• 대한방사선치료학회지
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• 제25권2호
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• pp.187-192
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• 2013

목 적: 좌측 유방암 환자 치료 시 4D-CT를 이용하여 기존에 호흡이 고려되지 않았던 치료와 비교하여 심장의 체적 변화와 호흡에 따른 심장의 선량 차이를 알아보고자 한다. 대상 및 방법: 2012년 3월부터 5월까지 본원에 내원한 2문 접선조사로 치료받은 좌측 유방암 환자 10명을 대상으로 하였다. 좌측 유방이 충분히 포함될 수 있도록 FOV (Field-of-view)를 설정하고 자유 호흡 상태의 일반 CT (Free-Breathing CT)와 4D-CT를 통해 영상을 획득하였다. 선량은 50.4 Gy (1.8 Gy/28 fraction)로 필요에 따라 추가적으로 계획용표적체적(PTV: Planning target volume)에 전자선 1문 조사 9 Gy (1.8 Gy/5 Fraction)를 처방하였고 선량체적히스토그람(Dose Volume Histogram)를 이용하여 심장에 받는 선량과 체적을 비교 분석하였다. 결 과: Free-Breathing CT 영상과 4D-CT 영상의 심장에 받는 선량과 체적을 비교 분석한 결과 4D-CT 영상에서 심장의 체적이 최대 40.5% 크게 나타났으며 또한 심장의 총 흡수선량도 최대, 최소, 평균선량이 최대 8.8%, 27.9%, 37.4% 높게 나타났다. 결 론: 4D-CT를 촬영하여 호흡을 고려한 치료계획이 Free-Breathing CT 영상으로 치료 계획한 것 보다 환자의 심장선량이 높게 조사된 것으로 나타났다. 따라서 심장과 근접한 좌측 유방 방사선치료 시 심장박동에 의한 심장의 체적변화를 고려한 치료계획을 세워야 할 것으로 사료된다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.506-508
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• 2002

As an advancement of medical imaging modalities and analyzing software with multi-function, active researches to acquire high contrast and high resolution image being done. In recently, development of medical imaging modalities like as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) is aiming to display anatomical structure more accuracy and faster. Thus, one of the important areas in CT today is the use of CT scanner for the quantitative evaluation of 3-D reconstruction images from 2-D tomographic images. In CT system, the effective slice thickness and the quality of 3-D reconstructed image will be influenced by imaging acquisition parameters (e.g. pitch and scan mode). In diagnosis and surgical planning, the accurate distance measurements of 3-D anatomical structures play an important role and the accuracy of distance measurements will depend on the acquisition parameters such as slice thickness, pitch, and scan mode. The skull phantom was scanned with SDCT for various acquisition parameters and acquisition slice thicknesses were 3 and 5 mm, and reconstruction intervals were 1, 2, and 3 mm to each pitch. 3-D visualizations and distance measurements were performed with PC based 3-D rendering and analyzing software. Results showed that the image quality and the measurement accuracy of 3-D SDCT images are independent to the reconstruction intervals and pitches.

• Imaging Science in Dentistry
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• 제42권1호
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• pp.25-33
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• 2012

Purpose : This study was performed to determine the accuracy of linear measurements on three-dimensional (3D) images using multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). Materials and Methods : MDCT and CBCT were performed using 24 dry skulls. Twenty-one measurements were taken on the dry skulls using digital caliper. Both types of CT data were imported into OnDemand software and identification of landmarks on the 3D surface rendering images and calculation of linear measurements were performed. Reproducibility of the measurements was assessed using repeated measures ANOVA and ICC, and the measurements were statistically compared using a Student t-test. Results : All assessments under the direct measurement and image-based measurements on the 3D CT surface rendering images using MDCT and CBCT showed no statistically difference under the ICC examination. The measurements showed no differences between the direct measurements of dry skull and the image-based measurements on the 3D CT surface rendering images (P>.05). Conclusion : Three-dimensional reconstructed surface rendering images using MDCT and CBCT would be appropriate for 3D measurements.

