• Journal of radiological science and technology
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• v.42 no.3
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• pp.223-229
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• 2019

In order to reduce the radiation exposure dose of the patient and to obtain accurate diagnosis results, the quality control of the diagnostic radiation generator must be conducted periodically In particular, bone density test equipment could be influenced by many factors, and it is far more important because inaccurate measurement would eventually affect the result value. However, the cross-correction phantom of DXA equipment is poorly penetrated due to lack of awareness of the industry and the high cost. Therefore, this study developed a BMD phantom using a 3D printer and Korean BMD phantom with low cost by cross analyzing Korean BMD value from The Korean National Health and Nutrition Examination Survey and evaluated it. The L1, L2, and L3 BMD values of phantoms produced with the 3D printer were measured to be $0.887{\pm}0.006g/cm^2$, $0.927{\pm}0.006g/cm^2$, and $0.960{\pm}0.005g/cm^2$, at 215 mm height and $0.882{\pm}0.011g/cm^2$, $0.914{\pm}0.005g/cm^2$, $0.933{\pm}0.008g/cm^2$ at 155 mm height displaying statistically significant relevance. The result suggests that a proper quality control and cross calibration of DXA device be possible and expected to be an essential data for various medical phantom manufacture development using 3D printer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5587-5591
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• 2012

Objective: This study was performed to evaluated the efficacy and safety of continuous infusional paclitaxel and 5-Fu as first-line chemotherapy in patients with advanced esophageal squamous cell cancer (ESCC). Methods: A total of 22 patients with advanced esophageal squamous cell cancer with no indications for surgery and radiation therapy, or recurrent patients were enrolled from October 2008 to November 2010. All were treated with PTX 20 $mg/m^2$ was administered through a 16 hours continuous intravenous infusion on days 1 to 3, 8 and 9. DDP 3.75 $mg/m^2$ was given on days 1 to 4 and 8 to 11, continuous infusional 5-FU over 24-hours on days 1 to 5 and 8 to 12 at a dose of 375 $mg/m^2$, and folacin 60 mg orally synchronized with 5-Fu. The treatment was repeated every 21 days for at least two cycles. Results: 22 cases of all enrolled patients could be evaluated for the effect of treatment: 2 cases were CR, 9 cases PR, 5 cases SD and 2 cases PD, giving an overall response rate of 68.2%(15/22). The median time to progression was 7.0 months. The adverse reactions related to chemotherapy were tolerable; the most common toxic effects were marrow depression, alopecia, and fatigue. Conclusion: Low-dose continuous infusional PTX over 16-hours and 5-fu over 24-hours is a promising regimen with good tolerability in treating patients with advanced esophageal squamous cell cancer.

• Nuclear Engineering and Technology
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• v.2 no.4
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• pp.229-239
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• 1970

Various thermoluminescent properties of Korean natural quartz for possible use in ${\gamma}$-ray dosimetry has been studied. If the heating is exactly linear, ${\gamma}$-irradiated radiation sensitive (type 1) $\alpha$-quartz can yield a glow curve of single peak, hence glow peak height could be taken as a ${\gamma}$-dose for its dosimetry. Quartz crystal dosimeter exhibited the linearity of thermoluminescent intensity in the range from about 2$\times$10$^{3}$R to 2$\times$10$^{6}$ R, and also had an advantage of low fading because of the high peak temperature (300$\pm$4$0^{\circ}C$). The pulverized quartz sample having the grain size of 0.3<ø<0.9mm showed the linearity of T. L. intensity in the range from 50R to 2$\times$10$^3$R. Therapeutic application of the pulverized sample on the correct measurement of the absorbed dose in a body region of a cancer patient seems to be successful.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.11
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• pp.981-987
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• 2014

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a MOSFET (metal-oxide semiconductor field effect transistor), a PWM-IC (pulse width modulation-integrated circuit) controller, inductor, capacitor, etc. It is shown that the variation of threshold voltage and the breakdown voltage in the electrical characteristics of MOSFET occurs by radiation effects in TID (Total Ionizing Dose) testing at the low energy ${\gamma}$ rays using $^{60}Co$, and 5 heavy ions make the gate of MOSFET broken in SEGR (Single Event Gate Rupture) testing. TID testing on MOSFET is accomplished up to the total dose of 40 krad, and the cross section($cm^2$) versus LET(MeV/mg/$cm^2$) in the MOSFET operation is studied at SEGR testing after implementation of the controller board.

