• 산업기술연구
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• 제23권A호
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• pp.63-68
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• 2003

Non-destructive method by tomography for safety diagnosis of civil engineering and building structures is tried. There are traveltime tomography that uses traveltime and fullwave tomography that uses the initial shock and seismic amplitude. But these methods have difficulty and weak points in accuracy and selection of initial value. In this study, corrected inversion method which is able to solve the two difficulty and this method is applied to theoretical pier model to calculate tomography.

• Imaging Science in Dentistry
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• 제32권2호
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• pp.67-73
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• 2002

Purpose: To examine the possible relationship between condylar position and disk displacement in the temporomandibular joint. Materials and Methods: 79 temporomandibular joints in 40 patients having temporomandibular disorders were classified into three categories: no disk displacement (NDD) , disk displacement with reduction (DDWR), and disk displacement without reduction (DDWOR). Disk positions were assessed from clinical and MRI findings. The relationship between the three categories and condylar positions was evaluated using lateral individualized corrected tomography. Results: Clinical findings regarding the relationship between condyle and disk positions having anterior, centric, and posterior positions were 27%, 27%, and 46%, respectively, in NDD, 43%, 17%, and 40%, respectively, in DDWR, and 44%, 22%, and 34%, respectively, in DDWOR. There were no significant differences in condylar positions between each of the groups (P>0.05). In the relationship between condyle and disk positions with MRI findings, anterior, centric, and posterior positions were 38%, 38%, and 24%, respectively, in NDD, 29%, 21%, and 50%, respectively, in DDWR, and 44%, 9%, and 47% respectively, in DDWOR. There were significant differences in the condylar positions when MRI was utilized (P<0.05) Conclusion: There was a significant correlation between the condyle and disk positions with MRI findings on lateral individualized corrected tomography.

• 대한치과교정학회지
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• 제24권3호
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• pp.587-620
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• 1994

This study was aimed to evaluate the changes in condylar position when severe anterior open bite patients were treated with MEAW. The subjects consisted of 11 patients(21 TMJs) who visited the departement of orthodontics in SNUH, having severe anterior open bite as a chief complain. They were supposed to wear the up and down elastics and MEAW after finishing the leveling. The condylar position was evaluated with individualized corrected tomography in centric occlusion taken before and after treatment. The results were as follows; 1. In the change of condylar position after treatment, there were no statistically significant differences in right and left TMJs. 2. In the change of condylar position after treatment, there were no statistically significant differences in each malocclusion groups. 3. There were no statistically significant differences in percent dispacement of condyle between before and after treatment 4. There were no statistically significant differences in the amount of change in condylar change.

• 산업기술연구
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• 제24권B호
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• pp.163-170
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• 2004

In this study, First, the results of travel-time inversion (first arrival inversion using the travel-time of the first arrival) were compared with those of full-wave inversion for numerical data. Numerical experiments to find key parameters other than initial velocity model showed that the frequency of source has a great effect on the result of full-wave inversion. Finally, this research presented the corrected full-wave inversion applying the correction term to the final result of full-wave inversion. The corrected full-wave inversion depicted cavities inside concretes even when the inversion started with 20% error in an initial velocity model for cavities. However, full-wave inversion did not reveal cavities.

• 한국의학물리학회지:의학물리
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• 제4권2호
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• pp.19-25
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• 1993

연구목적 : Lang cancer의 치료계획에서 내부 장기 밀도의 입력에 의한 선량보정 및 선량분포를 확인할 수 있는 CT planning과 contour CT image만으로 planning한 경우의 치료 계획을 비교 검토하여 치료선량의 차이, 치료면적의 교정, 선량의 loading의 교정을 통한 CT planning의 우수성을 밝히고자 한다. 대상 및 방법 : 영남대학교 치료방사선과에서 1990년 4월 1일 부터 1993년 8월 31일까지 방사선 치료한 폐암환자 87명을 대상으로 Contour나 CT image만을 사용한 치료 계획과 밀도를 입력한 CT를 받은 치료계획에서의 총선량과 선량분포등을 비교 검토하였다. 결과 : 폐암환자 87명 전원, Contour와 CT를 이용한 선량비교에서, Contour로 한 경우가 CT로 한 경우보다 높게 나타났으며, 선량 차이가 5%이하인 경우가 45명(52%), 5%에서 10%이하인 경우가 25명(29%), 10%에서 15%이하인 경우가 15명(17%), 15%이상인 경우가 2명(2%)으로 나타나서 45명(52%)에서 5%이상의 선량차이를 보여 contour로 치료계획을 할 경우 신중한 치료 선량의 선택이 필요함을 시사하였다. Simulation을 한 후 CT planning을 시행하여 치료 Field을 확인한 뒤, 치료 부위를 넓히거나 줄여서 보정한 경우가 18/87(21%)였고, 선량 loading의 변경이 있었던 환자는 15/87(17%)였다. 결론 : 본원의 CT planning은 부위별 정확한 밀도가 측정 입력되어 치료계획을 함으로써 tumon volume과 Critical orcal에 조사되는 정확한 선량을 알 수 있어서 Tumor control을 위한 총선량의 정확한 계산이 가능할뿐 아니라 field의 교정, loading의 변화등으로 적절한 선량 분포를 얻을 수 있어서 치료효과를 높일 수 있으며 주위 정상조직에 조사되는 방사선량을 정확히 측정함으로서 합병증을 최소화할 수 있어 therapeutic gain을 높이는데 밀도가 입력되는 CT planning에 크게 기여할것으로 기대된다. 또한 10%이상의 선량차이가 있을때 local control의 저하 가능성이 30%정도 될 수 있음을 감안할 때 폐암치료에서의 밀도가 입력된 CT planning은 필수적임을 알 수 있다.