• 대한두개안면성형외과학회지
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• 제13권2호
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• pp.111-118
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• 2012

Purpose: The nasal bone fracture is known as the most common facial fracture, with the postoperative results and the patient's satisfaction known to be lower than other facial fractures. The patient's satisfaction is firstly related to the accurate comprehension of the spatial relationship in the fractured nasal bone and secondly to the accurate reduction based on accurate comprehension. The aim of this study is to evaluate the objective usefulness of the three-dimensional (3D) imaging. Methods: The survey was conducted on 10 randomly selected cases of nasal bone fractures among the 46 cases with 3D computed tomography (CT) during the past one year. It was requested upon 4 plastic residents and 4 plastic surgeons to draw 3D aspect of fractured nasal bone directly on the printed photos of cadaver nasal bone, based on simple X-ray and two-dimensional (2D) CT. They were compared with the real fractured nasal bone aspects based on the 3D image and marked the difference in the 10-point scale of 0 to 10. Results: The average score of the 4 residents was 1.62 and that of the 4 surgeons was 4.47 out of 10 by simple X-ray. The average score of the 4 residents was 5.67 and that of the 4 surgeons was 7.25 out of 10 by 2D CT. Conclusion: It was surmised that the precise analysis and accurate comprehension of the spatial relationship of the fractured nasal bone using the 3D image, as based on the 2D CT images, can produce more favorable satisfaction levels in the patients.

• Imaging Science in Dentistry
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• 제38권1호
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• pp.7-15
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• 2008

Purpose: This study provides comparative measurements of absorbed and effective doses for newly developed cone beam computed tomography (CT) in comparison with these doses for conventional CT. Materials and Methods: Thermoluminescent dosimeter rods (TLD rod: GR-200, Thermo Fisher Scientific Inc., Waltham, MA, USA) were placed at 25 sites throughout the layers of Male ART Head and Neck Phantom (Radiology Support Devices Inc., Long Beach, USA) for dosimetry. Implagraphy, DCT Pro (Vatech Co., Hwasung, Korea) units, SCT-6800TXL (Shimadzu Corp., Kyoto, Japan), and Crane x 3+(Soredex Orion Corp., Helsinki, Finland) were used for radiation exposures. Absorption doses were measured with Harshaw 3500TLD reader (Thermo Fisher Scientific Inc., Waltham, MA, USA). Radiation weighted doses and effective doses were measured and calculated by 2005 ICRP tissue weighting factors. Results: Absorbed doses in Rt. submandibular gland were 110.57 mGy for SCT 6800TXL (Implant), 24.56 mGy for SCT 6800TXL (3D), 22.39 mGy for Implagraphy 3, 7.19 mGy for DCT Pro, 5.96 mGy for Implagraphy 1, 0.70 mGy for Cranex 3+. Effective doses $(E_{2005draft)$ were 2.551 mSv for SCT 6800TXL (Implant), 1.272 mSv for SCT 6800TXL (3D), 0.598 mSv for Implagraphy 3, 0.428 mSv for DCT Pro and 0.146 mSv for Implagraphy 1. These are 108.6, 54.1, 25.5, 18.2 and 6.2 times greater than panoramic examination (Cranex 3+) doses (0.023mSv). Conclusion: Cone beam CT machines recently developed in Korea, showed lower effective doses than conventional CT. Cone beam CT provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

• 대한의용생체공학회:의공학회지
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• 제25권2호
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• pp.97-102
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• 2004

소 동물 촬영에 이용될 수 있는 고해상도의 x-선 cone-beam micro computed tomography (micro-CT) 시스템을 개발하였다 Micro-CT 시스템은 120${\times}$120 mm2 의 2차원 평판 x-선 감지기, micro-focus x-선 발생장치, 주사 기구부, 병렬처리 영상 재구성 시스템으로 이루어져 있다. 개발된 시스템의 성능을 평가하기 위해 대조도와 공간해상도를 측정하였다. 대조도 실험에서는 95 mGy 에서 36 CT-번호를 구별할 수 있음을 확인하였고, 공간 해상도 실험에서는 14 lp/mm 의 성능을 확인하였다. 소 동물 촬영 결과로 실험용 쥐의 대퇴부, 심장 그리고 복부 동맥 혈관을 촬영한 경상을 제시하였다. 개발된 micro-CT 시스템은 소 동물을 이용한 생명공학 분야 연구에 널리 이용될 수 있을 것으로 기대된다.

