• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.99-107
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• 2024

Along with economic growth and industrial development, there is an increasing demand for various electronic components and device production of semiconductor, SMT component, and electrical battery products. However, these products may contain foreign substances coming from manufacturing process such as iron, aluminum, plastic and so on, which could lead to serious problems or malfunctioning of the product, and fire on the electric vehicle. To solve these problems, it is necessary to determine whether there are foreign materials inside the product, and may tests have been done by means of non-destructive testing methodology such as ultrasound ot X-ray. Nevertheless, there are technical challenges and limitation in acquiring X-ray images and determining the presence of foreign materials. In particular Small-sized or low-density foreign materials may not be visible even when X-ray equipment is used, and noise can also make it difficult to detect foreign objects. Moreover, in order to meet the manufacturing speed requirement, the x-ray acquisition time should be reduced, which can result in the very low signal- to-noise ratio(SNR) lowering the foreign material detection accuracy. Therefore, in this paper, we propose a five-step approach to overcome the limitations of low resolution, which make it challenging to detect foreign substances. Firstly, global contrast of X-ray images are increased through histogram stretching methodology. Second, to strengthen the high frequency signal and local contrast, we applied local contrast enhancement technique. Third, to improve the edge clearness, Unsharp masking is applied to enhance edges, making objects more visible. Forth, the super-resolution method of the Residual Dense Block (RDB) is used for noise reduction and image enhancement. Last, the Yolov5 algorithm is employed to train and detect foreign objects after learning. Using the proposed method in this study, experimental results show an improvement of more than 10% in performance metrics such as precision compared to low-density images.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.1
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• pp.1-9
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• 2009

Purpose: Lymphonodular hyperplasia of the colon (LNHC) is a rare finding in children and its significance as a pathologic finding is unclear. The aim of this study was to investigate the clinical significance of LNHC by analyzing clinical and histopathologic findings in children with LNHC. Methods: We analyzed data from 38 patients who were confirmed to have LNHC by colonoscopy. We checked age, birth history, past history, family history, and clinical symptoms. A hematologic exam, stool exam, and image studies were performed and biopsy specimens were examined by a pathologist. All patients were asked to have short- and long-term follow-up. Results: The mean age of the patients was 12.5${\pm}$14.4 months. All patients presented with complaints of bloody stool. They appeared healthy and the hematologic findings were within a normal range, with the exception of one case. There was no other identified source of bleeding. On histologic exam, 36 patients (94.7%) had lymphoid follicles and 34 patients (84.5%) fulfilled the criteria of allergic colitis. Regardless of diet modification and presence of residual symptom, there was no recurrence of bloody stool through long-term follow-up in all patients. Conclusion: LNHC is more common in infants who are affected by allergic colitis, but it can appear even after infancy. LNHC should be regarded as the etiology when there are any other causes of rectal bleeding, especially in healthy children. We suggest that LNHC has a benign course regardless of diet modification and it might not require excessive concerns.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.67-70
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• 2013

Purpose: Surge in patients with hepatocellular carcinoma, hepatic artery chemical embolization is one of the effective interventional procedures. The PET/CT examination plays an important role in determining the presence of residual cancer cells and metastasis, and prognosis after embolization. The other hand, the hepatic artery chemical embolization of embolic material used lipiodol produced artifacts in the PET/CT examination, and these artifacts results in quantitative evaluation influence. This study, the radioactivity density and the percentage error was evaluated by the extent of the impact of lipiodol in the image of PET/CT. Materials and Methods: 1994 NEMA Phantom was acquired for 2 minutes and 30 seconds per bed after the Teflon, water and lipiodol filled, and these three inserts into the enough to mix the rest behind radioactive injection with $20{\pm}10MBq$. Phantom reconfigure with the iterative reconstruction method the number of iterations for two times by law, a subset of 20 errors. We set up region of interest at each area of the Teflon, water, lipiodol, insert artifact occurs between regions, and background and it was calculated and compared by the radioactivity density(kBq/ml) and the% Difference. Results: Radioactivity density of the each region of interest area with the teflon, water, lipiodol, insert artifact occurs between regions, background activity was $0.09{\pm}0.04$, $0.40{\pm}0.17$, $1.55{\pm}0.75$, $2.5{\pm}1.09$, $2.65{\pm}1.16 kBq/ml$ (P <0.05) and it was statistically significant results. Percentage error of lipiodol in each area was 118%, compared to the water compared with the background activity 52%, compared with a teflon was 180% of the difference. Conclusion: We found that the error due to under the influence of the attenuation correction when PET/CT scans after lipiodol injection performed, and the radioactivity density is higher than compared to other implants, lower than background. Applying the nonattenuation correction images, and after hepatic artery chemical embolization who underwent PET/CT imaging so that the test should be take the consideration to the extent of the impact of lipiodol be.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.16-20
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• 2001

