• 대한의용생체공학회:의공학회지
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• 제25권4호
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• pp.269-275
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• 2004

인체내부의 각 조직은 서로 다른 저항률(resistivity)분포를 가지며, 조직의 생리학적, 기능적 변화에 따라 임피던스가 변화한다. 본 논문에서는 주로 기능적 영상을 위한 임피던스 단층촬영 (EIT, electrical impedance tomography) 시스템의 설계와 구현 결과를 기술한다. EIT 시스템은 인체의 표면에 부착한 전극을 통해 전류를 주입하고 이로 인해 유기되는 전압을 측정하여, 내부 임피던스의 단층영상을 복원하는 기술이다. EIT 시스템의 개발에 있어서는 영상복원의 난해함과 아울러 측정시스템의 낮은 정확도가 기술적인 문제가 되고 있다. 본 논문은 기존 EIT 시스템의 문제점을 파악하고 디지털 기술을 이용하여 보다 정확도가 높고 안정된 시스템을 설계 및 제작하였다. 크기와 주파수 및 파형의 변화 가능한 50KHz의 정현파 전류를 인체에 주입하기 위해 필요한 정밀 정전류원을 설계하여 제작한 결과, 출력 파형의 고조파 왜곡(THD, total harmonic distortion)이 0.0029%이고 진폭 안정도가 0.022%인 전류를 출력 할 수 있었다. 또한, 여러개의 정전류원을 사용함으로써 채 널간 오차를 유발하던 기존의 시스템을 변경하여, 하나의 전류원에서 만들어진 전류를 각 채널로 스위칭하여 공급함으로써 이로 인한 오차를 줄였다. 주입전류에 의해 유기된 전압의 정밀한 측정을 위해 높은 정밀도를 갖는 전압측정기가 필요하므로 차동증폭기, 고속 ADC및 FPGA(field programmable gate array)를 사용한 디지털 위상감응복조기 (phase-sensitive demodulator )를 제작하였다. 이때 병렬 처리를 가능하게 하여 모든 전극 채널에서 동시에 측정을 수행 할 수 있도록 하였으며, 제작된 전압측정기의 SNR(signal-to-noise ratio)은 90dB 이다. 이러한 EIT 시스템을 사용하여 배경의 전해질 용액에 비해 두 배의 저항률을 가지는 물체(바나나)에 대한 기초적인 영상복원 실험을 수행하였다. 본 시스템은 16채널로 제작되었으나 전체를 모듈형으로 설계하여 쉽게 채널의 수를 늘릴 수 있는 장점을 가지고 있어서 향후 64채널 이상의 디지털 EIT시스템을 제작할 계획이며, 인체 내부의 임피던스 분포를 3차원적 으로 영상화하는 연구를 수행 할 예정이다.

• 대한핵의학회지
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• 제30권1호
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• pp.35-46
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• 1996

Dopamine transporter concentrations have been known to decrease in Parkinson's disease (PD) or increase in Tourette's disorder. The purpose of this study was to evaluate the effectiveness of [I-123]N-(3-iodopropene-2-yl)-$2{\beta}$-carbomethoxy-$3{\beta}$-(4-chlorophenyl) tropane (IPT) as an imaging agent for measuring changes in transporter concentrations with PD. IPT labelled with 6.69+/-0.64 mCi(247.53+/-23.68 MBq) of I-123 was intravenously injected into ten patients(age: 55+/-11) with PD, and six normal controls(NC)(age: 46+/-14) as a bolus. Dynamic SPECT scans of the brain were then performed for 5 minutes each over 120 minutes on a triple headed camera. Time activity curves were generated for the left basal ganglia(LBG), right basal ganglia(RBC), and occipital cortex(OCC). The statistical parameters included the time to peak activity, the contrast ratio of LBG and RBG to OCC at several time points, and the accumulated specific binding counts/mCi/pixel(ASBC) from 0 to 115 minutes. The uptake of IPT in the brains of PD and NC peaked within 10 minutes of injection in all subjects. The maximum target to background ratio in the basal ganglia of PD and NC occurred at 85+/-20 min and 110+/-6 min of injection, respectively. The BG/OCC ratios at 115 minutes for PD and NC were 2.15+/-0.54 and 4.26+/-0.73, respectively. The ASBC at 115 minutes for PD and NC were 152.91+/-50.09 and 289.51+/-49.00, respectively. The ratio of BG/OCC for the NC was significantly higher than the ratio for PD. SPECT data matched with clinical diagnosis for PDs. The ratio between BG and OCC and the ASBC for PD were clearly separated from NC and may be useful outcome measures for clinical diagnosis. The findings suggest that IPT may be a very useful tracer for early diagnosis of PD and study of dopamine reuptake site.

