• Journal of the Korean Society of Radiology
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• v.83 no.4
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• pp.783-791
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• 2022

The radiation emitted during radiological examinations can be harmful to the human body, but the technique is still used because it is helpful to the patient. Therefore, radiologic examinations must follow radiation protection principles such as justification and optimization, and only minimal required re-examinations should be performed. Proper use of radiation in the medical field can be achieved by proper education of individuals from multiple medical fields.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.182-186
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• 2014

Recently, the use of panoramic radiography has shown a constant increase, and significant research is underway. However, radiation exposure attracts less attention in dental radiography than in other types of radiography. We used an OSLD for measurement of the entrance skin dose in eyeballs and the thyroid region, both of which are not covered by examinations but are included in radiographical regions and are sensitive to radiation, as well as orally in Incheon and reported the results. The entrance skin dose was 0.0282 mSv on average for the oral region, and 0.0259 mSv on average for the eyeball, and 0.0261mSv on average, for thyroid gland. While there is no proper shielding method for the eyeball, a thyroid protector is not used by most hospitals and most hospitals are equipped with an apron and a thyroid protector separately; thus, it is necessary to use an integration of an apron and a thyroid protector and medical device manufacturers need to develop a method for controlling the length of the slit in the slit-type area of radiation occurrence in order to reduce unnecessary exposure.

• Progress in Medical Physics
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• v.31 no.4
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• pp.194-204
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• 2020

This study investigated and analyzed the Korean and international status of radioactive waste management for medical linear accelerators (linacs) and proceed prior research to suggest radiation safety regulations and guidelines for the safe use of radiation. We analyzed the number of linacs installed in the radiation oncology departments of 103 institutions. In addition, we analyzed the procedures and standards for disposal in Korea and foreign countries. For foreign countries, we analyzed the status based on reports from the United States, Japan, Europe, and Canada. A total of 182 linacs are installed in Korea and 95% of them use more than 10 MV of energy. In Korea, standards for managing radioactive waste from a linac, disposal procedures, and clearance criteria have yet to be established. Therefore, radioactive waste is disposed of in different ways depending on the hospitals where they originate. Japan, the US, and Canada have recommended clearance levels and procedures for linacs. Other countries have provided management guidelines for research or large-scale accelerators, but not for medical purposes. In this study, we investigated the management of radioactive waste from medical linacs in Korea and abroad. Several foreign countries have suggested a clearance level and criteria for disposing of waste storage drums. For the safe management of medical linacs, it is necessary to establish safety management regulations. In Korea, standards for disposal, such as radiation or dose limits, are required for medical linacs. A system for clearance when disposing at a medical institution should be created.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1744-1749
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• 2018

This study investigated the feasibility of synthesizing GNPs using synchrotron radiation X-ray for use as a radiosensitizer in radiotherapy, and examined the morphology of the GNPs. Different concentration ratios of 4-mM gold precursor aqueous solution and 4-mM $NaHCO_3$ were mixed. This gold precursor aqueous solution was continuously irradiated with synchrotron radiation in the 4B X-ray microdiffraction beamline of Pohang Light Source (PLS)-II in Korea. The SEM, EDS, TEM, and XRD spectra of the GNPs synthesized using the synchrotron radiation were investigated. The GNPs synthesized using the synchrotron radiation were nanocrystals predominantly in the (111) direction of the face-centered cubic structure. We found that the shape of the gold nanoparticles was icosahedron at the molar concentrations of 0.25 mM:0.25 mM and 0.5 mM:0.5 mM mixed with 4 mM $HAuCl_4{\cdot}3H_2O$ and 4 mM $NaHCO_3$ solutions.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.232-235
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• 2004

Since ready-to-use (RTU) products are not fully cooked, the shelf-life of the product is comparably short and the products are easily spoiled when contaminated with food-borne pathogens. Low-dose gamma irradiation of 0.5, 1, or 2 kGy effectively reduced the total aerobic bacterial counts in 2 Korean manufactured RTU products by 1.63 to 2.95 log CFU/g during cold storage. Irradiation at 2 kGy reduced the psychrotrophic bacterial counts in most of the samples to below the limit of detection (< log CFU/g). Irradiation at 0.5 kGy completely eliminated Escherichia coli from the commercial RTU samples.

