• 한국방사선학회논문지
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• 제9권6호
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• pp.403-408
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• 2015

경엑스선은 물체의 내부구조 관찰에 유용하고 의료 및 산업분야에 광범위하게 사용되고 있다. 전산화단층촬영기법은 수백장의 투영영상을 이용하여 재구성함으로써 물체의 2차원 단면 영상을 얻을 수 있다. 단면 영상의 품질은 투영영상에 크게 의존한다. 투영영상을 얻는 검출기의 픽셀에 따라 링 아티팩트가 나타난다. 본 연구는 visual C++기반으로 한 원형 팬텀에서 검출기의 검출 에러에 따른 링 아티팩트 비를 조사하였다. 평행빔 및 부채살빔에서 링 아티팩트 비는 검출기의 검출 에러에 비례하여 나타났고, 회전 중심에 가까울수록 링 아티팩트는 강하게 나타났다. 전산화단층촬영의 단면 영상에서 링 아티팩트를 줄이기 위해서는 영상재구성 이전에 검출기의 보정이 필요함을 알 수 있었다.

• Imaging Science in Dentistry
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• 제34권3호
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• pp.129-136
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• 2004

Purpose: To evaluate whether cone beam computed tomography can depict the distribution, position, frequency, relative vertical dimension, and the diameter of the lingual foramen and direction of lingual bone canal. Materials and Methods : Cone beam computed tomography of mandible was performed on 25 males and 25 females with no history of any orthodontic treatments or any other dental surgeries. A statistical comparison was done on the mean values of males and females. Results: In the location and distribution of lingual foramina, median lingual foramen was found in all subjects and lateral lingual foramen in 58%. In the lateral lingual foramen, bilateral type was found in 28% and unilateral type in 30%. In the number of lingual foramina, median lingual foramen had two foramina and lateral lingual foramen had one foramen, mostly. In the relative mean vertical dimension of lingual foramina, median lingual foramen was 0.03±0.08, and both lateral lingual foramina was 0.20±0.04. The mean diameter of lingual foramina, median lingual foramen was 0.9mm±0.28, right lateral lingual foramen was 0.92mm±0.23, and left lateral lingual foramen was 0.88mm±0.27. The most frequent direction of the lingual bone canals, median lingual bone canal proceeded in anteroinferior direction and lateral lingual bone canal in anterosuperolateral direction. Conclusion : Cone beam computed tomography can be helpful for surgery and implantation on the mandibular area. Radiologist should be aware of this anatomical feature and its possible implications.

• 대한소아치과학회지
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• 제25권3호
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• pp.493-498
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• 1998

1. CT에 의한 매복치의 위치결정은 적절한 치료계획의 수립을 가능하게 하여 시술시간의 단축과 인접치, 인접구조물의 손상을 줄여 시술후의 부작용을 줄일 수 있었다. 2. 매복된 영구치의 견인시 CR를 활용한 결과 개창부위의 정확한 위치결정과 예후에 대한 예측이 가능하였다. 3. 평면방사선사진의 판독후 악골내 병소가 의심되어 CT를 활용한 결과 병소의 확진이 가능하였다. 4. 소아의 CT촬영은 평면 방사선 촬영에 비해 증가된 방사선 피폭량, 높은 수가 때문에 적절한 증례의 선택이 중요하다.

• 전기전자학회논문지
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• 제23권3호
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• pp.768-776
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• 2019