• Journal of Trauma and Injury
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• v.35 no.1
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• pp.12-18
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• 2022

Purpose: Pedicle screw fixation provides 3-column stabilization, multidimensional control, and a higher rate of interbody fusion. Although computed tomography (CT) is recommended for the postoperative assessment of pedicle screw fixation, its use is limited due to the radiation exposure dose. The purpose of this preliminary retrospective study was to assess the clinical usefulness of low-dose mobile cone-beam CT (CBCT) for the postoperative evaluation of pedicle screw fixation. Methods: The author retrospectively reviewed postoperative mobile CBCT images of 15 patients who underwent posterior pedicle screw fixation for spinal disease from November 2019 to April 2020. Pedicle screw placement was assessed for breaches of the bony structures. The breaches were graded based on the Heary classification. Results: The patients included 11 men and four women, and their mean age was 66±12 years. Of the 122 pedicle screws, 34 (27.9%) were inserted in the thoracic segment (from T7 to T12), 82 (67.2%) in the lumbar segment (from L1 to L5), and six (4.9%) in the first sacral segment. Although there were metal-related artifacts, the image of the screw position (according to Heary classification) after surgery could be assessed using mobile CBCT at all levels (T7-S1). Conclusions: Mobile CBCT was accurate in determining the location and integrity of the pedicle screw and identifying the surrounding bony structures. In the postoperative setting, mobile CBCT can be used as a primary modality for assessing the accuracy of pedicle screw fixation and detecting postoperative complications.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.148-152
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• 2007

In this paper, we have synthesized $Gd_2O_3:Eu^{3+}$ nano phosphor particle using a low temperature solution-combustion method. We have investigated the structure and the luminescent characteristic as the sintering temperature and europium concentration. From XRD(X-ray diffraction) and SEM(scanning electron microscope) results, we have verified that the phosphor particle was fabricated a spherical shape with $30{\sim}40nm$ particle size. From the photoluminescence results, the strong peak exhibits at 611 um and the luminescent intensity depends on europium concentration. $Gd_2O_3:Eu$ fine phosphor particle has shown excellent luminescent efficiency at 5 wt% of europium concentration. The phosphors calcinated at $500^{\circ}C$ have possessed the x-ray peaks corresponding to the cubic phase of $Gd_2O_3$. As calcinations temperature increased to $700^{\circ}C$, the new monoclinic phase has identified except cubic patterns. From the luminescent decay time measurements, mean lifetimes were $2.3{\sim}2.6ms$ relatively higher than conventional bulk phosphors. These results indicate that $Gd_2O_3:Eu$ nano phosphor is possible for the operation at the low x-ray dose, therefore, the application as medical imaging detector.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.355-363
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• 1982

In order to develop the commercial storage method of potatoes by irradiation combined with natural low temperature, storage room($450{\times}650{\times}250cm$; year round temperature change, $2-17^{\circ}C;\;70-85%\;R.H.$) on a batch scale followed by irradiation with optimum dose level. Irish cobbler and Shimabara were 100% sprouted after 3 months storage in control, whereas in 15 Krad irradiated group, sprouting was completely inhibited at Irish cobbler for 9 months storage, and at Shimabara for 12 months. The extent of loss due to rot attack after 9 months storage was 6% in control, 6-8% in 10-15 Krad irradiated group at Irish cobbler and weight loss was 16.5% in control, 5.1-5.6% in irradiated group, whereas rotting rate of Shimabara after 12 months storage was 100% in control, 15% in irradiated group and the weight loss of its was 12.6% in control, $7.3{\sim}7.4%$ in irradiated group. The moisture content in whole storage period of two varieties were $72{\sim}82%$ without remarkable changes. The total sugar and ascorbic acid contents were slightly decreased according to the dose increase and elapse of storage period, whereas reducing sugar content was increased. Irish cobbler was 90% marketable after 9 months storage and 85% in Shimabara after 12 months storage.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.311-329
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• 1986

