• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.991-1000
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• 2021

Among non-invasive blood glucose detection technologies, the optical technique is a method that uses light reflection, absorption, and scattering characteristics when passing through a biological medium. It reduces pain or discomfort in measurement and has no risk of infection. So it is becoming a major flow of blood glucose detection research. Among them, near-infrared spectroscopy has a disadvantage in that the complexity increases when analyzing signals detected due to interferences between proteins and acids that share a similar absorption function with blood glucose molecules. In this study, a non-invasive sensor system with multiple near-infrared bands was designed and manufactured to alleviate the deterioration of blood glucose detection function that may occur due to skin absorption of near-infrared rays. A blood survey was conducted to verify the system, and the degree of blood glucose response in the blood was collected as spectral data, and the results of this study were quantitatively verified in terms of correlation between the data and blood glucose.

• Radiation Oncology Journal
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• v.13 no.1
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• pp.95-100
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• 1995

Purpose : To evaluate the effect on surface dose due to Aquaplast used for immobilizing the patients with head and neck cancers in photon beam radiotherapy Materials and Methods: To assess surface and buildup region dose for 6MV X-ray from linear accelerator(Siemens Mevatron 6740), we measured percent ionization value with the Markus chamber model 30-329 manufactured by PTW Frieburg and Capintec electrometer, model WK92. For measurement of surface ionization value, the chamber was embedded in $25{\times}25{\times}3cm^3$ acrylic phantom and set on $25{\times}25{\times}5cm^3$ polystyrene phantom to allow adequate scattering. The measurements of percent depth ionization were made by placing the polystyrene layers of appropriate thickness over the chamber. The measurements were taken at 100cm SSD for $5{\times}5cm^2$, $10{\times}10cm^2$ and $15{\times}15cm^2$ field sizes, respectively. Placing the layer of Aquaplast over the chamber, the same procedures were repeated. We evaluated two types of Aquaplast: 1.6mm layer of original Aquaplast(manufactured by WFR Aquaplast Corp.) and transformed Aquaplast similar to moulded one for immobilizing the patients practically. We also measured surface ionization values with blocking tray in presence or absence of transformed Aquaplast. In calculating percent depth dose, we used the formula suggested by Gerbi and Khan to correct overresponse of the Markus chamber. Results : The surface doses for open fields of $5{\times}5cm^2$, $10{\times}10cm^2$, and $15{\times}15cm^2$ were $79\%$, $13.6\%$, and $18.7\%$, respectively. The original Aquaplast increased the surface doses upto $38.4\%$, $43.6\%$, and $47.4\%$, respectively. For transformed Aquaplast, they were $31.2\%$, $36.1\%$, and $40.5\%$, respectively. There were little differences in percent depth dose values beyond the depth of Dmax. Increasing field size, the blocking tray caused increase of the surface dose by $0.2\%$, $1.7\%$, $3.0\%$ without Aquaplast, $0.2\%$, $1.9\%$, $3.7\%$ with transformed Aquaplast, respectively. Conclusion: The original and transformed Aquaplast increased the surface dose moderately. The percent depth doses beyond Dmax, however, were not affected by Aquaplast. In conclusion, although the use of Aquaplast in practice may cause some increase of skin and buildup region dose, reductioin of skin-sparing effect will not be so significant clinically.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.423-430
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• 2013

Recently, the personal identification technologies using vein pattern of back of the hand, palm, and finger have been developed actively because it has the advantage that the vein blood vessel in the body is impossible to damage, make a replication and forge. However, it is difficult to extract clearly the vein region from captured vein images through common image prcessing based region segmentation method, because of the light scattering and non-uniform internal tissue by skin layer and inside layer skeleton, etc. Especially, it takes a long time for processing time and makes a discontinuity of blood vessel just in a image because it has non-uniform illumination due to use a locally different adaptive threshold for the binarization of acquired finger-vein image. To solve this problem, we propose illumination normalization based fast method for extracting the finger-vein region. The proposed method has advantages compared to the previous methods as follows. Firstly, for remove a non-uniform illumination of the captured vein image, we obtain a illumination component of the captured vein image by using a low-pass filter. Secondly, by extracting the finger-vein path using one time binarization of a single threshold selection, we were able to reduce the processing time. Through experimental results, we confirmed that the accuracy of extracting the finger-vein region was increased and the processing time was shortened than prior methods.

