• Journal of Radiation Protection and Research
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• v.10 no.1
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• pp.50-63
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• 1985

A derivation of new release limit, named Derived Release Limit(DRL), into the atomsphere from a reference nuclear power plant has been performed on the basis of the new system of dose limitation recommended by the ICRP, instead of the (MPC)a limit which has been currently used until now as a general standard for radioactive effluents in Korea. In DRL Calculation, a Concentration Factor Method was applied, in which the concentrations of long-term routinely released radionuclides were in equilibrium with dose in environment under the steady state condition. The analytical model used in the exposure pathway analysis was the one which has been suggested by the USNRC and the exposure limits applied in this analysis were those recommended by the USEPA lately. In the exposure pathway analysis, all of the pathways are not considered and some may be excluded either because they are not applicable or their contribution to the exposure is insignificant compared with other pathways. In case, the environmental model developed in this study was applied to the Kori nuclear power plant as the reference power plant, the highest DRL value was calculated to be as $9.10{\times}10^6Ci/yr$ for Kr-85 in external whole body exposure from the semi-infinite radioactive cloud, while the lowest DRL value was observed 3.64Ci/yr for Co-60 in external whole body exposure from the contaminated ground, by the radioactive particulates. The most critical exposure pathway to an individual in the unrestricted area of interest (Kilchun-Ri, 1.3 km to the north of the release point) seems to be the exposure pathway from the contaminated ground and the most critical radionuclide in all pathways appears to be Co-60 in the same pathway. When comparing the actual release rate from KNU-l in 1982 with the DRL's obtained here the release of radionuclides from KNU-1 were much lower than the DRL's and it could be conclued that the exposure to an individual had been kept below the exposure limits recommended by the USEPA.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.173-180
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• 2009

Purpose: To investigate the role of radiotherapy for squamous cell carcinomas of the external auditory canal and middle ear. Materials and Methods: A series of 35 patients who were treated at a single institution from 1981 through 2007 were retrospectively analyzed. Thirteen patients were treated by radiotherapy alone; four by surgery only and 18 by a combination of surgery and radiotherapy. The total radiation dose ranged from 39~70 Gy (median, 66 Gy) in 13~35 fractions for radiotherapy alone and 44~70 Gy (median, 61.2 Gy) in 22~37 fractions for the combined therapy. Clinical end-points were the cause of specific survival (CSS) and local relapse-free survival (LRFS). The median follow-up time was 2.8 years (range, 0.2~14.6 years). Results: The 3-year CSS and LRFS rate was 80% and 63%, respectively. Based on a univariate analysis, performance status and residual disease after treatment had a significant impact on CSS; performance status and histologic grade for LRFS. Patients treated by radiotherapy alone had more residual disease following the course of treatment compared to patients treated with the combined therapy; 69% vs. 28%, respectively. Conclusion: Our results suggest that radiation alone was not an inferior treatment modality for CSS compared to the combined therapy for squamous cell carcinoma of the external auditory canal and middle ear. However, local failure after radiotherapy is the main issue that will require further improvement to gain optimal local control.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.267-275
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• 1993

Eighty five patients of oral cavity cancer, treated with radiation at the Department of Therapeutic Radiology, Korea Cancer Center Hospital, during the period from March 1985 to September 1990 were analyzed retrospectively. Among 85 patients, 37 patients were treated with radiation only and 48 patients were treated with radiation following surgery. And 70 patients received external irradiation only by $^{60}Co$ with or without electron, the others were 7 patients for external irradiation plus interstitial implantation and 8 patients for external irradiation plus oral cone electron therapy. Primary sites were mobile tongue for 40 patients, mouth floor for 17 patients, palate for 12 patients, gingiva including retromolar trigone for 10 patients, buccal mucosa for 5 patients, and lip for 1 patient. According to pathologic classification, squamous cell carcinoma was the most common (77 patients). According to AJC TNM stage, stage I + II were 28 patients and stage III+IV were 57 patients. Acturial overall survival rate at 3 years was $43.9\%,$ 3 year survival rates were $60.9\%$ for stage I + II, and $23.1\%$ for stage III+IV, respectively. As a prognostic factor, primary T stage was a significant factor (p<0.01). The others, age, location, lymph node metastasis, surgery, radiation dose, and cell differentiation were not statistically significant. Among those factors, radiation plus surgery was more effective than radiation only in T3+T4 or in any N stage although it was not statistically sufficient (p<0.1). From those results, it was conclusive that definitive radiotherapy was more effective than surgery especially In the view of pertainig of anatomical integrity and function in early stage, and radiation plus surgery was considered to be better therapeutic tool in advanced stage.

• Radiation Oncology Journal
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• v.5 no.2
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• pp.97-104
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• 1987

From January 1970 through December 1984, 15 patients with sinonasal Non-Hodgkin's lymphoma combined to the head and neck were treated by external irradiation.13 patients were stage It and 2 were stage IIE by Ann Arbor Classification. However, when using TNM system, 7 were locally advanced T3, T4 lesions. All patients had follow up from 3.7 to 16 years with the median follow-up of 8.5 years. The overall actuarial 5-year survival rates were $25\%,\;28\%$ for IE and $0\%$ for IIE. Total tumor dose varied from 40 to 68 Gy. $100\%$ complete response with a total tumor dose of more than 55 Gy and $73\%$ complete response with less than 55Gy. When the disease was staged using the TNM (AJC) system, the five-year disease free survival for T1 and T2 patients was $50\%$ as compared with $14\%$ for T3 and T4. Failure rate by stage was $33\%(2/6)$ for T1 and T2, $86\%(6/7)$ for T3 and T4, and $100\%$(2/2) for IIE. The results suggest that 1. Higher CR could be obtained with a total tuner dose of more than 55 Gy. 2. Use of TNM staging system is as important as Ann arbor in management of sinonasal NHL. 3. The addition of combination chemotherapy should be considered for T3, T4 and IIE the sinonasal Non-Hodgkin's lymphoma although the disease is limited to head and neck.

