• Journal of Radiation Protection and Research
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• v.31 no.3
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• pp.129-134
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• 2006

A TL pellet for a neutron dose measurement (KCT-306) by embedding a $^6Li$-compound into a $CaSO_4:Dy$ phohphor was developed based upon the technical information of KCT-300. The KCT-300 is an another kind of $CaSO_4:Dy$ TL detector shich was developed at KAERI, in which small amounts of $NH_4H_2PO_4$ have been emvedded as a binding material. This paper presented the optimized manufacturing condition of KCT-306 and compared its sensitivity with that of the commercialized neutron TL pellets. $CaSO_4:Dy$ Phosphor with grain size ranging less than $45{\mu}m$ are used for the KCT-306. The optimum $CaSO_4:Dy$ TL phosphor, $^6Li$-compounds and P-compound as the binding material are determined as 20-40wt%, 50-70wt% and 20wt%. The TL pellet combination of our KCT-306/KCT-300, TLD-600/TLD-700 and TLD-600H/TLD-700H(Harshaw) have been irradiated in the neutron/gamma mixed fields from a $D_2O$ moderated $^{252}Cf$ neutron source. The KCT-300, TLD-700 and TLD-700H were used at the same time as gamma ray discriminators in the neutron/gamma mixed fields. It was found that the neutron/gamma response ratios of KCT-306/KCT-300, which were developed in this study, were approximately 4 times higher than those of the commercial TLD-600H/TLD-700H.

• Tuberculosis and Respiratory Diseases
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• v.69 no.2
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• pp.81-94
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• 2010

Background: Autophagy is an important adaptive mechanism in normal development and in response to changing environmental stimuli in cancer. Previous papers have reported that different types of cancer underwent autophagy to obtain amino acids as energy source of dying cells in nutrient-deprived conditions. However, whether or not autophagy in the process of lung cancer causes death or survival is controversial. Therefore in this study, we investigated whether nutrient deprivation induces autophagy in human H460 lung cancer cells. Methods: H460, lung cancer cells were incubated in RPMI 1640 medium, and the starved media, which are BME and RPMI media without serum, including 2-deoxyl-D-glucose according to time dependence. To evaluate the viability and find out the mechanism of cell death under nutrient-deprived conditions, the MTT assay and flow cytometry were done and analyzed the apoptotic and autophagic related proteins. It is also measured the development of acidic vascular organelles by acridine orange. Results: The nutrient-deprived cancer cell is relatively sensitive to cell death rather than normal nutrition. Massive cytoplasmic vacuolization was seen under nutrient-deprived conditions. Autophagic vacuoles were visible at approximately 12 h and as time ran out, vacuoles became larger and denser with the increasing number of vacuoles. In addition, the proportion of acridine orange stain-positive cells increased according to time dependence. Localization of GFP-LC3 in cytoplasm and expression of LC-3II and Beclin 1 were increased according to time dependence on nutrient-deprived cells. Conclusion: Nutrient deprivation induces cell death through autophagy in H460 lung cancer cells.

• Radiation Oncology Journal
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• v.36 no.3
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• pp.200-209
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• 2018

Purpose: To evaluate the effectiveness and feasibility of chemoradiotherapy (CRT) using simultaneous integrated boost-intensity modulated radiotherapy (SIB-IMRT) in locally advanced pancreatic cancer (LAPC) patients. Materials and Methods: Between January 2011 and May 2015, 47 LAPC patients received CRT using SIB-IMRT. Prior to SIB-IMRT, 37 patients (78.7%) received induction chemotherapy (IC-CRT group) and remaining 10 patients (21.3%) did not received induction chemotherapy (CRT group). During SIB-IMRT, all patients received concomitant chemotherapy, with gemcitabine (n = 37) and capecitabine (n = 10). Results: At the time of analysis, 45 patients had died and 2 patients remained alive and the median follow-up time was 14.2 months (range, 3.3 to 51.4 months). For all patients, the median times of local progression-free survival (LPFS), progression-free survival (PFS), and overall survival (OS) were 18.1, 10.3, and 14.2 months, respectively. The median time of LPFS between IC-CRT and CRT groups was similar (18.1 months vs. 18.3 months, p = 0.711). IC-CRT group had a higher trend in PFS (10.9 months vs. 4.1 months, p = 0.054) and had significantly higher OS (15.4 months vs. 9.5 months, p = 0.007) than CRT group. In multivariate analysis, the use of induction chemotherapy and tumor response were significant factors associated with OS (p < 0.05, each). During SIB-IMRT, toxicity of grade ≥3 was observed in 7 patients (14.9%) in all patients. Conclusions: CRT using SIB-IMRT is feasible and promising in LAPC patients.

