• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.211-212
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• 2021

This study was conducted to derive quantitative air void volume calculation techniques in various complexes with porosity. Calculation of voids in a complex is an essential factor in improving mechanical properties, and quantitative measurement techniques are needed because the environment is not constant to apply the currently used ASTM criteria. Using the analysis technique obtained through 2D image analysis, it is believed that meaningful results can be derived through Micro CT analysis results and cross-check later.

• 핵의학기술
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• 제18권1호
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• pp.127-133
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• 2014

PET/CT에서 환자피폭 문제로 인해 저 선량의 중요성이 강조되고 있다. 본 연구에서는 기존에 사용되던 CT 데이터를 이용한 감쇠보정법인 CTAC와 새롭게 적용된 Q.AC를 환자실험과 팬텀 실험을 통해 저 선량으로 촬영 시 PET 영상에 미치는 영향에 대해 알아보고자 한다. 실험장비는 GE사의 PET/CT Discovery 710 (GE Healthcare, USA)를 사용하였으며 팬텀실험으로 감쇠보정의 정량적 평가를 위한 NEMA IEC body phantom과 균일성 평가를 위한 Uniform NU2-94 phantom을 사용하였다. 각각의 팬텀 내부에 동위원소 18-F FDG를 70.78 MBq, 22.2 MBq 주입하고 CT조건은 저 선량조건으로 80 kVp, 10 mA로부터 일반선량 조건으로 140 kVp, 120 mA 조건까지 스캔 후 CTAC와 Q.AC 두 감쇠보정법을 적용하여 재구성하였다. PET 영상에서 일반선량 조건을 기준값으로 정하고 horizomtal profile과 vertical profile을 통해 정량평가를 시행하고 기준값과의 상대적 오차를 평가하였다. 또한 환자실험으로 정상체중 환자와 과체중 환자를 구분하여 저 선량과 일반선량으로 비교 촬영한 뒤 CTAC와 Q.AC로 재구성된 PET영상에서 주요장기별 SUV에 대한 상대적 오차와 신호 대 잡음비를 비교분석하였다. 팬텀실험 결과 저선량 조건에서 CTAC와 Q.AC로 각각 재구성한 PET 영상의 profile과 상대적 오차에서 CTAC보다 Q.AC가 기준값과의 오차가 적은 그래프를 얻었다. 환자실험의 경우 일반선량 조건에서는 정상체중 환자와 과체중 환자 모두 감쇠보정법에 따른 상대적 오차값의 변화가 적었으나 저 선량 조건에서는 정상체중 환자보다 과체중 환자에서 감쇠보정법의 변경에 의한 상대적 오차의 감소폭이 커짐으로 기준값과 차이가 감소하였다. 기존의 감쇠보정법인 CTAC는 80 kVp, 10 mA의 저선량 CT를 사용하는데 있어 PET 영상의 선속경화현상이 발생한다. 이로 인해 CTAC를 이용하여 재구성된 PET 데이터는 정량화하는데 문제가 될 수 있음을 확인했다. 반면에 새로운 알고리즘이 적용된 Q.AC는 과체중 환자의 경우 80 kVp, 10 mA 정도까지는 140 kVp, 120 mA 조건으로 촬영하여 재구성한 PET 데이터 결과와 차이가 적음을 확인할 수 있었다. Q.AC를 이용한 경우 기존보다 저 선량의 CT를 이용해 PET의 재구성에 이용할 수 있으므로 환자의 피폭을 줄이는 데 큰 역할을 할 것으로 기대한다.

• 핵의학기술
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• 제28권1호
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• pp.41-47
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• 2024