• Progress in Medical Physics
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• v.6 no.2
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• pp.51-60
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• 1995

Lithium Fluoride (LiF; TLD-100) crystal chips are normally used as thermolu minescence dosimeters (abbreviated as NC-100) for estimating the absorbed dose to the skin of a patient or in a solid water phantom undergoing radiotherapy with megavoltage photon (6 and 15MV) beams. In general, investigation has revealed a reduction in the sensitivity of NC-100 chips after many runs through heating cycles. A TLD-100 chip laminated with gold plate (140${\mu}{\textrm}{m}$) on the upper surface layer of its face toward the photon beam (abbreviated as GC-100) has properties different from that of a NC-100 chip activated by incident photons and contaminant electrons with various lower energies coming from the gantry head and air. Activation of the valence band electrons of GC-100 chips by incident photons, positrons and electrons-which come from the gold plate by mainly pair production process and partly from Compton scattering-results in more enhanced signal intensity, higher response per monitor unit, as well as a good linearity with monitor units and independence of dose rate. Since the electron beams (6 and 15 MeV) do not have the probability of pair production process with gold plate, there is only a small difference (about a 3.3％ increase for 15 MeV) in the signal gaps in the TL readout for electron beams between GC- and NC-100 chips. The 3.3％ increase is entirely due to the buildup caused by the 140 m gold plate. The sensitivity of GC-100 chips is much more susceptible to high energy photon beams than electron one because of pair production. The interaction of high energy photon with a material of high atomic number, such as the good plate in this case, results in a considerably significant probability of pair production. The gold plate on the NC-100 chips acts as not only an intensifier of their signals but also acts as a filter of contaminant electrons in therapeutic high energy X-ray beams.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.121-131
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• 2014

Due to the high UV light scattering effect of Zinc oxide (ZnO), it is frequently used in sunscreen skincare products. Recently ZnO coated with silica has been used in cosmetics to improve UV protection, texture, decreased photocatalytic activity, dispersibility and stability of the skin care product. In this study, we developed a ZnO composite powder coated with silica for the future application to skincare products to block UV rays that could cause photoaging. To improve consumer's satisfaction rating, we used ZnO microparticles which are widely used in the cosmetics industry. The silica was coated using hydrothermal method with sodium silicate and acid hydrolysis. UV protection of the composite powder was analyzed by UV-Vis and in-vitro test and the advantages for practical use of this powder as a skincare product were determined.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.757-763
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• 2019

Recently, Following the recent development of flat panel detector with wide dynamic ranges, increasing numbers of healthcare providers have begun to use digital radiography. As a result, filter thickness standards should be reestablished, as current clinical practice requires the use of thicknesses recommended by the National Council on Radiation Protection and Measurements, which are based on information, acquired using conventional analog systems. Here we investigated the possibility of minimizing dose creep and optimizing patient dose using Al filters in digital radiography. The use of thicker Al filters resulted in a maximum 19.3% reduction in the entrance skin exposure dose when medical images with similar sharpness values were compared. However, resolution, which is a critical factor in imaging, had a significant change of 1.01 lp/mm. This change in resolution is thought to be due to the increased amount of scattered rays generated from the object due to the X-ray beam hardening effect. The increase in the number of scattered rays was verified using the scattering degradation factor. However, the FPD, which has recently been developed and is widely used in various areas, has greater response to radiation than analog devices and has a wide dynamic range. Therefore, the FPD is expected to maintain an appropriate level of resolution corresponding to the increase in the scattered-ray content ratio, which depends on filter thickness. Use of the FPD is also expected to minimize dose creep by reducing the exposure dose.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.424-430
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• 2010

Immuno-modulatory activities of peptides from Asterias amurensis were investigated using a nano-encapsulation process. The molecular weights of the peptides in the range of 5-7 kDa were separated using Sephadex G-75 gel filtration. Eighty-five percent of the nano-particles were in the 300 nm range using dynamic light scattering. The cytotoxicity of the A. amurensis nano-particles against CCD-986sk human dermal fibroblast cells was 11.64% after adding 1.0 mg/mL of the samples, which was lower than that from the control (13.28% collagen). The secretion of $NO^-$ from macrophages was estimated as $40\;{\mu}M$ after adding 1.0 mg/mL of gelatin nano-particles, which was higher than the others. Prostaglandin $E_2$ production from UV-induced human skin cells decreased greatly to 860 pg/mL after adding 1.0 mg/mL of the samples. Confocal microscopy revealed that nano-particles effectively penetrated the cells within 1 hour. From these results, we consider that nano-encapsulation of the peptides from A. amurensis can improve their biological functions.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.77-81
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• 2014

Purpose : In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. Materials and Methods : In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made ??up to 5mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. Results : When there was the Optimold mask in the eyeball part, it was measured at $10.2cGy{\pm}1.5$ in the simulation therapy, and at $24.8cGy{\pm}2.7$ in the treatment, and when the Optimold mask was removed in the eye part, it was measured at $12.9cGy{\pm}2.2$ in the simulation therapy, and at $17.6cGy{\pm}1.5$ in the treatment. Conclusion : In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3 cGy in the simulation therapy and was reduced approximately 7 cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause cataracts and side effects was considered to be reduced due to decrease of the absorbed dose to the eye lens which had the high sensitivity on the radiation.