• The Journal of Korean Society for Radiation Therapy
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• v.9 no.1
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• pp.64-70
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• 1997

The goal of radiation treatment planning is to deliver the dose to the patient within $5\%$ of that prescribed. We have often encountered the situation that the area which have not only several irregular contours but also tissue heterogeneities should be treated. With conventional devices such as wedges, missing tissue compensator. there are some limitations to achieve the uniform dose distribution in treatment volume. The use of CT simulator, 3-D planning system, computer-controlled milling machine enables it to deliver the dose uniformally. This report includes the whole procedure which have patient data acquisition 3D planning, computer-controlled milling, performance verification of 3D compensator, and TLD evaluation. We applied it for the treatment of head and heck cancer only. In Spite of the irregular contour and different electron density of tessue, we have achieved the uniformity of the dose distribution within ${\pm}3\%$ relatively. Although there are some problems which are not only verification of performance but uncertainties of using the new treatment device, we believe that the improvement of dosimetry will eliminate the uncertainties of that application. so the other lesions besides head and neck can will be ale to use the 3D compensator to achieve the dose uniformity

• Journal of Radiation Industry
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• v.2 no.1
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• pp.1-7
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• 2008

Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as biomimetic actuators and artificial muscles. In this study, poly (vinyl alcohol)(PVA) grafted acrylic acid monomer (PVA-g-AAc) hydrogels were prepared by $^{60}Co$ ${\gamma}-ray$ irradiation and their properties such as degree of grafting and weight swelling in electrostimulation as an artificial muscle and actuator were investigated.

• Radiation Oncology Journal
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• v.35 no.1
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• pp.55-64
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• 2017

Purpose: The outcomes and toxicities of locoregionally recurrent non-small-cell lung cancer (NSCLC) patients treated with curative radiotherapy were evaluated in the modern era. Materials and Methods: Fifty-seven patients receiving radical radiotherapy for locoregionally recurrent NSCLC without distant metastasis after surgery from 2004 to 2014 were reviewed. Forty-two patients were treated with concurrent chemoradiotherapy (CCRT), and 15 patients with radiotherapy alone. The median radiation dose was 66 Gy (range, 45 to 70 Gy). Lung function change after radiotherapy was evaluated by comparing pulmonary function tests before and at 1, 6, and 12 months after radiotherapy. Results: Median follow-up was 53.6 months (range, 12.0 to 107.5 months) among the survivors. The median overall survival (OS) and progression-free survival (PFS) were 54.8 months (range, 3.0 to 116.9 months) and 12.2 months (range, 0.8 to 100.2 months), respectively. Multivariate analyses revealed that single locoregional recurrence focus and use of concurrent chemotherapy were significant prognostic factors for OS (p = 0.048 and p = 0.001, respectively) and PFS (p = 0.002 and p = 0.026, respectively). There was no significant change in predicted forced expiratory volume in one second after radiotherapy. Although diffusing lung capacity for carbon monoxide decreased significantly at 1 month after radiotherapy (p < 0.001), it recovered to pretreatment levels within 12 months. Acute grade 3 radiation pneumonitis and esophagitis were observed in 3 and 2 patients, respectively. There was no chronic complication observed in all patients. Conclusion: Salvage radiotherapy showed good survival outcomes without severe complications in postoperative locoregionally recurrent NSCLC patients. A single locoregional recurrent focus and the use of CCRT chemotherapy were associated with improved survival. CCRT should be considered as a salvage treatment in patients with good prognostic factors.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.95-101
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• 1999

When a metal oxide field effect transistor (MOSFET) is exposed to ionizing radiation, electron/hole pairs are generated in its oxide layer. The slow moving holes of them are trapped in the oxide layer of p-MOSFET and appear as extra charges that change the characteristics of the transistor. The radiation-induced charges directly impact the threshold (turn-on) voltage of the transistor. This paper describes the use of the radiation-induced threshold voltage change as an accumulated radiation dose monitoring sensor. Two kinds of commercial p-type MOSFETS were tested in a Co-60 gamma irradiation facility to see their capabilities as a radiation dosimeter. We found that the transistors showed good linearity in their threshold voltage shift characteristics with radiation dose. The results demonstrate the potential use of commercial p-MOSFETS as inexpensive radiation sensors for the first time.

• Radiation Oncology Journal
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• v.36 no.4
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• pp.265-275
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• 2018

Cancer is a complex multifaceted illness that affects different patients in discrete ways. For a number of cancers the use of chemotherapy has become standard practice. Chemotherapy is a use of cytostatic drugs to cure cancer. Cytostatic agents not only affect cancer cells but also affect the growth of normal cells; leading to side effects. Because of this, radiotherapy gained importance in treating cancer. Slaughtering of cancerous cells by radiotherapy depends on the radiosensitivity of the tumor cells. Efforts to improve the therapeutic ratio have resulted in the development of compounds that increase the radiosensitivity of tumor cells or protect the normal cells from the effects of radiation. Amifostine is the only chemical radioprotector approved by the US Food and Drug Administration (FDA), but due to its side effect and toxicity, use of this compound was also failed. Hence the use of herbal radioprotectors bearing pharmacological properties is concentrated due to their low toxicity and efficacy. Notably, in silico methods can expedite drug discovery process, to lessen the compounds with unfavorable pharmacological properties at an early stage of drug development. Hence a detailed perspective of these properties, in accordance with their prediction and measurement, are pivotal for a successful identification of radioprotectors by drug discovery process.