4차 산업 혁명 시대를 맞이하여, 최근 기계, 전자 부품의 설계, 제조, 검사에 첨단 IT 기술을 융합하는 사례가 늘고 있다. 본 연구에서는 최근에 구축된 산업용 X-ray CT(computed tomography)를 사용한 산업용 부품의 검사에 대한 최신기술에 대해서 다룬다. 먼저 구축된 첨단의 최신 산업용 CT의 구조와 원리에 대해서 설명하며, 이러한 장비의 역할과 성능에 대해서 설명하고, 본 장비의 분석기법을 보완하기 위한 새로운 연구기반의 구축에 대해서 다룬다. 특히 장비의 출력데이터를 Matlab과 같은 범용 연구 툴로 전송하여 연구를 진행할 수 있는 기반을 구축하며, 이를 토대로 기존의 운용 소프트웨어가 제공하지 못했던 보조적인 3D user interface와 3차원 영상처리를 위한 플랫폼을 구축하는 연구를 진행 하였다. 산업용 3차원 X-ray는 아직 소개 된지 얼마 되지 않은 첨단의 고가의 장비로서 이를 활용할 연구의 종류와 내용이 매우 풍부한 주제로, 이러한 기초적인 연구기반은 추후의 보다 발전적인 연구를 위한 아주 유용한 토대가 될 것으로 판단된다.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.9-16
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• 2021

Purpose: The purpose of this study was to analyze the reliability of 7 panoramic radiographic signs for predicting proximity of the root apices of mandibular third molars to the mandibular canal using cone-beam computed tomography and to correlate these findings with the Pell and Gregory and the Winter classification systems. Materials and Methods: An observational, cross-sectional, descriptive study was conducted on 74 patients with bilateral impacted mandibular third molars. Four panoramic radiographic signs were observed in the tooth root (darkening, deflection, and narrowing of the root apices, and bifid apices), and another 3 in the mandibular canal (diversion, narrowing, and interruption of the mandibular canal). Cone-beam computed tomography images were analyzed to identify disruption and diversion of the mandibular canal and root deflection. Results: Binary logistic regression showed that only 4 of the 7 panoramic radiographic signs were able to predict proximity of the root apices of the mandibular third molars to the mandibular canal: darkening of the root, deflection of the root, narrowing of the root, and interruption of the mandibular canal(P<0.05). Conclusion: Darkening, deflection, and narrowing of the root, in tandem with the interruption of the mandibular canal on panoramic radiographs, indicate that cone-beam computed tomography should be performed when planning the extraction of impacted mandibular third molars. Proximity between mandibular third molars and the mandibular canal is correlated with the Winter classification.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.41-47
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• 2021

Purpose: This study aimed to compare the accuracy of 3-dimensional(3D) printed models derived from multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) systems with different fields of view (FOVs). Materials and Methods: Five human dry mandibles were used to assess the accuracy of reconstructions of anatomical landmarks, bone defects, and intra-socket dimensions by 3D printers. The measurements were made on dry mandibles using a digital caliper (gold standard). The mandibles then underwent MDCT imaging. In addition, CBCT images were obtained using Cranex 3D and NewTom 3G scanners with 2 different FOVs. The images were transferred to two 3D printers, and the digital light processing (DLP) and fused deposition modeling (FDM) techniques were used to fabricate the 3D models, respectively. The same measurements were also made on the fabricated prototypes. The values measured on the 3D models were compared with the actual values, and the differences were analyzed using the paired t-test. Results: The landmarks measured on prototypes fabricated using the FDM and DLP techniques based on all 4 imaging systems showed differences from the gold standard. No significant differences were noted between the FDM and DLP techniques. Conclusion: The 3D printers were reliable systems for maxillofacial reconstruction. In this study, scanners with smaller voxels had the highest precision, and the DLP printer showed higher accuracy in reconstructing the maxillofacial landmarks. It seemed that 3D reconstructions of the anterior region were overestimated, while the reconstructions of intra-socket dimensions and implant holes were slightly underestimated.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.93-98
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• 2021