• 대한디지털의료영상학회논문지
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• 제13권2호
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• pp.63-69
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• 2011

Table strapis patient fixture for securing the patient movements and falls. if it designed to measure the abdominal circumference and used as an indicator of dose selection at CT scan. it will prevent the overexposure of dose without degradation of image quality and efficiently manage dose of each type of body to technician to deal with CT. First, in order to compare the dose used in CT image and qualitative characteristics. reference image is obtained by examining the abdominal phantom in same conditions with the hospital 120 kVp, 200 mAs, D-Dom (Dynamic Dose Of Modulation). SNR, PSNR, RMSE, MAE, CTDIvol of CT images are compared with reference image. for comparing with reference image, the image that Umbilicus level image of Abdomen CT is stored in the PACS were used. For comparison, the top 12 o'clock portion of the air drawn from the same ROI was measured. CTDIvol, mAs, etc. In order to analyze the characteristics of the image, by measuring the length of the umbilicus circumference, pattern of the dose was analyzed. by using the analyzed perimeter and dose information, To be identified visually, fixed band that scale marked were produced. Use them, If the length of circumference of less than 60 cm 100 mAs, Case of 61~80 cm 120 mAs, Case of 80~100 cm 150 mAs, more than 100 cm 200 mAs, dose selection based on the perimeter, the image was applied. by compare analyzed with the Reference Image, image quality was assessed. by compare with existing tests that equally 200 mAs applied, How much was confirmed that the dose reduction. 1. Depending on the Abdominal circumference, the average PSNR(dB) of the image that differently dose applied was 45.794. 2. Comparing with existing test. the dose of scan that adjusted the mAs depending on the circumference was decreased about 40%. SNR and PSNR of the image that obtained by adjusting the standard mAs based on dose modulation were not much different. Therefore, By choosing a low mAs. dose reduction can be obtained. and the dose selection method that measured Abdominal circumference using a fixed band can protect the overexposure and uniformly apply dose of each type of body to technician to deal with CT.

• 방사선산업학회지
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• 제11권1호
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• pp.1-6
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• 2017

Reported some level of bacteria in areas that are well made contact in Radiology imaging room evaluate the importance of cleanliness in the hospital management of equipment to check for the presence of pathogenic bacteria. Gwang-ju and Jeol-la city and medium-sized hospitals in the material with a cotton swab and rub evenly Radiology selection cassette, a handle, Apron of the imaging apparatus having the most contact with patients from July 2016 to August 2016 as a target in place and special studios 6, and saline solution will placed in a test tube containing. The swab sample was diluted 1,000 times, you can see the bacteria and the intestinal bacterial selective medium Trypticase Soy Agar (TSA), Muller-Hinton Agar (MHA), Eosin-Methylene Blue (EMB), ENDO(BD, NJ, USA) then incubated smear to. In the incubator (incubator, SANYO, Japan) was observed after incubation of bacteria and counting the total number of bacteria also Colonies (colony) suspected intestinal bacteria were isolated and cultured on KIA medium (BD, NJ, USA). As a result, it was found that this came Gram positive Coccus A hospital handle the F hospital, from the C Gram positive Coccus cassette and handle the F hospital. The striking yellow coloring Staphylococcus aureus 110 agar (STA 110) in the medium sample, but it is suspected staphylococcal Coccus to the final identification in the laboratory is not a single specimen of the two samples from Gram positive Coccus biochemical identification Identification Kit is an API could not, it was thought to be non-Staphylococcus aureus was cultured on blood agar suggesting that (BAP) blood of dance. Dynamic tests were conducted biochemical API kit of the two samples were identified from Gram positive Coccus bacteria Escherichia coli (E. coli) is F hospital cassette was confirmed Eenterobacter cloaca in A hospital possession. Did not aggregate O-26, O-111, O-157 and the serum test was conducted in the laboratory from the E. coli F cassette hospital.