Purpose: ¹⁸F-FET, a radiopharmaceutical based on a Tyrosine amino acid derivative using the Sodium-Potassium Pump-independent Transporter (System L) for non-invasive evaluation of primary, recurrent, and metastatic brain tumors, exhibits distinct characteristics. Unlike the widely absorbed ¹⁸F-FDG in both tumor and normal brain tissues, ¹⁸F-FET demonstrates specific uptake only in tumor tissue while almost negligible uptake in normal brain tissue. This study aims to compare and evaluate the usefulness of ¹⁸F-FDG and ¹⁸F-FET Brain PET/CT quantitative analysis in brain tumor diagnosis. Materials and Methods: In 46 patients diagnosed with brain gliomas (High Grade: 34, Low Grade: 12), Brain PET/CT scans were performed at 40 minutes after ¹⁸F-FDG injection and at 20 minutes (early) and 80 minutes (delay) after ¹⁸F-FET injection. SUV_max and SUV_peak of tumor areas corresponding to MRI images were measured in each scan, and the SUV_max-to-SUV_peak ratio, an indicator of tumor prognosis, was calculated. Differences in SUV_max, SUV_peak, and SUV_max-to-SUV_peak ratio between ¹⁸F-FDG and ¹⁸F-FET early/delay scans were statistically verified using SPSS (ver.28) package program. Results: SUV_max values were 3.72±1.36 for ¹⁸F-FDG, 4.59±1.55 for ¹⁸F-FET early, and 4.12±1.36 for ¹⁸F-FET delay scans. The highest SUV_max was observed in ¹⁸F-FET early scans, particularly in HG tumors (4.85±1.44), showing a slightly more significant difference (P<0.0001). SUV_peak values were 3.33±1.13 for ¹⁸F-FDG, 3.04±1.11 for ¹⁸F-FET early, and 2.80±0.96 for ¹⁸F-FET delay scans. The highest SUV_peak was in ¹⁸F-FDG scans, while the lowest was in ¹⁸F-FET delay scans, with a more significant difference in HG tumors (P<0.001). SUV_max-to-SUV_peak ratio values were 1.11±0.09 for ¹⁸F-FDG, 1.54±0.22 for ¹⁸F-FET early, and 1.48±0.17 for ¹⁸F-FET delay scans. This ratio was higher in ¹⁸F-FET scans for both HG and LG tumors (P<0.0001), but there was no statistically significant difference between ¹⁸F-FET early and delay scans. Conclusion: This study confirms the usefulness of early and delay scans in ¹⁸F-FET Brain PET/CT examinations, particularly demonstrating the changes in objective quantitative metrics such as SUV_max, SUV_peak, and introducing the SUV_max-to-SUV_peak ratio as a new evaluation metric based on the degree of tumor malignancy. This is expected to further contributions to the quantitative analysis of Brain PET/CT images.

• 대한방사선기술학회지:방사선기술과학
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• 제31권1호
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• pp.71-81
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• 2008

CT 영상은 커널의 종류와 재구성 방법에 따라 다양하게 나타나며, 관심 영역의 CT감약계수 및 노이즈는 정밀도에 영향을 준다. 커널의 종류에 따른 노이즈, 공간분해능 및 MTF를 측정하여 영상을 평가하였다. 다중채널CT 스캐너를 이용하여 팬텀 및 복부를 스캔 하였고, 커널은 B10(very smooth), B20(smooth), B30(medium smooth), B40(medium), B50(medium sharp), B60(sharp), B70(very sharp), B80(ultra sharp)으로 재구성하여 물, 공기, 간의 실질 조직, 근육, 지방 부위를 ROI 기능을 이용하여 평균의 CT감약계수와 표준편차인 노이즈를 정량적으로 측정하여 영상을 비교하였다. 그 결과CT 감약계수는 물($1.1{\sim}1.8\;HU$), 공기($-998{\sim}-1,000\;HU$)이고, 물에서의 노이즈($5.4{\sim}44.8\;HU$), 공기($3.6{\sim}31.4\;HU$)이다. 인체에서 간 실질 조직과 지방, 근육의 CT 감약계수와 노이즈를 커널에 따라 측정하였다. 지방의 CT 감약계수($-2.2{\sim}0.8\;HU$), 간의 실질 조직에서 CT감약계수($60.4{\sim}62.2\;HU$), 노이즈($7.6{\sim}63.8\;HU$), 근육의 CT감약계수($53.3{\sim}54.3\;HU$), 노이즈($10.4{\sim}70.7\;HU$) 사이에서 분포하였고, 커널이 높아질수록 노이즈도 증가하였다. 영상의 질을 높이기 위해서는 검사부위에 따라 노이즈를 감소하기 위해 적절한 커널을 선택하여 CT 검사를 하여야 한다.