Purpose : To evaluate the effectiveness and tolerance of the postoperative radiation therapy for patients with Stage III thymoma and to define the optimal radiotherapeutic regimen Materials and Methods : We retrospectively analyzed the records of 24 patients with Stage III thymoma who were referred for postoperative radiation therapy in our institution from June, 1987 to May, 1999. Surgical therapy consisted of total resection in one patient, subtotal resection in seventeen, and biopsy alone in six patients. Age of the patients was ranged from 20 to 62 years with mean age of 47 years. Male to female ratio was 14 to 10. Radiation therapy was delivered with linear accelerator producing either 6 MeV or 10 MeV photons. The irradiated volume included anterior mediastinum and known residual disease. The supraclavicular fossae were not irradiated. The delivered total dose was ranged from 30 to 56 Gy. One patient received 30 Gy and eighteen patients received minimum of 50 Gy. Follow up period was ranged from 12 months to 8 years with median follow up of 40 months. Results : The overall local control rate for entire group of patients was $67\%$ at 5 years. The cumulative local failure rates at one, three and five year were $18\%,\;28\%\;and\;33\%$, respectively. In patients treated with subtotal resection and biopsy alone, local control rate was $76\%\;and\;33\%$, respectively. The actuarial observed survival rate at 5 years was $57\%$, and actuarial adjusted survival at 5 years was $72\%$. The difference between 5 year survival rates for patients treated with subtotal resection and biopsy alone was not statistically significant $(62\%\;vs\;30\%)$. Conclusion : We might conclude that postoperative radiation therapy was safe and effective treatment for patients with Stage III thymoma. Postoperative radiation therapy is recommended in cases where tumor margin is close or incomplete resection is accomplished.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.541-547
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• 1996

The previous monoclonal antibody labeling method for bone marrow immunoscintigrapy was complicated and laborious for clinical application. Also it showed a relatively low labeling efficiency. To improve this procedure, we compared several direct labeling methods of $^{99m}Tc$. 1) The labeling efficiency in the method using gluconate as a transchelator was low (40-70%), but immunoscintigraphy using this radiotracer produced a clear image. 2) To improve labeling efficiency, ${\beta}$-mercaptoethanol was removed after reduction. The labeling efficiency was improved up to 70-80%, but the radioactivity of the blood pool was high. 3) The higest labeling efficiency (>90%) and best quality images could be obtained by using MDP as a transchelating agent. It did not require additional procedures for separation of labeled antibodies. The immunoreactivity of this antibody was 60%. Residual MDP which can be taken up by the bone could be removed by PD-10 column. The reduced antibodies were stable with a high labeling efficiency (>90%) for up to 47 days by deep freezing. We concluded that the improved procedure for $^{99m}Tc$ labeling of anti-NCA-95 monoclonal antibody using MDP as a transchelating agent will be a simple and useful method for clinical application.

• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.25-30
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• 1998

Time-lapse crosswell seismic data, recorded before and after the cavity filling, showed that the filling increased the velocity at a known cavity zone in an old mine site in Inchon area. The seismic response depicted on the tomogram and in conjunction with the geologic data from drillings imply that the size of the cavity may be either small or filled by debris. In this study, I attempted to evaluate the filling effect by analyzing velocity measured from the time-lapse tomograms. The data acquired by a downhole airgun and 24-channel hydrophone system revealed that there exists measurable amounts of source statics. I presented a methodology to estimate the source statics. The procedure for this method is: 1) examine the source firing-time for each source, and remove the effect of irregular firing time, and 2) estimate the residual statics caused by inaccurate source positioning. This proposed multi-step inversion may reduce high frequency numerical noise and enhance the resolution at the zone of interest. The multi-step inversion with different starting models successfully shows the subtle velocity changes at the small cavity zone. The inversion procedure is: 1) conduct an inversion using regular sized cells, and generate an image of gross velocity structure by applying a 2-D median filter on the resulting tomogram, and 2) construct the starting velocity model by modifying the final velocity model from the first phase. The model was modified so that the zone of interest consists of small-sized grids. The final velocity model developed from the baseline survey was as a starting velocity model on the monitor inversion. Since we expected a velocity change only in the cavity zone, in the monitor inversion, we can significantly reduce the number of model parameters by fixing the model out-side the cavity zone equal to the baseline model.