• 한국지반공학회논문집
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• 제23권4호
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• pp.33-46
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• 2007

HWAW 기법은 체적파 영향이 포함된 표면파를 이용하는 지표면 지반조사 기법이다. 짧은 감지기 간격을 이용하여 지반의 전단파 속도 주상도를 도출할 수 있으므로 지반 강성의 2차원 영상을 도출하는데 장점이 있다. 경사지반에 대한 HWAW 기법의 신뢰성을 수치해석을 통해 검증한 바 있으나 실제 현장에서는 지반의 정확한 전단파 속도 분포를 알 수 없으므로 기법의 실제 현장에서의 신뢰성은 검증하기가 매우 어렵다. 따라서 본 연구에서는 HWAW 기법의 현장 검증을 효율적으로 수행하고자 대상지반 지층의 구조적 형상 및 전단파 속도 분포를 알 수 있는 실대형 모형부지를 조성하였다. 모형부지의 구조적 형상은 모형부지 조성 과정 중에 측량을 통하여 확인하였으며 동적물성치는 성토 과정 중 모형부지 내에 매설된 다수의 속도계를 이용하여 획득하였다. 이렇게 획득한 모형부지의 층상구조 및 전단파 속도 분포를 바탕으로 부지의 2차원 기준 값을 결정하였으며 HWAW기법 검증 및 기타 탄성파 탐사들의 비교연구를 수행하였다. 이를 통해 HWAW기법이 다른 탄성파 탐사 기법에 비하여 현장 지반의 2차원 전단파 속도 분포를 신뢰성 있게 도출함을 확인하였다.

• Korean Journal of Radiology
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• 제23권10호
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• pp.976-985
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• 2022

Objective: To compare the clinical and radiological features of various etiologies of chronic diffuse lacrimal gland enlargement. Materials and Methods: We retrospectively reviewed 91 consecutive patients who underwent surgical biopsy for chronic diffuse lacrimal gland enlargement and were diagnosed with non-specific dacryoadenitis (DA) (n = 42), immunoglobulin G4-related dacryoadenitis (IgG4-RD) (n = 33), and lymphoma (n = 16). Data on patient demographics, clinical presentation, and CT imaging findings (n = 73) and MRI (n = 43) were collected. The following radiologic features of lacrimal gland enlargement were evaluated: size, unilaterality, wedge sign, angle with the orbital wall, heterogeneity, signal intensity, degree of enhancement, patterns of dynamic contrast-enhanced, and apparent diffusion coefficient value. Radiological features outside the lacrimal glands, such as extra-lacrimal orbital involvement and extra-orbital head and neck involvement, were also evaluated. The clinical and radiological findings were compared among the three diseases. Results: Compared to the DA and IgG4-RD groups, the lymphoma group was significantly older (mean 59.9 vs. 46.0 and 49.4 years, respectively; p = 0.001) and had a higher frequency of unilateral involvement (62.5% vs. 31.0% and 15.2%, respectively; p = 0.004). Compared to the IgG4-RD and lymphoma groups, the DA group had significantly smaller lacrimal glands (2.3 vs. 2.8 and 3.3 cm, respectively; p < 0.001) and a lower proportion of cases with a wedge sign (54.8% vs. 84.8% and 87.5%, respectively; p = 0.005). The IgG4-RD group showed more frequent involvement of the extra-orbital head and neck structures, including the infraorbital nerve (36.4%), paranasal sinus (72.7%), and salivary gland (58.6%) compared to the DA and lymphoma groups (4.8%-28.6%) (all p < 0.005). Conclusion: Patient age, unilaterality, lacrimal gland size, wedge sign, and extra-orbital head and neck involvement differed significantly different between lymphoma, DA, and IgG4-RD. Our results will be useful for the differential diagnosis and proper management of chronic lacrimal gland enlargement.

