• 디지털융복합연구
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• 제12권3호
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• pp.367-375
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• 2014

본 연구는 실시간 동적영상(Real-time dynamic image)을 획득할 수 있는 고해상도 엑스선 영상장치인 마이크로 CT 을 이용하여 흰쥐의 미세 혈관구조를 관찰함은 물론 국내 원광 방사선영상 과학연구 센터에서 개발한 마이크로 CT 에 대한 유용성을 알아보고자 한다. 흰쥐 몸 전체의 2D 영상을 얻은 후 MIP(maximum intensity projection), VRT(volume rendering technique)기법을 이용하여 혈관구조의 조영된 3D 영상을 얻을 수 있었고 이 3D 혈관 영상을 머리, 복부, 심장과 몸 전체의 혈관시스템으로 각각 분류하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.923-926
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• 2005

To investigate the relationship between BMD, micro-structural and mechanical properties in intertrochanteric trabecular bone, the PIXI-mus2 system, micro-CT and FE model were used. The purpose of this study were (1) to apply high-resolution imaging techniques (micro-CT imaging) in combination with new computer modeling techniques (FEA) to quantify 3D microstructural and biomechanical properties of trabecular bone in the intertrochanteric region, and (2) determine if the prediction of bone elastic constant can be improved with structural index.

• The Journal of Advanced Prosthodontics
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• 제8권2호
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• pp.101-109
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• 2016

PURPOSE. To investigate the void parameters within the resin cements used for fiber post cementation by micro-CT (${\mu}CT$) and regional push-out bonding strength. MATERIALS AND METHODS. Twenty-one, single and round shaped roots were enlarged with a low-speed drill following by endodontic treatment. The roots were divided into three groups (n=7) and fiber posts were cemented with Maxcem Elite, Multilink N and Superbond C&B resin cements. Specimens were scanned using ${\mu}CT$ scanner at resolution of $13.7{\mu}m$. The number, area, and volume of voids between dentin and post were evaluated. A method of analysis based on the post segmentation was used, and coronal, middle and apical thirds considered separately. After the ${\mu}CT$ analysis, roots were embedded in epoxy resin and sectioned into 2 mm thick slices (63 sections in total). Push-out testing was performed with universal testing device at 0.5 mm/min cross-head speed. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests (${\alpha}=.05$). RESULTS. Overall, significant differences between the resin cements and the post level were observed in the void number, area, and volume (P<.05). Super-Bond C&B showed the most void formation ($44.86{\pm}22.71$). Multilink N showed the least void surface ($3.51{\pm}2.24mm^2$) and volume ($0.01{\pm}0.01mm^3$). Regional push-out bond strength of the cements was not different (P>.05). CONCLUSION. ${\mu}CT$ proved to be a powerful non-destructive 3D analysis tool for visualizing the void parameters. Multilink N had the lowest void parameters. When efficiency of all cements was evaluated, direct relationship between the post region and push-out bonding strength was not observed.

• 대한토목학회논문집
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• 제44권2호
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• pp.141-147
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• 2024

본 연구에서는 마이크로 CT 이미지를 활용하여 3D 프린팅 콘크리트의 공극분포 특성에 따른 인장파괴 강도를 확인하였다. 3D 프린팅 기법으로 출력된 콘크리트 구조물은 일반적인 시편과는 다르게 적층방향 및 필라멘트 접촉면의 존재에 따라 공극의 방향성을 갖는다. 이에 따라 3D 프린팅 콘크리트 시편의 공극분포를 확률론적 방법으로 분석하고, 유한요소기법을 통해 방향별 인장강도를 분석하였다. 3D 프린팅된 시편 내부의 공극이 방향성을 갖는 것을 확인하였고, 출력에 의한 미세구조 특성-강도의 영향성을 평가하였다. 본 연구는 마이크로 CT 이미지 기반의 공극 분포 특성을 분석하고 시뮬레이션을 활용한 기계적 물성 평가를 수행하여 보다 향상된 성능의 적층 구조물 설계 및 재료 개발에 활용하고자 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.

• Restorative Dentistry and Endodontics
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• 제41권1호
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• pp.29-36
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• 2016

Objectives: The purpose of this study was to assess the ability of two new calcium silicate-based pulp-capping materials (Biodentine and BioAggregate) to induce healing in a rat pulp injury model and to compare them with mineral trioxide aggregate (MTA). Materials and Methods: Eighteen rats were anesthetized, cavities were prepared and the pulp was capped with either of ProRoot MTA, Biodentine, or BioAggregate. The specimens were scanned using a high-resolution micro-computed tomography (micro-CT) system and were prepared and evaluated histologically and immunohistochemically using dentin sialoprotein (DSP). Results: On micro-CT analysis, the ProRoot MTA and Biodentine groups showed significantly thicker hard tissue formation (p < 0.05). On H&E staining, ProRoot MTA showed complete dentin bridge formation with normal pulpal histology. In the Biodentine and BioAggregate groups, a thick, homogeneous hard tissue barrier was observed. The ProRoot MTA specimens showed strong immunopositive reaction for DSP. Conclusions: Our results suggest that calcium silicate-based pulp-capping materials induce favorable effects on reparative processes during vital pulp therapy and that both Biodentine and BioAggregate could be considered as alternatives to ProRoot MTA.

