal bone CT 검사 시 conventional scan 방식과 helical scan방식에 따른 선량 비교분석

강수홍,박용성,이래곤,황선광,Gang, Su-hong,Park, Yong-Seong,Lee, Rae-Gon,Hwang, Seon-Kwang 대한디지털의료영상학회 2015 대한디지털의료영상학회논문지 Vol.17 No.1

Temporal bone CT scan side skull fracture. In addition to the confirmation of the ossicles, such as fractures and dislocations, temporomandibular facial fractures, deformities surgery helps to establish a science plan. Cochlear implant surgery has been performed in the state before and after identifying purposes. Test methods are being implemented by the Conventional direct axial and Direct coronal scan, the basic method of Temporal bone CT. Helical scan is a fast Volumetric data obtained compared with the Conventional scan, the patient reduced the dose, and there are some advantages, such as reduced Beam hardening streak artifacts caused by dental fillings. This study is a comparative analysis by dose reduction for patients with a dose according to the conventional scan method and then effective from 2015 by helical scan method performed in 2014 through the retrospective survey, which was then optimized for the purpose of inspection.

64채널 Multi-Detector Computed Tomography를 이용한 관상동맥검사의 선량

김문찬(Moon-Chan Kim) 대한방사선과학회(구 대한방사선기술학회) 2009 방사선기술과학 Vol.32 No.3

MDCT의 시간분해능 향상과 등방성 해상능(isotrophic resolution) 영상의 획득, 그리거 지능적인 심전도 동조를 바탕으로 하여 심혈관 질화의 효과적인 진단검사로 인정받고 있는 후향적 심전도 동조화(retrospective ECG gating) 하의 coronary CT angiography는 상대적으로 많은 환자선량을 제공함으로 인해 우수한 진단방법으로서의 장점을 반감시키고 있다. 이에 각 장치 제조사에서는 환자선량을 감소시키는 방법의 연구가 활성화되어 왔으며, 이의 일환으로 지능적인 cardiac dose modulation 기술과 전향적 심전도 동조화(prospective ECG gating)를 사용한 sequential scan이 도입되고 있다 이에 본 연구에서는 64 채널 MDCT에서 54kg, 163cm인 여성 인체모형팬덤을 대상으로 하고 형광유리선량계를 사용하여 후향적 심전도 동조화 하의 coronary CT angiography 프로토콜에서 환자선량의 정량적 평가화 환자선량 감소를 위해 본원에서 선택적으로 적용하고 있는 5가지 검사 프로토콜을 적용하였을 경우의 effective dose와 중요 부위의 organ dose 측정 비교하여 다음과 같은 결과를 얻었다. 1) Dose modulation없이 120kVp와 210mAs의 노출조건으로 retrospectively ECG gated helical scan으로 시행한 conventional coronary CT angiography 프로토콜의 effective dose는 17.8mSv였으며, 심장의 organ dose는 103.8mGy였다. 2) 관전압을 120kVp에서 100kVp로 낮추었을 경우 effective dose는 11.0mSv로 conventional coronary CT에 비해 38.2%가 감소하였으며, 심장은 67.3mGy로 45.2%가 감소하였다. 3) Cardiac dose modulation을 적용한 경우 effective dose 13.3mSv로 conventional coronary CT에 비해 25.3%가 감소하였으며, 심장은 80.0mGy로 22.9%가 감소하였다. 4) 100kVp의 저관전압과 cardiac dose modulation을 적용한 경우 effective dose 8.1mSv로 conventional coronary CT angiography에 비해 54.5%가 감소하였으며, 심장은 49.5mGy로 52.3%가 감소하였다. 5) Prospective ECG gating을 사용한 sequential scan을 시행하였을 때 effective dose는 4.9mSv로 conventional coronary CT에 비해 72.5%가 감소하였으며, 심장은 33.8mGy로 67.4%가 감소하였다. 6) 100kVp의 저관전압과 sequential scan을 적용하였을 때 effective dose는 3.0mSv로 conventional coronary CT angiography에 비해 83.2가 감소하였으며, 심장은 17.7mGy로 82.9%가 감소하였다. Purpose : To compare radiation dose for coronary CT angiography (CTA) obtained with 6 examination protocols such as a retrospectively ECG gated helical scan, a prospectively ECG gated sequential scan, low kVp technique, and cardiac dose modulation technique. Materials and Methods : Coronary CTA was performed by using 6 current clinical protocols to evaluate effective dose and organ dose in primary beam area with anthropomorphic female phantom and glass dosimetric system in 64 channel multi-detector CT. After acquiring topograms of frontal and lateral projection with 80kVp and 10mA, main coronary scan was done with 0.35 sec tube rotation time, 40mm collimation(0.625mm×64ea), small scan field of view (32cm diameter), 150mm scan length. Heart beat rate of phantom was maintained 60bpm in ECG gating, IN constant mAs technique 120kVp, 600mA was used, and 100kVp for low kVp technique. In a retrospectively ECG gated helical CT technique 0.22pitch was used. peak mA (600mA) was adopted in range of 40~80% of R-R interval abd 120mA(80% reduction) in others with cardiac dose modulation. And 210mAs was used without cardiac dose modulation. In a prospectively ECG gated sequential CT technique data were acquired at 75% R-R interval (middle diastolic phase in cardiac cycle), and 120msec additional padding of the tube-on time was used. For effective dose calculation region specific conversion factor of dose length product in thorax was used, which was recommended by EUR 16262. Results : The mean effective dose for conventional coronary CTA withour cardiac dose modulation in a retrospectively ECG gated helical scanwas 17.8mSv, and mean organ dose of heart was 103.8mGy. With low kVp and cardiac dose modulation the mean effective dose showed 54.5% reduction, and heart dose showed 52.3% reduction, compared with that of conventional coronary CTA. And at the sequential scan(SnapShot pulse mode) under prospective ECG gating the mean effective dose was 4.9mSv, this represents and 72.5% reduction compared with that of conventional coronary CTA. And heart dose was 33.8mGy, this represents 67.4% reduction. Inthe sequential scan technique under prospective ECG gating with low kVp the mean effective dose was 3.0mSv, this represents an 83.2% reduction compared with that of conventional coronary CTA. And heart dose was 17.1mGy, this represents an 82.9% reduction. Conclusion : In coronary CTA at retrospectively ECG gated helical scan, cardiac dose modulation technique using low kVp reduced dose to 50% above compared with the conventional helical scan. And the prospectively ECG gated sequential scan offers substantially reduced dose compared with the traditional retrospectively ECG gated helical scan.