• Korean Journal of Radiology
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• 제22권3호
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• pp.435-441
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• 2021

Objective: To evaluate the usefulness of the ventricular volume percentage quantified using three-dimensional (3D) brain computed tomography (CT) data for interpreting serial changes in hydrocephalus. Materials and Methods: Intracranial and ventricular volumes were quantified using the semiautomatic 3D threshold-based segmentation approach for 113 brain CT examinations (age at brain CT examination ≤ 18 years) in 38 patients with hydrocephalus. Changes in ventricular volume percentage were calculated using 75 serial brain CT pairs (time interval 173.6 ± 234.9 days) and compared with the conventional assessment of changes in hydrocephalus (increased, unchanged, or decreased). A cut-off value for the diagnosis of no change in hydrocephalus was calculated using receiver operating characteristic curve analysis. The reproducibility of the volumetric measurements was assessed using the intraclass correlation coefficient on a subset of 20 brain CT examinations. Results: Mean intracranial volume, ventricular volume, and ventricular volume percentage were 1284.6 ± 297.1 cm³, 249.0 ± 150.8 cm³, and 19.9 ± 12.8%, respectively. The volumetric measurements were highly reproducible (intraclass correlation coefficient = 1.0). Serial changes (0.8 ± 0.6%) in ventricular volume percentage in the unchanged group (n = 28) were significantly smaller than those in the increased and decreased groups (6.8 ± 4.3% and 5.6 ± 4.2%, respectively; p = 0.001 and p < 0.001, respectively; n = 11 and n = 36, respectively). The ventricular volume percentage was an excellent parameter for evaluating the degree of hydrocephalus (area under the receiver operating characteristic curve = 0.975; 95% confidence interval, 0.948-1.000; p < 0.001). With a cut-off value of 2.4%, the diagnosis of unchanged hydrocephalus could be made with 83.0% sensitivity and 100.0% specificity. Conclusion: The ventricular volume percentage quantified using 3D brain CT data is useful for interpreting serial changes in hydrocephalus.

• Journal of International Society for Simulation Surgery
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• 제1권1호
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• pp.41-44
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• 2014

The aim of this report is showing the case that we could give exact navigation of perigastric vessels for gastrectomy with 3D CTA. A 74-year-old male patient visited hospital with gastric cancer. Early gastric cancer, type IIb was found at stomach antrum great curvature side. Before surgery, he underwent 3D CT angiography. 3D volume rendering images and MIP images were made by post processing. He had replaced Lt. hepatic artery arising from Lt. gastric artery. Surgeon could get patient's specific vascular anatomy before surgery including surgically relevant anatomical distance and direction and could finish gastrectomy within 4 hours and just 53ml blood loss.

• 대한두개안면성형외과학회지
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• 제10권2호
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• pp.103-108
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• 2009

Purpose: Although there are many reports on the development of paranasal sinuses, few studies were performed with respect to the frontal sinus with 3D CT, especially in Korean children. In this study, we evaluated the normal development of frontal sinus in Korean children with 3D CT imaging. Methods: A total of 301 patients under the age of 20 were reviewed retrospectively. Maximal AP (anteroposterior) length, height and width were measured with the aid of computer device. The volume of frontal sinus was also evaluated. Results: At the age of more than 4, the pneumatization of frontal sinus was detected. Frontal sinus developed continuously and was observed in almost every children at the age of more than 17. The AP length, height, width and volume of frontal sinus were enlarged continuously until the age of 20. And the maximal growth of frontal sinus was observed at puberty. The width and volume of frontal sinus showed high correlation coefficient (r=0.8) relative to height or AP distance. Conclusion: The results of this study may be helpful in the comprehension of normal development of frontal sinus in Korean children.

• 대한방사선기술학회지:방사선기술과학
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• 제37권3호
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• pp.203-209
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• 2014

쇄골 CT 영상을 이용하여 보급형 3D 프린터로 제작된 모델로 사전 수술계획을 실시하여 수술효율에 대한 유용성과 임상적 활용가능성을 평가하였다. CT 영상을 Open Source DICOM Viewer Osirix에서 STL 파일로 변환하여 FDM 와이어 척층가공방식의 보급형 3D 프린터로 환자 맞춤형 쇄골 골절 모델을 제작하였다. 또한, 인체의 좌우 대칭 특성을 이용하여 골절되지 않은 반대편 쇄골의 STL 파일을 Mirror 기법으로 손상되기 전 원형의 모델을 복원, 제작하였다. 모델은 골절의 위치와 크기, 정도가 동일하게 출력되었다. 영상의학과에서 적은 비용과 시간으로 직접 제작한 쇄골 모델을 활용하면 수술시 2차 손상을 줄이고, 최소 침습적 피하금속판 골유합술(MIPO)로 수술효율을 높일 수 있어 임상적으로 유용할 것으로 생각된다.