• Imaging Science in Dentistry
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• 제37권3호
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• pp.127-131
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• 2007

Purpose: To measure the differences of the splint pin angulation and the position of the planned implant site after conventional tomographic analysis. Materials and Methods: The angulation and the location of the metal splint pin retained in acrylic stent were compared with the corrected angulation and the location of the implant fixture on the 331 tomographic images. Results: The stent pins were located buccal in 40%, lingual in 10% to the corrected implant site after analysis of the conventional tomographic image. The angle and the location of the maxillary splint pin were mainly directed buccal on incisor and canine regions. The angle and the location of the splint pins in premolar and molar regions needed less corrections in both maxilla and mandible. Conclusions: This study demonstrated that the use of tomographs was essential for successful dental implant planning.

• 전자공학회논문지B
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• 제28B권5호
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• pp.335-342
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• 1991

A real-tme nonlinear parameter tomography is pumping wave method. This tomorgraphy has a merit which requires no 180$^{\circ}$ projection datum, while the ray-bending effect is remrkably remained on the reconstructed image. In this paper we intend to compensate this ray-bending effect using the perturbation method. Impulsive pumping wave makes derived compensative term simple form, nad the compensative image is easily obtained. We perform computer simulation to confirm the improvement of corrected imate.

• 대한기계학회논문집
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• 제17권10호
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• pp.2563-2573
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• 1993

The measurements of monochromatic line-of-sight flame emission and light transmission in the same path having small spatial resolution were performed in an axisymmetric laminar propane $C_{3}H_{8}$ diffusion flame. The light wavelengthes of 632 nm, 800nm, 900nm were used. From these measurements, local point soot radiances (by Kirchhoff's law) and absorption coefficients were reconstructed by tomography. Thus local point soot temperatures and concentrations were obtained. The reconstructed soot temperatures and concentrations of local points have no differences between the case of visible range (632 nm) and the case of infrared range (800 nm and 900 nm). In these ranges, the scattering coefficient is much lower than the absorption coefficient. Soot mean temperature over the path also matches well with local soot temperature in outer region of the flame. Temperature measurement by thermocouple with different bead diameters $(222{\mu}m and 308{\mu}m)$ was carried in the same flame. Rapid insertion technique was used and radiation effect was considered. Radiation correction in the sooting region was carried out and the corrected result was in good agreement with the local soot temperature.

• Imaging Science in Dentistry
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• 제34권3호
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• pp.159-164
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• 2004

Purpose: To compare alveolar bony height of pantomograph with bony height of thin slice, multiplanar reformatted (MPR) Computed Tomograph. Materials and Methods : Panoramic radiograms of 12 young adult patients had been taken by one radologic technitian and the measurements were corrected by magnification ratio (1.20). The slice thickness of Multi-detector Computed Tomography (CT) was at least 1mm for the accuracy. The raw CT datas were imported into the V-works 4.0 (CyberMed Corp., Seoul, Korea) and transformed to MPR images. Pantomographic measurements of alveolar bone were compared to CT values by average mean bony height measurements for the accuracy. Inter-, and Intra-observer variability was evaluated. Results : There was no significant differences between height measurement of pantomography and that of CT (P>0.05). There were no significant differences in either inter-or intra-observer measurements (P>0.05). Conclusion : Pantomography showed relatively high accuracy and precision in measuring alveolar bony height.

• Journal of Chest Surgery
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• 제23권2호
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• pp.316-324
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• 1990

This study is a review of the early postoperative results in fifteen patients who diagnosed funnel chest and underwent the corrective surgical procedure by the sternal turnover[STO] or the sternocostal elevation[SCE] between January 1988 and February 1990. Thirteen among fifteen patients were male. Early eight patients were corrected by the STO and late seven patients by the SCE. Cosmetic result was excellent in one, fair in five, poor in two patients who received the STO and excellent in all patients corrected by the SCE. This unfavorable postoperative result in the STO group was due to the protrusion of inverted xiphisternal joint, the depression along the rejoined costal cartilages and forward tilting of the distal sternum. The lower vertebral indices measured on the lateral chest film were improved postoperatively from 0.42\ulcorner0.08 to 0.30\ulcorner0.05 in the STO group and from 0.31\ulcorner0.05 to 0.24\ulcorner0.03 in the SCE group. There was significant improvement in lower vertebral index in both groups, but it was difficult to compare the postoperative improvement between groups due to the different preoperative status. In the SCE group, the funnel index and the degree of depression measured on the computed tomography were significantly improved from 5.29\ulcorner1.72 and 3.11\ulcorner0.71 to 2.77\ulcorner0.46 and 1.63\ulcorner0.19[P<0.05], but there was no significant change in the degree of flatness postoperatively. This results suggest that sternocostal elevation is more cosmetic procedure than sternal turnover in children and in young adolescents whose funnel index measured on the computed tomography is low.