Dual Source CT에서 High-pitch Cardiac Scan Mode를 이용한 관상동맥 검사의 유용성

이대규(Dae Kyu Lee),김문찬(Moon Chan Kim),방성호(Sung Ho Bang),한동균(Dong Kyoon Han) 대한CT영상기술학회 2010 대한CT영상기술학회지 Vol.12 No.1

Purpose To evaluate the usefulness of prospectively ECG gated high-pitch cardiac scan for CT coronary angiography(CTCA) using dual source CT by analyzing the dose effect and image quality for CTCA protocols. Materials and methods CTCA was performed by using 5 current clinical protocols to evaluate effective dose and organ dose in prima1y beam area with anthropomorphic female phantom and glass dosimetric system. Also, ACR phantom was used to analyze image quality at 128 channel multi-detector CT (scan parameters: 320 mAs at 120 kVp, collimation: 128 × 0.6 mm, scan range :137 mm, reconstructed slice thickness 0.6 mm, increment 0.4 mm). Heart beat rate of phantom was maintained 60 bpm in ECG gating. In a retrospectively ECG gated helical scan mode was done with 280 msecgantry rotation time, 0.23 pitch. Peak dose was used without cardiac dose modulation (pulsing off mode). Peak dose was adopted in range of 60%~80% of R-R interval and 25% reduction in others with cardiac dose modulation (pulsing manual mode). And peak dose was adopted in range of 60%~80% of R-R interval and 4% reduction in others with cardiac dose modulation (pulsing MinDose-manual mode). In a prospectively ECG gated sequential scan mode data were acquired at 70% R-R interval (middle diastolic phase in cardiac cycle), and 170 msec gantry rotation time was used. In a prospectively ECG gated high-pitch cardiac scan mode data were acquired from 60% R-R interval, and 3.4 pitch was used. Analysis of image quality was clone by evaluating objective noise, uniformity, high contrast resolution, and linearity. Results The mean effective dose for pulsing off mode without cardiac dose modulation in a retrospectively ECG gated helical scan was 20.8 mSv, and die mean organ dose of heart was 116.7 mGy. Pulsing manual mode showed 49% reduction, compared with that of pulsing off mode. And pulsing MinDose-manual mode showed 60% reduction compared with that of pulsing off mode. And at die adaptive sequential scan mode under prospective ECG gating die mean effective dose was 2.7 mSv, and die mean organ dose of heart was 17.5 mGy, d1is represents an 86% reduction compared with that of pulsing off mode. In the high pitch cardiac scan under prospective ECG gating die mean effective dose was 1.8 mSv, and the mean organ dose of heart was 10.3 mGy, this represents an 91% reduction compared with that of pulsing off mode. No differences in quantitative measures of linage quality were found between high pitch cardiac scan mode and others for noise, uniformity, high contrast resolution, linearity. Conclusion In patients with a low and stable heart rate, prospectively ECG gated high-pitch cardiac scan provides excellent image quality equivalent to retrospectively ECG gated helical scan-corelated acquisition but reduced effective dose.