• Korean Journal of Radiology
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• 제24권7호
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• pp.647-659
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• 2023

Objective: The study was conducted to investigate the effect of correct occlusion of the left atrial appendage (LAA) on intracardiac blood flow and thrombus formation in patients with atrial fibrillation (AF) using four-dimensional (4D) flow magnetic resonance imaging (MRI) and three-dimensional (3D)-printed phantoms. Materials and Methods: Three life-sized 3D-printed left atrium (LA) phantoms, including a pre-occlusion (i.e., before the occlusion procedure) model and correctly and incorrectly occluded post-procedural models, were constructed based on cardiac computed tomography images from an 86-year-old male with long-standing persistent AF. A custom-made closed-loop flow circuit was set up, and pulsatile simulated pulmonary venous flow was delivered by a pump. 4D flow MRI was performed using a 3T scanner, and the images were analyzed using MATLAB-based software (R2020b; Mathworks). Flow metrics associated with blood stasis and thrombogenicity, such as the volume of stasis defined by the velocity threshold ($\left|\vec{V}\right|$ < 3 cm/s), surface-and-time-averaged wall shear stress (WSS), and endothelial cell activation potential (ECAP), were analyzed and compared among the three LA phantom models. Results: Different spatial distributions, orientations, and magnitudes of LA flow were directly visualized within the three LA phantoms using 4D flow MRI. The time-averaged volume and its ratio to the corresponding entire volume of LA flow stasis were consistently reduced in the correctly occluded model (70.82 mL and 39.0%, respectively), followed by the incorrectly occluded (73.17 mL and 39.0%, respectively) and pre-occlusion (79.11 mL and 39.7%, respectively) models. The surfaceand-time-averaged WSS and ECAP were also lowest in the correctly occluded model (0.048 Pa and 4.004 Pa^-1, respectively), followed by the incorrectly occluded (0.059 Pa and 4.792 Pa^-1, respectively) and pre-occlusion (0.072 Pa and 5.861 Pa^-1, respectively) models. Conclusion: These findings suggest that a correctly occluded LAA leads to the greatest reduction in LA flow stasis and thrombogenicity, presenting a tentative procedural goal to maximize clinical benefits in patients with AF.

• Journal of Yeungnam Medical Science
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• 제27권2호
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• pp.105-112
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• 2010

병리조직학적으로 고환림프종으로 확진된 예들의 초음파검사 및 자기공명영상을 후향적으로 분석하여 다른 고환종양과 구분할 수 있는 소견이 있는지를 알아보기 위하여 본 연구를 시행하였다. 수술적 절제에 의해 확진된 7예와 초음파-유도하 조직생검으로 확진된 1예 등 총 8예를 대상으로 하였다. 종괴의 크기와 위치, 고환 이외에 침범된 장기를 조사하였고, 초음파검사에서는 종괴의 모양과 경계, 종괴 내부의 에코, 균일도와 함께 색도플러검사에서의 혈관분포상태를 조사하였다. 자기공명영상이 시행된 4예를 대상으로 종괴의 모양과 경계, 균일도, T1-및 T2-강조영상에서의 신호강도 및 조영증강 여부와 시간에 따른 조영증강의 변화를 조사하였다. 고환에 국한되어 있었던 경우는 2예에 불과하였고, 4예는 정삭을, 4예는 대동맥주위림프절을 침범하고 있었다. 초음파검사에서 종양의 외연은 6예에서 평활하였고 종괴의 에코는 7예에서 정상 고환 보다 저에코로 보였다. 4예는 균일하였고, 3예는 전반적으로는 균일하였으나 약간 불균일한 부분을 포함하고 있었고, 1예는 불균일하였다. 8예 모두에서 주변의 정상 조직보다는 현저하게 혈관분포상태 (vascularity)가 증가되어 있었다. 자기공명영상 T1-강조영상에서는 정상 고환과 유사한 신호강도로, T2-강조영상에서는 현저한 저신호강도로 관찰되었고 대체로 균일하였다. 조영 후 검사에서는 4예 모두 정상 고환 조직보다는 저신호강도로, 약하게, 균일하게 조영증강되었는데, 역동적 조영증강 검사가 시행된 1예에서는 시간이 감에 따라 점차 조영증강이 증가되는 소견을 관찰할 수 있었다. 이상의 결과를 토대로 50세 이상의 나이가 많은 환자에서 고환 종괴가 관찰되고, 초음파 검사에서 균일한 저에코로, 자기공명영상 T2-강조영상에서 균일한 저신호강도로 관찰될 때에는 고환림프종의 가능성을 가장 먼저 고려하여야할 것으로 생각한다.

