• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.4
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• pp.71-77
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• 2008

This paper presents a methodology for recovering the industrial radiographic images from the effects of nonlinear distortion. Analytical approach based on the inverse square law and Beer's law is developed in order to improve a mathematic model of nonlinear type. The geometric effect due to dimensions of the radioactive source appeals on the digitized images. The relation that expresses parameters values(angle, position, absorption coefficient, length, width and pixel account) is defined in this model, matching with the sample image. To perform the search for image recovery most similar to the model, a correction procedure is designed. The application of this method on the radiographic images of steel tubes is shown and recovered results are discussed.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.305-312
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• 2016

This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiogrphic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.

• Radiation Oncology Journal
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• v.24 no.4
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• pp.243-247
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• 2006

$\underline{Purpose}$: To evaluate the treatment results and prognostic factors of palliative radiation therapy in the patients with unresectable advanced pancreatic cancer. $\underline{Materials\;&\;Methods$: Thirty-seven evaluable patients with unresectable advanced pancreatic cancer who were treated by palliative radiation therapy for pain relief at the Department of Radiation Oncology, Kangnam St. Mary's hospital, the Catholic University of Korea between March 1984 and February 2005 were analysed retrospectively. There were 22 men and 15 women. Age at diagnosis ranged from 30 to 80 (median 57) years. Twelve patients (32.4%) had liver metastases and 22 patients (59.5%) had lymph node metastases. Radiation therapy was delivered to primary tumor and regional lymph nodes with $1{\sim}2\;cm$ margin, and total dose was $3,240{\sim}5,580\;cGy$ (median 5,040 cGy). Chemotherapy with radiotherapy was delivered in 30 patients (81%) with 5-FU alone (21 patients) or gemcitabine (9 patients). The follow-up period ranged from 1 to 44 months. Survival and prognostic factors were analysed using Kaplan-Meier method and log-rank test respectively. $\underline{Results}$: Overall mean and median survival were 11 and 8 months and 1-year survival rate was 20%. Among 33 patients who were amenable for response evaluation, 7 patients had good response and 22 patients had fair response with overall response rate of 87.9%. Mild to moderate toxicity were observed in 14 patients with nausea, vomiting, and indigestion, but severe toxicity requiring interruption of treatment were not observed. Chemotherapy didn't influence the survival and symptomatic palliation, but the group containing gemcitabine showed a tendency of longer survival (median 12 months) than 5-FU alone group (median 5.5 months) without statistical significance (p>0.05). The significant prognostic factors were Karnofsky performance status and liver metastasis (p<0.05). Age, sex, tumor location, lymph node metastasis, and CA 19-9 level did not show any prognostic significance (p>0.05). $\underline{Conclusion}$: Radiation therapy was effective for symptomatic palliation in the patients with unresectable advanced pancreatic cancer and would play an important part in the survival benefit with gemcitabine or other targeted agents.

• Radiation Oncology Journal
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• v.28 no.1
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• pp.9-15
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• 2010

Purpose: This study was performed to examine the neck failure patterns after a complete response (CR) to definitive radiotherapy for advanced head and neck cancer patients, as well as evaluate the clinical significance of the results of this study. Materials and Methods: Between 1987 and 2008, the clinical data of patients who had been treated with radical radiotherapy for primary squamous cell carcinomas and enlarged cervical lymph nodes was analyzed retrospectively. Ultimately, the cases that showed CR of the cervical lymph node lesions to full-dose radiotherapy were included in this study. The recurrent rate and sites in the cervical lymphatic area were evaluated periodically by radiologic imaging studies, along with some factors which might have affected the rate of recurrence. Results: A total of 73 patients who achieved CR in neck area after radiotherapy were included in this study. The rate of subsequent neck failure among those patients was 19.2%. There was only a 5.5% failure rate in the 55 patients who underwent radiotherapy in their primary site. Eighty percent of the recurrent cases were found within 3 years (median follow-up, 68 months). The majority of neck recurrent cases (47%) were accompanied with the failure of the primary lesions. The initial response of the primary site and the method of radiotherapy simulation were significant prognostic factors associated with the nodal recurrence rate. Conclusion: The recurrence rate of cervical nodes in patients with CR to radiotherapy in the primary site and neck area was about 5%. These patients could be followed up with close observation without a planned neck dissection.

• Radiation Oncology Journal
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• v.19 no.4
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• pp.369-380
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• 2001

Purpose : By developing on-line statistics program to record the information of radiation oncology to share the information with internet. It is possible to supply basic reference data for administrative plans to improve radiation oncology. Materials and methods : The information of radiation oncology statistics had been collected by paper forms about 52 hospitals in the past. Now, we can input the data by internet web browsers. The statistics program used windows NT 4.0 operation system, Internal Information Server 4.0 (IIS4.0) as a web server and the Microsoft Access MDB. We used Structured Query Language (SQL), Visual Basic, VBScript and JAVAScript to display the statistics according to years and hospitals. Results : This program shows present conditions about man power, research, therapy machines, technics, brachytherapy, clinic statistics, radiation safety management, institution, quality assurance and radioisotopes in radiation oncology department. The database consists of 38 inputs and 6 outputs windows. Statistical output windows can be increased continuously according to user's need. Conclusion : We have developed statistics program to process all of the data in department of radiation oncology for reference information. Users easily could input the data by internet web browsers and share the information.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.185-191
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• 1989