• Korean Journal of Head & Neck Oncology
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• v.34 no.2
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• pp.11-15
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• 2018

Background/Objectives: The efficacy of radiotherapy alone versus chemoradiotherapy has been studied in patients with T2N0M0 laryngeal squamous cell carcinoma. Materials & Methods: Thirty nine patients with newly diagnosed T2N0M0 laryngeal squamous cell carcinoma were treated with either radiotherapy(RT group, 66-70Gy) or chemoradiotherapy(CRT group, cisplatin based concurrent chemoradiation with or without 2 cycles induction chemotherapy including cisplatin, $5-FU{\pm}$ docetaxel / radiation therapy same with above mentioned). The mean follow-up was 73.5 months. Results: The overall survival (OS), disease specific survival (DSS), disease free survival (DFS), and larynx preservation survival (LPS) at 5 years were 70%, 79%, 67%, and 71%. The complete response rate was 82.4% in RT group, and was 95.5% in CRT group. OS (57% vs 80%), DSS (69% vs 86%), DFS (52% vs 77%), and LPS (63% vs 77%) at 5 years were higher in CRT group than RT group, but it was not statistically significant. In subsite analysis, CRT group tends to improve DFS, compared to RT group, in glottic cancer (p=0.06). The toxicities were tolerable and no fatal case was observed in both groups. Conclusion: Chemoradiotherapy is effective as primary therapy for T2 laryngeal squamous cell carcinoma and showed manageable treatment induced toxicity.

• Journal of IKEEE
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• v.23 no.3
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• pp.1088-1091
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• 2019

In this paper, a real-time monitoring system for environmental safety by living area is proposed. The proposed system is designed to measure radiation, fine dust and basic living information (temperature) using fixed and mobile measuring equipment, and constitutes a web database that stores data received from the equipment. It also develops web programs for displaying received data on PCs and mobile phones. The results of testing the performance of the system by an authorized testing agency showed that the radiation measurement range was measured in the range of $10{\mu}Sv/h$ to 10mSv/h, which is comparable to the world's highest level, and that the accuracy was measured between ${\pm}6.7$ and ${\pm}8.7$ percent of the measurement uncertainty was measured and normal operation at or below the international standard of ${\pm}15$ percent. In addition, the temperature test was conducted on a section of $-20^{\circ}C$ to $50^{\circ}C$ and normal operation was confirmed in response to the temperature change. Stability of radiated electromagnetic waves was ensured by a suitable judgment. The product's testing in general and high and low temperature environments for about four months after the prototype was made confirmed to be more than five years of durability. The measurement range and accuracy of fine dust sensors are compared with those of companies that measure the air environment, and the performance level is similar through the air quality measurement register.

• 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.

• Journal of the Korea Society for Simulation
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• v.29 no.4
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• pp.33-46
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• 2020

The purpose of Electronic warfare is to disturbe, neutralize, attack, and destroy the opponent's electronic warfare weapon system or equipment. Suppression of Enemy Air Defense (SEAD) mission is aimed at incapacitating, destroying, or temporarily deteriorating air defense networks such as enemy surface-to-air missiles (SAMs), which is a representative mission supported by electronic warfare. This paper develops a simulator for analyzing the effectiveness of SEAD missions under electronic warfare support using C++ language based on the DEVS (Discrete Event Systems Specification) model, the usefulness of which has been proved through case analysis with examples. The SEAD mission of the friendly forces is carried out in parallel with SSJ (Self Screening Jamming) electronic warfare under the support of SOJ (Stand Off Jamming) electronic warfare. The mission is assumed to be done after penetrating into the enemy area and firing HARM (High Speed Anti Radiation Missile). SAM response is assumed to comply mission under the degraded performance due to the electronic interference of the friendly SSJ and SOJ. The developed simulator allows various combinations of electronic warfare equipment specifications (parameters) and operational tactics (parameters or algorithms) to be input for the purpose of analysis of the effect of these combinations on the mission effectiveness.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1251-1251
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• 2001