A Study on the Reproducibility by Computed Tomography (CT) Using a Phantom

최재혁,조재환,이선엽,박철수 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.6

In general, computed tomography (CT) scanning methods for CT image acquisition include axialscanning methods, helical scanning methods and cine scanning methods. Many studies have reportedthe usefulness of four-dimensional computed tomography (4D CT) scanning for the planningof four-dimensional radiation therapy. On the contrary, no study has reported the reproducibilityof 4D CT images for the above-mentioned scanning methods. Therefore, in this study, a phantomthat could be moved independently was manufactured, and this manufactured phantom wasapplied in the same way as in the 4D CT method. Scanning was then performed using the threemethods so that the reproducibility of the image could be compared and analyzed. The study useda self-manufactured drive phantom and a respiration-gated drive motor to reproduce movementsin the upward/downward directions and in the top/bottom directions. Markers were placed onthe drive motor, and a radiopaque material (localizer) was attached to allow positional markingon the marker for the differentiation of movement when performing CT. The top/bottom movementwhen using the self-manufactured drive phantom was fixed at 1.3 cm (16 times/1 min), andthe upward/downward movement was fixed at 0.2 cm (8 rot/1 min) by using a respiration-gateddrive motor. After each movement had been fixed, images were taken with axial, helical and cinescanning for the three methods of CT. A radio-opaque material attached to the marker to indicatemovement was compared and analyzed by using radiation treatment planning (RTP) equipmentto ensure volume reproducibility. The study results revealed that the total volume of the markerwas 88.2 cm3, and when a 3-cm shift in the top/bottom directions and a 0.3-cm shift in the upward/downward directions were taken into account, the total volume was 184.3 cm3. By CT scantype, the total volume was 135 cm3 for axial scanning, 164.9 cm3 for helical scanning and 181.7 cm3for cine scanning. Regarding the reproducibility of movement, the cine scan depicted the markermuch better than the other scans did. In addition, the reproducibility of the radiopaque materialattached to the marker was better for the cine scan.

Arrhythmia 환자의 Coronary Computed Tomography Angiography에서 ECG-triggered FLEX Scan Mode 사용 시 선량과 영상의 질에 대한 연구

유흥준(Heung Joon Yoo),김민정(Min Jung Kim),박정훈(Jung Hoon Park) 대한CT영상기술학회 2013 대한CT영상기술학회지 Vol.15 No.1