The combined effects of heat treatment and ${\gamma}-irradiation$ on the inactivation of major lactic acid bacteria associated with Kimchi fermentation were investigated. The radiosensitivities $(D_{10}\;values)$ of lactic acid bacteria in case of a single treatment of irradiation were 0.61 kGy in Lactobacillus brevis, 0.60 kGy in Lactobacillus plantarum, 0.50 kGy in Leuconostoc mesenteroides, 0.4 kGy in Pediococcus cerevisiae, 0.39 kGy in Streptococcus faecalis. The heat sensitization $(D_{min}\;values)$ by a single treatment of heat ranged 9.2-15.6 at $50^{\circ}C$ and 3.7-5.5 at $60^{\circ}C$. Synegistic effects were shown in the radiosensitivities of Streptococcus faecalis, Pediococcus cerevisiae, Lactobacillus plantarum, and Lactobacillus brevis by the combined treatment(Dose multiplying factors ranged $1.20{\sim}1.56$). It seems, therefore, that the combined treatment can be applied to the radiation preservation of Kimchi, minimizing the side-effects like physical changes induced by the high dose irradiation or heat treatment.

• Journal of the Korean Society of Radiology
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• v.6 no.3
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• pp.197-200
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• 2012

This research investigated Takju alcohol content in the case of irradiation changes in the statistical analysis was performed to visually. Lower proof alcohol fermentation Takju traditional and largely maintained 6 degrees, from the heat sterilization process is controlled through the distribution period. Most of the existing irradiation is focused on preservation of the product, but this study of the quality characteristics of the mechanical changes in alcohol was to seek value. Takju Celsius to $15^{\circ}C$, while maintaining the experiment were kept in the state. Radiation devices Varian Clinac ix, 2010 (Max. 10MV) using the field size $150mm{\times}150mm$, SSD 100 cm at 40kVp 1, 4, 7, 10, 13, 15, 20Gy were vertical. KJELDAHL APPARATUS, C-H6 Alcohol frequency was measured using. The results according to the change of the radiation dose alcohol did not show the sudden change of frequency, were observed at similar levels decreased. This study simply due to the radiation dose to be served, but to find the change in the future with a greater sense of quality changes should be considered.

• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.65-72
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• 2015

The basic concepts of radiation-induced skin damage have been established, the biological mechanism has not been studied. In this study, we have examined the effects of gamma rays on skin injury and cyclooxygenase(COX)-2 expression. Gamma irradiation induced clinicopathological changes in a dose- and time-dependent manner in mini-pig skin. The histological changes were consistent with the changes in gross appearance at 12 weeks after irradiation. After three days' irradiation, apoptotic cells in the basal layer were found more frequently in irradiated skin than in normal skin, with the magnitude of the effect being dose-dependent. The thickness of the epidermis transiently increased 3 days after irradiation, and then gradually decreased, although changes in the epithelial thickness of the irradiated field were not observed with irradiation doses over 50 Gy. In the epithelium, there was an initial degenerative phase, during which the rate of basal cell depletion was dependent on the radiation dose (20-70 Gy). One week after irradiation, COX-2 expression was mostly limited to the basal cell layer and was scattered across these cells. High COX-2 expression was detected throughout the full depth of the skin after irradiation. The COX-2 protein is upregulated after irradiation in mini-pig skin. These histological changes associated with radiation exposure dose cause the increased COX-2 expression in a dose-dependent fashion.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.471-476
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• 2022

The purpose of this study was to study the probability of cancer occurrence due to photoneutron dose exposure of the colon and thyroid gland, which are normal organs, in 3D CRT, IMRT 5 portals, and IMRT 9 portals, which are radiotherapy methods for prostate cancer. The total prescribed dose for prostate cancer was 6600 cGy, 220 cGy per dose, and 30 divided irradiations were applied for the total number of times. After setting up the Rando phantom on the treatment table (couch) of the medical linear accelerator used in the experiment, an optically stimulated luminescence albedo neutron dosimeter was placed on the corresponding area of the large intestine and thyroid gland of the phantom for measurement. During 3D CRT of prostate cancer, the probability of secondary cancer due to photoneutron dose to the colon and thyroid gland, which are normal organs, was 1.8 per 10,000 people. And IMRT 5 portals were 8.7 per 10,000 people, which was about 5 times larger than 3D CRT. IMRT 9 portals derived the result that there is a probability that 1.2 people per 1,000 people will develop cancer. Based on this study, the risk of secondary radiation exposure due to the dose of photoneutrons generated during radiation therapy is studied, and it is thought that it will be used as useful data for radiation protection in relation to the stochastic effect of radiation in the future.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.243-248
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• 2023

This study aims to analyze the secondary carcinogenesis rate caused by exposure of organs at risk of damage using a glass dosimeter during radiosurgery in vestibular schwannoma disease. Using a pediatric phantom of human tissue equivalent material, the volume of the tumor was set to a total of three volumes: 0.506 cm³, 1.008 cm³, and 2.032 cm³, and a radiosurgery plan was established with an average dose of 18.4 ± 3.4 Gy. After mounting the human body phantom on the table of surgical equipment, glass dosimeters were placed on the right eye, left eye, thyroid gland, thymus, right lung, and left lung to measure the exposure dose, respectively. In this study, the incidence of secondary cancer due to exposure to damaged organs during gamma knife radiosurgery in vestibular schwannoma disease with the largest tumor volume of 2.032 cm³ was measured with a glass dosimeter. This study studies the risk of secondary radiation exposure dose that can occur during stereotactic radiosurgery, and it is considered that it will be used as basic data in the field of radiation damage related to the stochastic effect of radiation in the future.