The routine analysis of milk chemical components is of major importance both for the management of animals in dairy farms and for quality control in dairy industries. NIRS technology is an analytical technique which greatly simplifies this routine. One of the most critical aspects in NIRS analysis of milk is sample preparation and analysis modes which should be fast and straightforward. An important difficulty when obtaining NIR spectra of milk is the high water content (80 to 90%) of this product, since water absorbs most of the infrared radiation, and, therefore, limits the accuracy of calibrating for other constituents. To avoid this problem, the DESIR system was set up. Other ways of radiation-sample interaction adapted for liquids or semi-liquids exist, which are practically instantaneous and with limited or null necessity of sample preparation: Transmission and Folded Transmission or Transflectance. The objective of the present work is to compare the precision and accuracy of milk calibration equations in two analysis modes: Reflectance (dry milk) and Folded Transmission (liquid milk). A FOSS-NIR Systems 6500 I spectrophotometer (400-2500 nm) provided with a spinning module was used. Two NIR spectroscopic methods for milk analysis were compared: a) folded transmission: liquid milk samples in a 0.1 pathlength sample cell (ref. IH-0345) and b) reflectance: dried milk samples in glass fibre filters placed in a standard ring cell. A set of 101 milk samples was used to develop the calibration equations, for the two NIR analysis modes, to predict casein, protein, fat and dry matter contents, and 48 milk samples to predict Somatic Cell Count (SCC). The calibrations obtained for protein, fat and dry matter have an excellent quantitative prediction power, since they present $r^2$ values higher than 0.9. The $r^2$ values are slightly lower for casein and SCC (0.88 and 0.89 respectively), but they still are sufficiently high. The accuracy of casein, protein and SCC equations is not affected by the analysis modes, since their ETVC values are very similar in reflectance and folded transmission (0.19% vs 0.21%; 0.16% vs 0.19% and 55.57% vs 53.11% respectively), Lower SECV values were obtained for the prediction of fat and dry matter with the folded transmission equations (0.14% and 0.25% respectively) compared to the results with the reflectance ones (0.43% and 0.34% respectively). In terms of accuracy and speed of analytical response, NIRS analysis of liquid milk is recommended (folded transmission), since the drying procedure takes 24 hours. However, both analysis modes offer satisfactory results.

• Journal of the Korean Geotechnical Society
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• v.22 no.9
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• pp.37-43
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• 2006

Dynamic numerical analysis of geotechnical problems requires a way to simulate the decrease of energy as the domain of interest gets larger. This phenomenon is usually referred to as radiation damping or geometric attenuation and it is distinguished from material damping in which elastic energy is actually dissipated by viscous, hysteretic, or other mechanism. The fact that the domain of analysis in numerical modeling must be chosen, however, causes a need for special attention at the boundary. This observation leads directly to the idea of determining the dynamic response of the interior region from a finite model consisting of the interior region subjected to a boundary condition which ensures that all energy arriving at the boundary is absorbed. This paper presents a simple methodology to simulate transmitting boundaries condition using viscoelastic infinite elements within the recently developed "OpenSees" finite element code. The methodology used here provides that the level of absorption for traveling waves is efficient enough for practical purposes, but unsatisfactory for the case of sharp incident angles. The effectiveness of the infinite elements for the absorption of incident waves at boundaries is evaluated via example analysis.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.116-122
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• 2002

Purpose : A randomized prospective study was conducted to compare the efficacy of early or late alternating schedules of radiotherapy, and carboplatin and ifosfamide chemotherapy in patients with limited-disease small cell lung cancer. Materials and Methods: From August 1993 to August 1996, a total of 44 patients with newly diagnosed, limited-disease small cell lung cancer, PS $H0\~2$, wt $loss<10\%$ were enrolled in a randomized trial which compared early alternating radiotherapy (RT)/chemotherapy (CT) and late alternating RT/CT. The CT regimen included ifosfamide $1.5\;g/m^2$ IV, d1-5 and carboplatin AUC 5/d IV, d2 peformed at 4 week intervals for a total of 6 cycles. RT (54 Gy/30 fr) was started after the first cycle of CT (early arm, N=22) or after the third cycle of CT (late arm, N=22) with a split course of treatment. Results : The pretreatment characteristics between the two arms were well balanced. The response rates in the early $(86\%)$ and late $(85\%)$ arm were similar. The median survival durations and 2-year survival rates were 15 months and $22.7\%$ in the early arm, and 17 months and $14.9\%$ in the late arm (p=0.47 by the log-rank test). The two-year progression free survival rates were $19.1\%$ in the early arm and $19.6\%$ in the late arm (p=0.52 by the log-rank test). Acute grade 3 or 4 hematologic and nonhematologic toxicities were similar between the two arms. Eighteen patients $(82\%)$ completed 6 cycles of CT in the early arm and 17 $(77\%)$ in the late arm. Four patients received less than 45 Gy of RT in the early arm and two in the late arm. There was no significant difference in the failure patterns. The local failure rate was $43\%$ in the early arm and $45\%$ in the late arm. The first site of failure was the brain in $24\%$ of the early arm patients compared to $35\%$ in the late arm (p=0.51). Conclusion : There were no statistical differences in the overall survival rate and the pattern of failure between the early and late alternating RT/CT in patients with limited-disease small cell lung cancer.