• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.6
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• pp.545-554
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• 2000

Compton X-ray backscatter technique has been used to quantitatively assess the impact damage in quasi-isotropic laminated composites and to obtain a cross-sectional profile of impact-damaged laminated composites from the density variation of the cross section. An adaptive filter is applied to the Compton backscattering data for the reconstruction and noise reduction from many sources including quantum noise, especially when the SNR(signal-to-noise ratio) of the image is relatively low. A nonlinear reconstruction model is also proposed to overcome distortion of the Compton backscatter image due to attenuation effects, beam hardening, and irregular distributions of the fibers and the matrix in composites. Delaminations masked or distorted by the first few delaminations near the front surface are detected and characterized both in width and location, by application of an error minimization algorithm.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.33-43
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• 2021

Background Acellular dermal matrices (ADMs) have become an essential material for implant-based breast reconstruction. No previous studies have evaluated the effects of sterility of ADM under conditions of radiation. This study compared sterile (irradiated) and aseptic (non-irradiated) ADMs to determine which would better endure radiotherapy. Methods Eighteen male Balb/C mice were assigned to the control group with no irradiation (group 1) or one of two other groups with a radiation intensity of 10 Gy (group 2) or 20 Gy (group 3). Both sterile and aseptic ADMs were inserted into the back of each mouse. The residual volume of the ADM (measured using three-dimensional photography), cell incorporation, α-smooth muscle actin expression, and connective tissue growth factor expression were evaluated. The thickness and CD3 expression of the skin were measured 4 and 8 weeks after radiation. Results In groups 2 and 3, irradiated ADMs had a significantly larger residual volume than the non-irradiated ADMs after 8 weeks (P<0.05). No significant differences were found in cell incorporation and the amount of fibrosis between irradiated and non-irradiated ADMs. The skin was significantly thicker in the non-irradiated ADMs than in the irradiated ADMs in group 3 (P<0.05). CD3 staining showed significantly fewer inflammatory cells in the skin of irradiated ADMs than in non-irradiated ADMs in all three groups after 4 and 8 weeks (P<0.05). Conclusions Under radiation exposure, irradiated ADMs were more durable, with less volume decrease and less deposition of collagen fibers and inflammatory reactions in the skin than in non-irradiated ADMs.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.323-330
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• 2014

Image reconstruction is one of the most important processes in CT (Computed tomography) technology. For fast scanning and low dose to the objects, iterative reconstruction is becoming more and more important. In the implementation of iterative reconstruction, projection and backprojection processes are considered to be indispensable parts. However, many approaches for projection and backprojection may result severe image artifacts due to their discrete characteristics and affects the reconstructed image quality. Thus, new approaches for projection and backprojection are highly demanded these days. In this paper, distance-driven approach was evaluated and compared with other conventional methods. The numerical simulator was developed to make the phantoms, and projection and backprojection images were compared using these approaches. As a result, it turned out that there are less artifacts during projection and backprojection in parallel and fan beam geometry.

• Archives of Plastic Surgery
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• v.44 no.6
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• pp.516-522
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• 2017

Background Implant-based breast reconstruction is being performed more frequently, and implants are associated with an increased risk of infection. We reviewed the clinical features of cases of implant infection and investigated the risk factors for breast device salvage failure. Methods We retrospectively analyzed 771 patients who underwent implant-based breast reconstruction between January 2010 and December 2016. Age, body mass index, chemotherapy history, radiation exposure, and smoking history were assessed as potential risk factors for postoperative infection. We also evaluated the presence and onset of infection symptoms, wound culture pathogens, and other complications, including seroma, hematoma, and mastectomy skin necrosis. Additionally, we examined the mastectomy type, the use of acellular dermal matrix, the presence of an underlying disease such as hypertension or diabetes, and axillary node dissection. Results The total infection rate was 4.99% (58 of 1,163 cases) and the total salvage rate was 58.6% (34 of 58). The postoperative duration to closed suction drain removal was significantly different between the cellulitis and implant removal groups. Staphylococcus aureus infection was most frequently found, with methicillin resistance in 37.5% of the cases of explantation. Explantation after infection was performed more often in patients who had undergone 2-stage expander/implant reconstruction than in those who had undergone direct-to-implant reconstruction. Conclusions Preventing infection is essential in implant-based breast reconstruction. The high salvage rate argues against early implant removal. However, when infection is due to methicillin-resistant S. aureus and the patient's clinical symptoms do not improve, surgeons should consider implant removal.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.91-98
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• 2017

Electrical impedance tomography is a nondestructive imaging technique to reconstruct unknown conductivity distribution based on applied current data and measured voltage data through an array of electrodes attached on the periphery of a domain. In this paper, an inverse method based on truncated singular value decomposition is proposed to solve the inverse problem with the generalized Tikhonov regularization and to reconstruct the conductivity distribution. In order to reduce the inverse computational time, truncated singular value decomposition is applied to the inverse term after the generalized regularization matrix is taken out from the inverse matrix term. Numerical experiments and phantom experiments have been performed to verify the performance of the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1080-1087
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• 2009