• Journal of Periodontal and Implant Science
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• 제48권4호
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• pp.202-212
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• 2018

Purpose: Bone-to-implant contact (BIC) is difficult to measure on micro-computed tomography (CT) because of artifacts that hinder accurate differentiation of the bone and implant. This study presents an advanced algorithm for measuring BIC in micro-CT acquisitions using a spiral scanning technique, with improved differentiation of bone and implant materials. Methods: Five sandblasted, large-grit, acid-etched implants were used. Three implants were subjected to surface analysis, and 2 were inserted into a New Zealand white rabbit, with each tibia receiving 1 implant. The rabbit was sacrificed after 28 days. The en bloc specimens were subjected to spiral (SkyScan 1275, Bruker) and round (SkyScan 1172, SkyScan 1275) micro-CT scanning to evaluate differences in the images resulting from the different scanning techniques. The partial volume effect (PVE) was optimized as much as possible. BIC was measured with both round and spiral scanning on the SkyScan 1275, and the results were compared. Results: Compared with the round micro-CT scanning, the spiral scanning showed much clearer images. In addition, the PVE was optimized, which allowed accurate BIC measurements to be made. Round scanning on the SkyScan 1275 resulted in higher BIC measurements than spiral scanning on the same machine; however, the higher measurements on round scanning were confirmed to be false, and were found to be the result of artifacts in the void, rather than bone. Conclusions: The results of this study indicate that spiral scanning can reduce metal artifacts, thereby allowing clear differentiation of bone and implant. Moreover, the PVE, which is a factor that inevitably hinders accurate BIC measurements, was optimized through an advanced algorithm.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권1호
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• pp.49-56
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• 2010

Objective: To evaluate nasal and upper lip changes after Le Fort I surgery by means of images taken with a three-dimensional computed tomography (3D-CT). Methods: Fifteen patients (9 female and 6 male, mean age 21.9 years) with preoperative and postoperative 3D-CT were studied. The patients underwent maxillary movement with impaction or elongation, and advancement or setback. With the 3D-CT which presents reconstructive soft tissue images, preoperative and postoperative measurement and analysis were performed for nasal tip projection angle, columellar angle, supratip break angle, nasolabial angle, interalar width, internostril width, columella length and nasal tip projection. Results: Postoperative interalar and internostril widening was significant for all categories of maxillary movement. However, there was little significant relation in all parameters between the amount and direction of maxillary movement. Interestingly, movement of the maxilla with upward did show a little decrease in the columellar angle, supra tip break angle and nasolabial angle. Also movement of the maxilla with forward did show a little advancement in the upper lip position. Conclusion: Changes to the nose clearly occur after orthognathic surgery. There was a significant increase in postoperative interalar width and internostril width with maxillary movement. However, no clear correlation could be determined between amount of change and maxillary movement. Interestingly, maxillary impaction did show a little decrease in the columellar angle, supra tip break angle and nasolabial angle. In addition, we used 3D-CT for more precise analysis as a useful tool.

• Biomolecules & Therapeutics
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• 제23권2호
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• pp.195-200
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• 2015

We tested the hypothesis that micro-computed tomography (micro-CT) analysis provides a better quantitative readout of the therapeutic potential of methotrexate (MTX) for treating collagen-induced arthritis (CIA) in rats and compared to conventional histopathological examination. Rats were divided into three groups: Group 1 (G1) was treated with 0.9% saline, whereas groups 2 (G2) and 3 (G3) were boosted with type II collagen at days 0 and 7. Following the first collagen immunization, rats in G1 and G2 were treated with 0.9% saline and those in G3 were treated with 1.5 mg/kg MTX from day 14 to 28. All rats were sacrificed on day 28, at which point and all hind knee joints were analyzed by micro-CT and histopathological examination. Micro-CT analyses showed that bone volume and trabecular number were significantly decreased in G2 and G3 compared to G1 (p<0.01), as was percent bone volume (p<0.05 and p<0.01, respectively). However, bone surface/bone volume was significantly increased in G2 and G3 compared to G1 (p<0.05 and p<0.01, respectively). Trabecular separation was significantly increased in G3 compared to G1 (p<0.05). Histopathological examination showed that knee joints of rats in G2 and G3 showed severe joint destruction with inflammatory cell infiltration. However, cartilage destruction was slightly reduced in G3 compared to G2. Taken together, these results suggest that MTX treatment reduced cartilage destruction in rats with CIA, and micro-CT analyses made it possible to quantify arthritic bony lesion.