The experimental exposure of animals to sources of ultraviolet radiation (UVR) which emit their energy primarily in the UVB region (280-320nm) is known to result in a number of well-described changes in the recipient's immune competence. Two such changes include a depressed capacity to effectively respond immunologically to transplants of syngeneic UVR tumors and a markedly reduced responsiveness to known inducers of delayedtype (DTH) and contact hypersensitivity (CH) reactions. The results of experiments that were designed to elucidate the mechanisms responsible for UVR-induced immunomodulation have implicated: 1) an altered pattern of lymphocyte recirculation, 2) suppressor T cells(Ts), 3) deviations in systemic antigen presenting cell (APC) potential. 4) changes in the production of interleukin-1-like molecules, and 5) the functional inactivation of epidermal Langerhans cells in this process. The exposure of skin to UVR, therefore, causes a number of both local and systemic alterations to the normal host immune system. In spite of this seeming complexity and diversity of responses, our recent studies have established that each of the UVR-mediated changes is probably of equal importance to creating the UVR-induced immunocompromised state. Normal animals were exposed to low dose UVR radiation on their dorsal surfaces under conditions where a $3.0\;cm^2$ area of skin was physically protected from the light energy. Contact sensitization of these animals with DNFB, to either the irradiated or protected back skin, resulted in markedly reduced CH responses. This was observed in spite of a normal responsiveness following the skin sensitization to ventral surfaces of the UVR-exposed animals. Systemic treatment of the low dose UVR recipients with the drug indomethacin (1-3 micrograms/day) during the UVR exposures resulted in a complete reversal of the depressions observed following DNFB sensitization to "protected" dorsal skin while the altered responsiveness found in the group exposed to the skin reactive chemical through directly UVR-exposed sites was maintained. These studies implicate the importance of EC as effective APC in the skin and also suggest that some of the systemic influences caused by UVR exposure involve the production of prostaglandins. This concept was further supported by finding that indomethacin treatment was also capable of totally reversing the systemic depressions in CH responsiveness caused by high dose UVR exposure (30K joules/$m^2$) of mice. Attempts to analyze the cellular mechanisms responsible established that the spleens of all animals which demonstrated altered CH responses, regardless of whether sensitization was through a normal or an irradiated skin site, contained suppressor cells. Interestingly, we also found normal levels of T effector cells in the peripheral lymph nodes of the UVR-exposed mice that were contact sensitized through normal skin. No effector cells were found when skin sensitization took place through irradiated skin sites. In spite of such an apparent paradox, insight into the probable mechanisms responsible for these observations was provided by establishing that UVR exposure of skin results in a striking and dose-dependent blockade of the efferent lymphatic vessels in all peripheral lymph nodes. Therefore, the afferent phases of immune responses can apparently take place normally in UVR exposed animals when antigen is applied to normal skin. The final effector responses, however, appear to be inhibited in the UVR-exposed animals by an apparent block of effector cell mobility. This contrasts with findings in the normal animals. Following contact sensitization, normal animals were also found to simultaneously contain both antigen specific suppressor T cells and lymph node effector cells. However, these normal animals were fully capable of mobilizing their effector cells into the systemic circulation, thereby allowing a localization of these cells to peripheral sites of antigen challenge. Our results suggest that UVR is probably not a significant inducer of suppressor T-cell activity to topically applied antigens. Rather, UVR exposure appears to modify the normal relationship which exists between effector and regulatory immune responses in vivo. It does so by either causing a direct reduction in the skin's APC function, a situation which results in an absence of effector cell generation to antigens applied to UVR-exposed skin sites, inhibiting the capacity of effector cells to gain access to skin sites of antigen challenge or by sequestering the lymphocytes with effector cell potential into the draining peripheral lymph nodes. Each of these situations result in a similar effect on the UVR-exposed host, that being a reduced capacity to elicit a CH response. We hypothesize that altered DTH responses, altered alloresponses, and altered graft-versus-host responses, all of which have been observed in UVR exposed animals, may result from similar mechanisms.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.427-432
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• 2017

This study describes the design and implementation of SHF band Downconverter Digital Satellite Communication. The SHF band Downconverter unit consists of PLDRO and Frequency converter. In Frequency converter, microstrip BPF and LPF designed through the pre EM simulation are implemented to minimize the unwanted spurious in Frequency converter. Through the pre-simulation analysis of space environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Downconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Downconverter after production.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.1
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• pp.76-81
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• 1999

Aneurysmal bone cysts are uncommon bony lesions of the spine. Approximately 3-20% of the aneurysmal bone cysts occur in the spine, predominantly in the lumbar region, but they may occur at the any level of the spine. These lesions commonly arise from the neural arch and occasionally invade the pedicle and the vertebral body. The clinical diagnosis of a spinal lesion can be very difficult in the early stages of the disease because specific symptoms and signs are usually absent or only amount to back pain. However, depending on the level of involvement and the extent of neurological compression, a wide variety of neurological symptoms and signs may appear, ranging from mild radicular symptoms to complete paraplegia or tetraplegia. Available treatment options include complete excision or curettage of the lesion with bone graft, but where excision cannot be achieved, low dose radiation or arterial embolization may be used. We report a case of aneurysmal bone cyst in the pedicle of the T10 spine with nonstructural scoliosis of $40^{\circ}$ Cobb's angle which was treated successfully with only curettage of the lesion.