This paper presents an algorithm to acquire 3D geometric information using a virtual plane method. The method to measure 3D information on the plane is easy, because it's not concerning value on the z-axis. A plane can be made by arbitrary three points in the 3D space, so the algorithm is able to make a number of virtual planes from feature points on the target object. In this case, these geometric relations between the origin of each virtual plane and the origin of the target object coordinates should be expressed as known homogeneous matrices. To include this idea, the algorithm could induce simple matrix formula which is only concerning unknown geometric relation between the origin of target object and the origin of camera coordinates. Therefore, it's more fast and simple than other methods. For achieving the proposed method, a regular pin-hole camera model and a perspective projection matrix which is defined by a geometric relation between each coordinate system is used. In the final part of this paper, we demonstrate the techniques for a variety of applications, including measurements in industrial parts and known patches images.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.189-193
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• 2005

Reconstruction of calvarial bone defects from congenital anomaly or from bone loss due to traumatic or neoplastic processes remains a significant problem in craniofacial surgery and neurosurgery. To facilitate bone regeneration, there have been many trials such as autologous bone graft or allograft, and the addition of demineralized bone matrix and matrix-derived growth factor. Guided bone regeneration is one of the methods to accelerate bone healing for calvarial bone defects especially in children. Pericranium is one of the most usable structure in bone regeneration. It protects the dura and sinus, and provides mechanical connection between bone fragments. It supplies blood to bone cortex and osteoprogenitor cells and enhances bone regeneration. For maximal effect of pericranium in bone regeneration, authors used pericranium as a flap for covering calvarial defects in surgeries of 11 craniosynostosis patients and achieved satisfactory results: The bone regeneration of original cranial defect in one year after operation was 74.6%(${\pm}8.5%$). This pericranial flap would be made more effectively by individual dissection after subgaleal dissection rather than subperiosteal dissection. In this article, we reviewed the role of pericranium and reported its usefulness as a flap in surgery of craniosynostosis to maximize bone regeneration.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.1
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• pp.55-59
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• 2013

In the oral and maxillofacial area, bone defects are created by various reasons and demand for bone grafts, while dental implant implantation has been increased consistently. To solve these problems, there has been development of autogenous tooth-bone graft material (AutoBT$^{(R)}$, Korea Tooth Bank Co., Korea), and we have collected ground reasons to substitute free autobone graft with this material in clinical use. This autogenous tooth-bone graft material is produced in powder type and block type. Block type is useful in esthetic reconstruction of the defect site and vertical and horizontal augmentation of alveolar bone because this type has high strength value, well maintained shape and is less absorbed. Therefore, the author of this study gained favorable result by grafting the block type autogenous tooth-bone graft material after dental implant implantation on the bone defects of the mandibular molar extraction site. Moreover, the author represents this case with literature review after confirming bone remodeling on the computed tomography image and by histological analysis.

• Archives of Craniofacial Surgery
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• v.18 no.2
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• pp.132-136
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• 2017

Frey's syndrome and infra-auricular depressed deformities are the ones of the most common complications that can occur after total parotidectomy. We report 1 case of pleomorphic adenoma occurred in the deep lobe that obtained good results from using acellular dermal matrix (ADM) after total parotidectomy. A 24-year-old man visited the hospital with oval shape mass in right mandibular angle which of 4 cm in size was found in the deep lobe of right parotid gland from Magnetic resonance imaging scanning and a pleomorphic adenoma was suspected. A total parotidectomy was performed while preserving the facial nerve. The material known as ADM were placed in the depressed part from where the mass was removed, and the site was sutured. The surgery site was healed well without any complications such as Frey's syndrome or infra-auricular depressed deformities. The pathological result was confirmed as pleomorphic adenoma. In addition to these advantages, it does not have little potential of deformation by the gravity after the surgery, and there is no restraint on circulation, which makes fabrication free and each deformation into various shapes can be described as another advantage of the reconstruction using the ADM.

• Archives of Craniofacial Surgery
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• v.25 no.5
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• pp.252-256
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• 2024

This paper presents a novel approach to the correction of zygomatic malposition and secondary reconstruction orbital floor fractures, highlighting the use of hydrated acellular dermal matrix (ADM), specifically CGDerm One-Step, in a case where traditional solid implants failed to maintain structural integrity and volume. A 27-year-old woman with persistent facial deformities following a traumatic incident underwent a transformative procedure that utilized ADM for volume correction and structural support, addressing significant challenges such as enophthalmos and facial contour depression. This approach was necessitated by the descent of the entire orbital floor and a previously placed implant (Medpor), leading to unsatisfactory volume correction. By integrating ADM with titanium-reinforced fan plates (Synpor), the surgery successfully restored the patient's facial symmetry and addressed her functional concerns, including diplopia and limited eye movement. Postoperative evaluations demonstrated the long-term effectiveness of this method, with significant improvements in facial contour and eye symmetry. Our findings suggest that ADM, particularly in its hydrated form, offers a reliable alternative to traditional bone grafts and implants for correcting complex craniofacial deformities, providing both aesthetic and functional benefits. This case underscores the importance of adaptable, tissue-mimicking materials in facial reconstructive surgery, offering insights into their potential for broader application in post-traumatic facial corrections.