서론 : 본 연구의 목적은 부정맥이 있는 환자를 대상으로 DSCT를 이용한 CCTA 검사에서 Retrospective ECG-gated helical scan mode와 Adaptive Cardio Sequence 기능을 갖고 있는 ECG-triggered FLEX scan mode를 통해 검사하였을 경우의 선량과 영상의 질을 비교 분석하여 임상에서의 유용성을 평가하고자 한다. 대상 및 방법 : 2012년 2월부터 2012년 12월까지 본원에서 CCTA 검사를 시행한 환자 중에서 심전도 동조 시 부정맥을 보이는 63명의 환자를 대상으로 하였으며, 33명은 ECG-triggered FLEX scan mode를 사용 하였고, 30명은 Retrospective ECG-gated helical scan mode를 사용하여 검사를 시행하였다. 각 mode별 유효 선량과 영상의 질을 비교 분석하였다. 결과 : 유효 선량의 평균값은 retrospective ECG-gated helical scan mode에서는 5.67mSv, ECG-triggered FLEX scan mode에서는 3.55mSv 였다. 평균적으로, ECG-triggered FLEX scan mode에서 선량이 37% 더 낮았다(P=0.002). ECG-triggered FLEX scan mode 그룹에서 영상의 질이 높이 평가 되었으며, 환자의 부정맥 패턴에 따라서는 심방세동에서 만큼은 ECG-triggered FLEX scan mode보다 retrospective ECG-gated helical scan mode에서 영상의 질이 더 높게 평가 되었으나, 통계학적 차이는 보이지 않았다. 결론 : 부정맥이 있는 환자의 CCTA 검사에서 advanced arrhythmia rejection 알고리즘을 이용한 ECG-triggered FLEX scan mode로 검사하였을 경우 retrospective ECG-gated helical scan mode로 검사 했을 때보다 피폭선량을 효과적으로 줄이면서도 영상의 질을 유지할 수 있다. Purpose : To determine clinical usefulness of ECG-triggered FLEX scan mode for patients with irregular heart rhythm in CCTA by comparing radiation dose and image quality with retrospective ECG-gated helical scan mode. Materials and methods : We selected 63 patients who showed arrhythmia in ECG monitoring in CCTA from February to December 2012. We divided these patients into two groups and performed CCTA using retrospective ECG-gated helical scan mode(n=33) and ECG-triggered FLEX scan mode(n=30). Then, we compared effective dose and image quality between two groups. Results : In retrospective ECG-gated helical scan mode, mean value of effective dose was 5.67 mSv and in ECG-triggered FLEX mode, 3.55 mSv, respectively. On average, radiation dose in ECG-triggered FLEX scan mode was 37% lower(P=0.02). Subjective score of image quality was higher in ECG-triggered FLEX scan mode groups except atrial fibrillation case. However, there was no statistical significance. Conclusion : In case of performing CCTA for patients having arrhythmia, radiation dose in ECGtriggered FLEX scan mode with advanced arrhythmia rejection algorhythm is 37% lower than that in retrospective ECG-gated helical scan mode without deteriorating image quality.

흉부CT 검사 시 HRCT 영상 재구성의 유용성

박성민,김긍식,강성민,유병규,이기배,Park, Sung-Min,Kim, Keung-Sik,Kang, Seong-Min,Yoo, Beong-Gyu,Lee, Ki-Bae 대한디지털의료영상학회 2015 대한디지털의료영상학회논문지 Vol.17 No.1

Purpose : Skip the repetitive HRCT axial scan in order to reduce the exposure of patients during chest HRCT scan, Helical Scan Data into a reconstructed image, and exposure of the patient change and visually evaluate the usefulness of the HRCT images. Materials and method : Patients were enrolled in the survey are 50 people who underwent chest CT scans of patients who presented to the hospital from January 2015 to March 2015. 50 people surveyed 22 people men and 28 people women people showed an average distribution of 30 to 80 years age was 48 years. 50 patients to Somatom Sensation 64 ch (Siemens) model with 120 kVp tube voltage to a reference mAs tube current to mAs (Care dose, Siemens) as a whole, including the lungs and the chest CT scan was performed. Scan upon each patient CARE dose 4D (Automatic exposure control, Siemens Medical Solution Erlangen, Germany) was to maintain the proper radiation dose scan every cross-section through a device that automatically adjusts the tube current of. CT scan is the rotation time of the Tube slice collimation, slice width 0.6 mm, pitch factor was made under the terms of 1.4. CT scan obtained after the raw data (raw data) to the upper surface of the axial images and coronal images for each slice thickness 1 mm, 5 mm intervals in the high spatial frequency calculation method (hight spatial resolution algorithm, B60 sharp) was the use of the lung window center -500 HU, windows were reconstructed into images in the interval -1000 HU to see. Result : 1. Measure the total value of DLP 50 patients who proceed to chest CT group A (Helical Scan after scan performed with HRCT) and group B (Helical Scan after the HR image reconstruction to the original data) compared with the group divided, analysis As a result of the age, but show little difference for each age group it had a decreased average dose of about 9%. 2. A Radiation read the results of the two Radiologist and a doctor upper lobe and middle lobe of the lung takes effect the visual evaluation is not a big difference between the two images both, depending on the age of the patient, especially if the blood vessels of the lower lobe (A: 3.4, B: 4.6) and bronchi(A: 3.8, B4.7) image shake caused by breathing in anxiety (blurring lead) to the original data (raw data) showed that the reconstructed image is been more useful in diagnostic terms. Conclusion : Scan was confirmed a continuous, rapid motion video to get Helical scan is much lower lobe lung reduction in visual blurring, Helical scan data to not repeat the examination by obtaining HRCT images reorganization reduced the exposure of the patient.

척수성근위축증 환자의 CT 유도하 치료제 투여 시 선량 감소 방안 연구

서영우,박성규,이민영 대한CT영상기술학회 2024 대한CT영상기술학회 학술대회자료집 Vol.2024 No.1