• Imaging Science in Dentistry
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• 제45권4호
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• pp.205-211
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• 2015

Purpose: This study was performed to compare the accuracy of micro-computed tomography (CT) and cone-beam computed tomography (CBCT) in detecting accessory canals in primary molars. Materials and Methods: Forty-one extracted human primary first and second molars were embedded in wax blocks and scanned using micro-CT and CBCT. After the images were taken, the samples were processed using a clearing technique and examined under a stereomicroscope in order to establish the gold standard for this study. The specimens were classified into three groups: maxillary molars, mandibular molars with three canals, and mandibular molars with four canals. Differences between the gold standard and the observations made using the imaging methods were calculated using Spearman's rho correlation coefficient test. Results: The presence of accessory canals in micro-CT images of maxillary and mandibular root canals showed a statistically significant correlation with the stereomicroscopic images used as a gold standard. No statistically significant correlation was found between the CBCT findings and the stereomicroscopic images. Conclusion: Although micro-CT is not suitable for clinical use, it provides more detailed information about minor anatomical structures. However, CBCT is convenient for clinical use but may not be capable of adequately analyzing the internal anatomy of primary teeth.

• 대한소아치과학회지
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• 제48권3호
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• pp.352-358
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• 2021

Molar-incisor malformation (MIM)은 치관은 정상이나 치근의 비정상적인 형태를 보이는 것이 특징적이다. 제1대구치에 가장 많이 발생하며, 제2유구치나 상악 중절치도 때때로 이환된다. 이 증례 보고에서는 제1대구치를 포함해, 제2유구치에 MIM이 나타난 환자의 증례를 보고하고, 치근이 건전하게 발거된 제2유구치의 micro computed tomography (CT)를 이용한 형태학적 분석을 시행하였다. 발거된 치아에서는 MIM의 외형적 특징인 치관 - 치근 이행부의 cervical constriction을 육안상으로 확인할 수 있었으며, micro CT 분석에서 백악법랑경계부의 광화된 부위 (Cervical Minelarized Diaphragm), 많은 부근관과 막힌 근관 등의 복잡한 근관 형태, 근관 내 석회화 물질, 영구치에 비해 상대적으로 협착된 치관부 치수강이 관찰되었다.

• 대한토목학회논문집
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• 제43권1호
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• pp.1-7
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• 2023

서로 다른 밀도를 가진 기포콘크리트 시편을 생성하고, 각 시편의 특성을 SEM, micro-CT 등의 미세구조 분석 방법을 활용하여 분석하였다. 서로 다른 재령 일자에 대한 기포콘크리트 시편의 공극과 고체 구조를 분석함으로써, 재령 기간이 재료 특성 변화에 미치는 영향을 살펴보았다. 각 기포콘크리트 시편의 압축강도와 열전도도를 측정하여, 재료 물성과 미세구조적 특성 간의 상관관계에 대하여 분석하였으며, 결과를 통해 밀도와 재령 기간이 재료 강도에 미치는 영향을 확인하였다.

• 한국콘텐츠학회논문지
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• 제10권9호
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• pp.259-266
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• 2010

고해상도 엑스선 영상장치인 마이크로 CT를 이용, 흰쥐 간의 전체적인 문맥상과 각 간엽(lobe)의 미세혈관구조를 관찰하여 4개 분절 간엽의 구조를 영상화 하였고, 단축면상의 데이터를 3D영상으로 재구성한 미세혈관 구조의 입체적인 영상을 획득할 수 있는 마이크로 CT에 대한 유용성을 알아보고자 하였다. 5마리의 간 중에서 손상이 가장 적은 1개의 간을 4 개의 분절 간엽으로 각각 절단하여 문맥의 미세구조를 이차원으로 구성하였으며, MIP기법을 이용하여 간 문맥 전체 미세혈관의 3D영상을 얻었으며, 각 간엽의 미세혈관은 6분지까지 관찰할 수 있었다. 6 분지까지의 크기를 측정한 결과 평균치는 1 branch : $0.51mm{\pm}0.08$, 2 branch : $0.32mm{\pm}0.12$, 3 branch : $0.23mm{\pm}0.11$, 4 branch : $0.19 mm{\pm}0.08$, 5 branch : $0.13mm{\pm}0.06$, 6 branch : $70.5{\mu}m{\pm}14.1$ 로 측정되었다. 본 연구의 실험 결과에서 획득한 3차원의 입체 영상과 미세혈관 구조의 발견은 향후 고해상력의 영상을 얻을 수 있는 마이크로 CT가 많이 이용될 수 있을 것으로 기대된다.