• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.583-589
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• 2011

The dielectric breakdown of bone-like materials subject to purely electric fields is investigated. In general, these materials consist of some layers with stronger dielectric strength and others with weaker dielectric strength in a parallel staggered pattern. The growth of the conductive channel is impeded during penetration of the weaker layer in the bone-like material because the electric-field concentration is relieved. The electric-field distribution around the head of the tubular channel is obtained from finite element analysis. The dielectric strength of the bone-like material is evaluated using the J integral, and some parameters affecting the dielectric strength are determined. It is shown that the J-integral values are reduced with an increase in the breakdown area in the weaker layer. It is also found that the ratio of the permittivity of the weaker layer to that of the stronger layer can strongly affect the dielectric breakdown.

• The Korean Journal of Nuclear Medicine
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• v.28 no.2
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• pp.206-213
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• 1994

We studied 90 patients(179 femoral heads) with avascular necrosis of femoral head, who had been performed X-ray, bone scan and MRI to compare of the findings of AVN on bone scan between each other, retrospectively. The patients were 82 males and 9 females, their mean age was 45 years. Radiographic stages were classified by Steinberg modification, radionuclide stages were classified as followed; stage o(or type 0) : normal, stage 1 : faint ring like uptake around the femoral head, stage 2: intense ring like uptake, stage 3: irregular increased uptake with central photon defect, stage 4 : Intense diffuse increased uptake at femoral head and stage 5 : hip joint deformity with relatively mild increased uptake. The findings of MRI were classified according to extent, location, early or advanced lesion, signal intensity of the lesion and joint effusion. 156(87%) of 179 femoral heads had avascular necrosis, 68(75.5%) of 90 patients had bilateral AVN, 35 femoral heads had early stage and 120 had advanced stage. The detection rate of AVN by X-ray and bone scan were 85% (134), 91.6% (143), respectively. Early AVN with atypical types of bone scan showed larger extent, moderate to large amount of joint effusion, soft tissue hypertrophy within joint, and secondary degenerative changes. Bone scan had relatively high detection rate in the diagnosis of AVN of femoral head, and demonstrated various types depending on the disease stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1467-1468
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• 2011

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.243-252
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• 2018

In this paper, we propose a bone region extraction method using a snake algorithm and a particle filter in CT image. We extract the bone outline using the snake algorithm, and extract the bone area by moving the particle filter along this outline. If other bones are in close proximity to the bone outline, the snake algorithm may not be able to extract the bone outline completely. At this time, the particle filter extracts the bone area while compensating for the error. In this paper, we compared the proposed method with the conventional morphological processing method. The result is similar when other bones are not close to the bone area to be extracted. However, if other bones are close to each other, The accuracy of the proposed method is higher than the conventional morphological processing method.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.342-352
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• 2014

This paper proposes an automatic segmentation method of cortical bone and trabecular bone and describes an implementation of structural analysis method of trabecular bone in micro-CT images. The proposed segmentation method extract bone region with binarization using a threshold value. Next, it finds adjacent contour lines from outer boundary line into inward direction and sets candidate regions of cortical bone. Next it remove cortical bone region by finding the candidate cortical region of which the average pixel value is maximum. We implemented the method which computes four structural indicators BV/TV, Tb.Th, Tb.Sp, Tb.N by using VTK(Visualization ToolKit) and sphere fitting algorithm. We applied the implemented method to twenty proximal femur of mouses and compared with the manual segmentation method. Experimental result shows that the average error rates between the proposed segmentation method and the manual segmentation method are less than 3% for the four structural indicatiors. This result means that the proposed method can be used instead of the combersome and time consuming manual segmentation method.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.373-384
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• 2000

The goal of this paper is to develop a computational method to predict cancellous bone density distributions based upon continuum levels of volumetric strain. Volumetric strain is defined as the summation of normal strains, excluding shear strains, within an elastic range of loadings. Volumetric strain at a particular location in a cancellous structure changes with changes of the boundary conditions (prescribed displacements, tractions, and pressure). This change in the volumetric strain is postulated to predict the adaptive change in the bone apparent density. This bone remodeling theory based on volumetric strain is then used with the finite element method to compute the apparent density distribution for cancellous bone in both lumbar spine and proximal femur using an iterative algorithm, considering the dead zone of strain stimuli. The apparent density distribution of cancellous bone predicted by this method has the same pattern as experimental data reported in the literature (Wolff 1892, Keller et al. 1989, Cody et al. 1992). The resulting bone apparent density distributions predict Young's modulus and strength distributions throughout cancellous bone in agreement with the literature (Keller et al. 1989, Carter and Hayes 1977). The method was convergent and sensitive to changes in boundary conditions. Therefore, the computational algorithm of the present study appears to be a useful approach to predict the apparent density distribution of cancellous bone (i.e. a numerical approximation for Wolff's Law)