• Journal of Korean Neurosurgical Society
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• 제59권6호
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• pp.544-550
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• 2016

Objective : Cerebral endothelial cells have unique biological features and are fascinating candidate cells for stroke therapy. Methods : In order to understand the molecular mechanisms of human cerebral endothelial cell (hCMEC/D3) transplantation in a rat stroke model, we performed proteomic analysis using 2-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Protein expression was confirmed by quantitative real-time PCR and Western blot. Results : Several protein spots were identified by gel electrophoresis in the sham, cerebral ischemia (CI), and CI with hCMEC/D3 treatment cerebral ischemia with cell transplantation (CT) groups, and we identified 14 differentially expressed proteins in the CT group. Proteins involved in mitochondrial dysfunction (paraplegin matrix AAA peptidase subunit, SPG7), neuroinflammation (peroxiredoxin 6, PRDX6), and neuronal death (zinc finger protein 90, ZFP90) were markedly reduced in the CT group compared with the CI group. The expression of chloride intracellular channel 4 proteins involved in post-ischemic vasculogenesis was significantly decreased in the CI group but comparable to sham in the CT group. Conclusion : These results contribute to our understanding of the early phase processes that follow cerebral endothelial cell treatment in CI. Moreover, some of the identified proteins may present promising new targets for stroke therapy.

• Archives of Plastic Surgery
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• 제32권4호
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• pp.467-473
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• 2005

Calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized and accepted as a standard procedure. One of the commonly reported problems of calvarial bone graft is the contour defect caused by partial resorption of the graft. But, there are few reports that discuss the fate of the calvarial bone graft based on the quantitative data. In this article, the changes of grafted calvarial bone were evaluated using 3-dimensional computed tomography(CT). 9 patients were observed with the CT scans at 2mm thickness immediately after operation and at the time of last follow-up. The area of the bone defect was segmented on the 3-dimensional CT image and calculated by AnalyzeDirect 5.0 software. The immediate postoperative bone defect area of the recipient site and the donor site were $612.9mm^2$ and $441.5mm^2$, respectively, which became $1028.1mm^2$ and $268.8mm^2$, respectively at the last follow-up. In conclusion, the bone defect area was less increased on the donor site of calvarial bone graft than on the recipient site. And the CT scan is a valuable imaging method to assess and follow-up the clinical outcome of calvarial bone grafting.

• 한국발생생물학회지:발생과생식
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• 제14권4호
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• pp.261-268
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• 2010

As in the O. mykiss electrophoretic profiles of RNA, the signals of each RNA sample from 9 individual tissues such as liver, muscle, brain, heart, pituitary gland, kidney, intestine, spleen and gill similar to positive control were obtained. The tissue distributions of the complimentary DNA (cDNA) of O. mykiss four genes were analyzed using quantitative real-time PCR with primer sets for tissue expression analysis. In this rainbow trout species, author obtained bands of various sizes, ranged from 700 bp to 1,400 bp. A dissociation curve was made at the end of each run to make sure that there was no non-specific amplification. Supplementarily, the Ct of each DNA was compared. The Ct values of vinculin with rainbow trout tissues were determined in a manner similar to those for agouti-related protein (AgRP) and melanocortin receptors (MC4R I and MC4R II). Further, obtained Cts for standard curve of each DNA were affected by specific product (vinculin, AgRP and MC4R II genes). After several experiments with four individual genes of rainbow trout, author estimated a variation ratio of the mean Ct value of the DNA extracted using the comparative CTt method was 37.27, and the standard deviation was 5.33. The correlation coefficient between the Ct values and the concentration of cDNA was -0.98, -0.99, -0.91 and -0.86, respectively (vinculin, AgRP, MC4R I and MC4R II genes). Since this correlation showed high linearity, the straight line obtained was used as a standard for the O. mykiss tissues reared in aquarium. A PCR efficiency of 100% is ideally achieved when the slopes are close to the theoretical value of -3.31. According to quantification method, the results of quantification are strongly affected by the DNA fragmentation. The size of most DNA fragments obtained from various tissues of rainbow trout used in the experiment was approximately 100 bp. According to the four slopes, an efficiency of nearly 100% was estimated for four genes detection methods. Additionally, further analysis with more individuals and primers will be required to fully establish optimization in rainbow trout.