• Korean Journal of Optics and Photonics
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• v.28 no.3
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• pp.108-115
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• 2017

We report the assembly procedure and performance evaluation of a visible and near-infrared spectrometer in the wavelength region of 400-900 nm, which is later to be combined with fore-optics (a telescope) to form a f/2.5 imaging spectrometer with a field of view of ${\pm}7.68^{\circ}$. The detector at the final image plane is a $640{\times}480$ charge-coupled device with a $24{\mu}m$ pixel size. The spectrometer is in an Offner relay configuration consisting of two concentric, spherical mirrors, the secondary of which is replaced by a convex grating mirror. A double-pass test method with an interferometer is often applied in the assembly process of precision optics, but was excluded from our study due to a large residual wavefront error (WFE) in optical design of 210 nm ($0.35{\lambda}$ at 600 nm) root-mean-square (RMS). This results in a single-path test method with a Shack-Hartmann sensor. The final assembly was tested to have a RMS WFE increase of less than 90 nm over the entire field of view, a keystone of 0.08 pixels, a smile of 1.13 pixels and a spectral resolution of 4.32 nm. During the procedure, we confirmed the validity of using a Shack-Hartmann wavefront sensor to monitor alignment in the assembly of an Offner-like spectrometer.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.87-94
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• 2001

Purpose : To evaluate the role of LINAC-based stereotactic radiosurgery (SRS) in the management of meningiomas, we reviewed clinical response, image response, neurological deficits for patients treated at our institution. Methods and materials : Between February 1995 and December 1999, twenty-six patients were treated with SRS. Seven patients had undergone prior resection. Nineteen patients received SRS as the initial treatment. There were 7 male and 19 female patients. The median age was 51 years (range, $14\~67\;years$). At least one clinical symptom presented at the time of SRS in 17 patients and cranial neuropathy was seen in 7 patients. The median tumor volume was $4.7\;cm^3\;(range,\;0.7\~16.5\;m^3)$. The mean marginal dose was 15 Gy (range, $10\~20\;Gy$), delivered to the $80\%$ isodose surface (range, $46\~90\%$). The median clinical and imaging follow-up periods were 27 months (range, 1-71 months) and 25 months (range, $1\~52\;months$), respectively. Results : Of 14 patients who had clinical follow-up of one year or longer, thirteen patients $(93\%)$ were improved clinically at follow-up examination. Clinical symptom worsened in one patient at 4 months after SRS as a result of intratumoral edema, who underwent surgical resection at 7 months. OF 14 patients who had radiologic follow-up of one year or longer, tumor volume decreased in 7 patients $(50\%)$ at a median of 11 months (range, $6\~25\;months$), remained stable in 6 patients $(43\%)$, and increased in one patient $(7\%)$, who underwent surgical resection at 44 months. New radiation-induced neurological deficits developed in six patients $(23\%)$. Five patients $(19\%)$ had transient neurological deficits, completely resolved by conservative treatment including steroid therapy. Radiation-induced brain necrosis developed in one patient $(3.8\%)$ at 9 months after SRS who followed by surgical resection of tumor and necrotic tissue. Conclusions : LINAC-based SRS proves to be an effective and safe management strategy for small to moderate sized meningiomas, inoperable, residual, and recurrent, but long-term follow-up will be necessary to fully evaluate its efficacy. To reduce the radiation-induced neurological deficit for large size meningioma and/or in the proximity of critical and neural structure, more delicate treatment planning and optimal decision of radiation dose will be necessary.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.481-488
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• 2005

Purpose: Functional imaging of dopamine transporter (DAT) defines integrity of the dopaminergic system, and DAT is the target site of drugs of abuse such as cocaine and methamphetamine. Functional imaging the DAT may be a sensitive and selective indicator of neurotoxic change by the drug. The aim of the present study is to evaluate the clinical implications of qualitative/quantitative analyses of dopamine transporter imaging in methamphetamine abusers. Materials and Methods: Six detoxified methamphetamine abusers (abuser group) and 4 volunteers (control group) were enrolled in this study. Brain MRI was performed in all of abuser group. Abuser group underwent psychiatric and depression assessment using brief psychiatric rating scale (BPRS) and Hamilton depression rating scale (HAMD), respectively. All of the subjects underwent I-123 IPT SPECT (IPT SPECT). IPT SPECT image was analysed with visual qualitative method and quantitative method using basal ganglia dopamine transporter (DAT) specific/non-specific binding ratio (SBR). Comparison of DAT SBR between abuser and control groups was performed. We also performed correlation tests between psychiatric and depression assessment results and DAT SBR in abuser group. Results: All of abuser group showed normal MRI finding, but had residual psychiatric and depressive symptoms, and psychiatric and depressive symptom scores were exactly correlated (r=1.0, p=0.005) each other. Five of them showed abnormal finding on qualitative visual I-123 IPT SPECT Abuser group had lower basal ganglia DAT SBR than that of control ($2.38{\pm}0.20\;vs\;3.04{\pm}0.27$, p=0.000). Psychiatric and depressive symptoms were negatively well correlated with basal ganglia DAT SBR (r=-0.908, p=0.012, r=-0.924, p=0.009). Conclusion: These results suggest that dopamine transporter imaging using I-123 IPT SPECT may be used to evaluate dopaminergic system of the basal ganglia and the clinical status in methamphetamine abusers.