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.63-69
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• 2006

Purpose : Marrow edema and fatty degeneration of the hip joint bones could be initial and late signs in hip joint and its bone diseases respectively, which might be differentiated from age-related marrow conversion pattern. So authors have investigated normal marrow conversion pattern of the femur and acetabulum around the hip joints. Materials and methods : Three coronal MR images of 288 hip joint bones in 144 subjects, aged 2 days to 76 years divided to 8 groups every 10 years, were retrospectively analysed for the location and appearance of the converted yellow marrow. The converted yellow marrow were divided to head, neck, and trochanter in the proximal femur and below and above 50% in acetabulum of the hip. Results : The most common type of marrow conversion is the converted yellow marrow in the entire proximal femur and below 50% of acetabulum of the hip. We observed the start of marrow conversion in just before and after 2 years old and stopped at just before and after 20 years old. Conclusion : The understanding of age-related marrow conversion pattern of the hip joint bones would provide some information for differentiation from pathologic condition of them such as edema, fatty degeneration, metastasis, or leukemia.

• Progress in Medical Physics
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• v.6 no.2
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• pp.111-125
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• 1995

The stress distribution of bone is altered by the rigid bone plate, sometimes resulting in unfavorable osteoporosis. The rigidity and the biocompatibility are important factors for the design of prosthesis, however, it is also necessary to consider the effect on the bone remodeling. In this paper, it is attempted to establish an approximate and simple method to predict the trend of the configuration of surface bone remodeling upon a bone plate using stress analysis. Thus, three dimensional finite element model of plated-human femur is generated and simulated. In addition, the stress difference method (SDM) is introduced and attempted to demonstrate the configuration of surface bone remodeling of the plated-human femur.

• Culinary science and hospitality research
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• v.19 no.4
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• pp.231-242
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• 2013

This study was performed to develop cod bone stock using various nutritional elements in cod bone with the addition of various amounts of tomatoes (2%, 4%, 6% and 8%). Moisture contents, pH, L value and Na contents decreased, while the salinity, sugar contents, a value, b value and Mg, K, Ca, Fe contents increased with increased rates of tomatoes. Fourteen types of free amino acid were detected, and stock containing 6% of tomato addition had the highest free amino acid content. In the test on different attributes, tomato content significantly affected the properties of the stock including color intensity, savory flavor, tomato flavor, tomato taste, savory taste and after taste. In the acceptance test, 6% of tomato addition was preferred for appearance, flavor, taste, texture and overall quality. Consequently, the optimal tomato content for maximizing the overall quality of cod bone stock was 6%.

• Journal of KIISE:Software and Applications
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• v.36 no.12
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• pp.967-976
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• 2009

In this paper, we propose an automatic lower extremity vessel extraction based on rigid registration and bone elimination techniques in CT and CT angiography images. First, automatic partitioning of the lower extremity based on the anatomy is proposed to consider the local movement of the bone. Second, rigid registration based on distance map is performed to estimate the movement of the bone between CT and CT angiography images. Third, bone elimination and vessel masking techniques are proposed to remove bones in CT angiography image and to prevent the vessel near to bone from eroding. Fourth, post-processing based on vessel tracking is proposed to reduce the effect of misalignment and noises like a cartilage. For the evaluation of our method, we performed the visual inspection, accuracy measures and processing time. For visual inspection, the results of applying general subtraction, registered subtraction and proposed method are compared using volume rendering and maximum intensity projection. For accuracy evaluation, intensity distributions of CT angiography image, subtraction based method and proposed method are analyzed. Experimental result shows that bones are accurately eliminated and vessels are robustly extracted without the loss of other structure. The total processing time of thirteen patient datasets was 40 seconds on average.