meta-iodobenzylguanidine is one of the norepinephrine analogs and reuptakes together with norepinephrine with norepinephrine transporter. The radioiodinated ligand, ¹²³I-meta-iodobenzylguanidine, is the most widely used for single photon emission computed tomography imaging to diagnose functional abnormalities and tumors of the sympathetic nervous system. In this study, we performed cellular uptake studies of ¹²³I-meta-iodobenzylguanidine in positive- and negative-norepinephrine transporter cells in vitro to verify the uptake activity for norepinephrine transporter. After ¹²³I-meta-iodobenzylguanidine was injected via a tail vein into normal mice, Single photon emission computed tomography/computed tomography images were acquired at 1 h, 4 h, and 24 h post-injection, and quantified the distribution in each organ including the adrenal medulla as a norepinephrine transporter expressing organ. In vitro cell study showed that ¹²³I-meta-iodobenzylguanidine specifically uptaked via norepinephrine transporter, and significant uptake of ¹²³I-meta-iodobenzylguanidine in the adrenal medulla in vivo single photon emission computed tomography images. These results demonstrated that single photon emission computed tomography imaging with ¹²³I-meta-iodobenzylguanidine were able to quantify the biodistribution in vivo in the adrenal medulla in normal mice.

• Journal of Veterinary Science
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• 제24권5호
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• pp.65.1-65.9
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• 2023

Background: Bone subtraction computed tomography angiography (BSCTA) is a useful alternative technique for improving visualization of vessels surrounded by skull bone. However, no studies have compared computed tomography angiography (CTA) and BSCTA for improving the visibility of canine cerebral blood vessels. Objectives: To evaluate the potential benefit of BSCTA for better delineation of brain arteries of the circle of Willis (CoW) in dogs by comparing BSCTA with non-subtraction computed tomography angiography (NSCTA). Methods: Brain CTA was performed for nine healthy beagle dogs using a bolus tracking method with saline flushing. A total dose of 600 mgI/kg of contrast agent with an iodine content of 370 mgI/mL was injected at a rate of 4 ml/s. Bone removal was achieved automatically by subtracting non-enhanced computed tomography (CT) data from contrast CT data. Five main intracranial arteries of the CoW were analyzed and graded on a scale of five for qualitative evaluation. Results: Scores of basilar artery, middle cerebral artery, and rostral cerebral artery in the BSCTA group were significantly higher than those in the NSCTA group (p = 0.001, p = 0.020, and p < 0.0001, respectively). Scores of rostral cerebellar artery (RcA) and caudal cerebral artery (CCA) did not differ significantly between the two groups. However, scores of RcA and CCA in the BSCTA group were higher than those in the NSCTA group. Conclusions: BSCTA improved visualization of intracranial arteries of the CoW with close contact to bone. Thus, it should be recommended as a routine scan method in dogs suspected of having brain vessel disease.

• 대한수의학회지
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• 제52권3호
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• pp.205-208
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• 2012

Endocrine test data from a 13-year old intact female Maltese was indicative of the presence of an insulinoma, however ultrasonography identified a pancreatic mass only after 10 months after the first admission. Following identification of both pancreatic tumor and hepatic metastasis on computed tomography (CT), surgical excision of the mass was attempted. However, total excision failed because of tumor adhesion to adjacent large vessels. The pancreatic mass was monitored over the next 25 months via ultrasonography, CT, and positron emission tomography-computed tomography (PET-CT). Histopathological and immunohistochemical data confirmed the diagnosis of insulinoma with hepatic metastasis.

• Investigative Magnetic Resonance Imaging
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• 제20권4호
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• pp.259-263
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• 2016

Primary diffuse large B-cell lymphoma of the seminal vesicle is an extremely rare disorder, with only two cases reported in the English literature. Here, we present imaging findings of a case of primary diffuse large B-cell lymphoma of the seminal vesicle. On transrectal ultrasonography, the mass presented as a 3.0-cm-sized heterogeneous, hypoechoic lesion in the right seminal vesicle. Computed tomography (CT) revealed a mass with rim-like enhancement in the right seminal vesicle. On magnetic resonance imaging (MRI), the tumor showed iso-signal intensity on T1-weighted images and heterogeneously intermediate-high signal intensity on T2-weighted images. The tumor showed rim-like and progressive enhancement with non-enhancing portion on dynamic scanning. Diffusion restriction was observed in the mass. On fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) imaging, a high standardized uptake value (maxSUV, 23.5) by the tumor was noted exclusively in the right seminal vesicle.