• 대한수의학회지
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• 제44권1호
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• pp.15-21
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• 2004

This paper describes the development of $^{99m}Tc$ tricarbonyl cysteine as potential renal function diagnostic radiopharmaceutical and evaluation of its biological characteristics using experimental animals. l-Cysteine was labeled efficiently with $^{99m}Tc$ tricarbonyl precursor $([^{99m}Tc(CO)_3(H_2O)_3)]^{+})$ under 30 min heating at ${75^{\circ}C}$. Labeling yield and stability were analyzed by high performance liquid chromatography (HPLC). The biodistribution property of $^{99m}Tc$ tricarbonyl cysteine in mice and its dynamic imaging profiles in rabbits were carried out. To investigate the excretion mechanism of $^{99m}Tc$ tricarbonyl cysteine, tubular transport inhibition test with probenecid was adopted. $^{99m}Tc$ tricarbonyl cysteine was obtained with a high labeling yield under the moderate condition. The results of biodistribution experiments of $^{99m}Tc$ tricarbonyl cysteine in ICR mice at 3 and 90 min provided that $^{99m}Tc$ tricarbonyl cysteine was very highly accumulated in the kidney and bladder, thereby almost 99% of $^{99m}Tc$ tricarbonyl cysteine was excreted within 90 min post injection. The same results were confirmed by the whole body dynamic images for 30 minutes and static images in rabbits at given time intervals after injection. Renogram of $^{99m}Tc$ tricarbonyl cysteine in rabbits showed that its $T_{max}$ and $T_{1/2}$ of $^{99m}Tc$ tricarbonyl cysteine were $2.33{\pm}0.56$ and $4.30{\pm}0.79$ min, respectively. The $T_{max}$ of $^{99m}Tc$ tricarbonyl cysteine with probenecid pretreatment was $2.30{\pm}0.17$ min, whereas $T_{1/2}$ of that with probenecid pretreatment was $17.0{\pm}32.47$ min. $T_{1/2}$ of $^{99m}Tc$ tricarbonyl cysteine with probenecid pretreatment was significantly different, as compared to the result without probenecid (p<0.0001). The results showed that the excretion of $^{99m}Tc$ tricarbonyl cysteine was extremely affected by probenecid. Therefore, $^{99m}Tc$ tricarbonyl cysteine was rapidly excreted from the kidney principally by the tubular secretion.

• 한국측량학회지
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• 제30권2호
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• pp.143-152
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• 2012

항공영상을 이용하여 수치표면자료와 같은 3차원 자료를 자동으로 제작하기 위해서는 영상정합이 반드시 필요하다. 최근 사용되고 있는 항공 디지털 프레임 영상은 과거의 아날로그 영상에 비해 폐색지역이 적은 고중복도 다중 스트립 영상으로 촬영되기에 용이하다. 최근 다중 스트립 영상을 이용한 다중영상정합 기법에 대한 연구가 많이 이루어지고 있으며, 특히 각 영상에서 추출된 점(point feature)이나 형상(linear feature)의 유사성 측정 방법에 대한 연구가 진행되고 있다. 본 연구에서는 수직궤적 기반 다중영상정합을 대상으로 영역기반 유사성 측정 방법으로 SNCC(Sum of Normalized Cross-Correlation)와 SSD(Sum of Squared-Difference) 방법을 비교 분석하였다. 또한 영역기반 유사성 측정에 필요한 요소로 영상의 화소값, 화소값 기울기 강도, 화소값과 화소값 기울기 강도 평균을 각각 사용하여 결과를 비교하였다. 이 외에도 영역기반 유사성 측정에서 중요한 요소인 기준 윈도우의 크기를 비정규 적응형 기준 윈도우 방법과 정규 적응형 윈도우 방법을 적용하여 결과를 비교 분석하였다. 실험을 위하여 사용된 항공영상은 ZI Imaging 사의 DMC (Digital Modular Camera)에 의해 종중복도는 80%, 횡중복도는 60%로 촬영되었으며, 3개의 스트립으로 구성되었다. 다양한 방법으로 실험을 수행한 결과에 따르면 유사성 측정 방법으로는 SNCC, 유사성 측정 요소로는 화소값과 화소값 기울기 강도 평균, 그리고 비정규 적응형 기준 윈도우가 수직궤적 기반 다중영상정합의 영역기반 유사성 측정에 가장 적합하다는 것을 확인하였다.