• Radiation Oncology Journal
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• v.17 no.3
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• pp.217-222
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• 1999

Purpose : To evaluate prognostic factors and survival rates of the patients who received radiation therapy for locally recurrent uterine cervical cancer after curative surgery. Materials and Methods : Between October 1983 and July 1990, fifty three patients who received radiation therapy for locally recurrent cervical cancer after curative surgery at the Department of Therapeutic Radiology, Kangnam St. Mary's Hospital, The Catholic University of Korea were analysed retrospectively. Age at diagnosis ranged from 33 to 69 years (median 53 years). Pathological analysis showed that forty five ($84.9\%$) patients had squamous cell carcinoma, seven ($13.2\%$) patients had adenocarcinoma, and one (1.9%) patient had adenosquamous cell carcinoma. The interval between hysterectomy and tumor recurrence ranged from 2 months to 25 years (mean 34.4 months). The recurrent sites were vaginal stump in 41 patients ($77.4\%$) and pelvic side wall in 12 patients ($22.6\%$). Recurrent tumor size was devided into two groups : less than 3 cm in 43 patients ($81.1\%$) and more than 3 cm in 10 patients ($18.9\%$). External beam irradiation of whole pelvis was done first up to 46.8 Gy to 50.4 Gy in 5 weeks to 6 weeks, followed by either external beam boost to the recurrent site in 18 patients ($34\%$) or intracavitary irradiation in 24 patients ($45.3\%$). Total dose of radiation ranged from 46.8 Gy to 111 Gy (median 70.2 Gy). Follow up period ranged from 2 to 153 months with a median of 35 months. Results : Overall response rate was $66\%$ (35/53). Among them, six patients ($17.1\%$) relapsed between 7 months and 116 months after radiation therapy (mean 47.7 months), Therefore overall recurrence rate was $45.3\%$. Overall five-year actuarial survival rate was $78.9\%$ and distant failure rate was $10\%$ (5/50). The significant prognostic factors affecting survival rate were interval between primary surgery and tumor recurrence (p=0.0055), recurrent tumor size (p=0.0039), and initial response to radiation therapy (p=0.0428). Complications were observed in 10 ($20/%$) patients, which included mild to moderate lower gastrointestinal, genitourinary, or skin manifestations. One patient died of pulmonary embolism just after intracavitary irradiation. Conclustion : Radiation therapy is the effective treatment for the patients with locally recurrent cervical cancer after curative surgery. These results suggest that interval between primary surgery and tumor recurrence, recurrent tumor size, and initial response to radiation therapy were significant prognostic factors for recurrent cervical cancer.

• Radiation Oncology Journal
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• v.18 no.3
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• pp.182-186
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• 2000

Purpose : To determine treatment or이ecol for inoperable esophageal cancer patients, 껜e evaluated survival rate and prognostic factors. Materials and Methods : We evaluated esophageal cancer treated by curative or palliative am in KCCH from 1992 to 1996, retrospectively. Recurrent or underdose case below 40 Gy were excluded. The number of male and female were 35 and 5, respectively. Thirty-eight patients were squamous carcinoma and 2 patients were not biopsy proven. Ten patients were treated with radiation therapy and chemotherapy Median dose of radiation therapy was 59.4 Gy and the range was $40\~60$ Gy. Results : The median survival is 6.5 months and 1-year survival rate was $28.3\%$. Age, location, radiation dose and chemotherapy were not significant prognostic factors. Median survivals of patients with below stage III and over stage IVA were 7.6 and 6.2 months respectively, but it is not significant. Conclusions : The survival for esophageal cancer is very poor. For patients with curative aim, chemotherapy must be considered. For patients with palliative aim, short-term external beam radiation therapy and/or brachytherapy must be considered.

• Radiation Oncology Journal
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• v.25 no.3
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• pp.177-184
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• 2007

Purpose: To evaluate the palliative effect of endobronchial brachytherapy (EBB) for patients with lung cancer that previously received external beam radiotherapy (EBRT). Materials and Methods: From July 1992 to May 2003, 29 patients with a recurrent or persistent lung cancer were treated with palliative EBB at our institute. EBB consisted of three fractions (once a week) of a dose of 5 Gy using the high dose-rate remote afterloader. Symptomatic improvement was assessed subjectively, and patients were divided into two groups according to whether symptoms were improved or not. Factors such as age, performance status, duration from EBRT to EBB and the location of the tumor were compared between the improved and unimproved groups of patients. Results: Overall symptomatic improvement was found in 27 out of 52 symptoms (52%). Improvement as to the type of symptoms was seen in 41 %, 50%, 82% and 33% of patients with cough, dyspnea, hemoptysis, and obstructive pneumonia respectively. The rate of improvement of hemoptysis was more than that of cough (p<0.05). The median time to symptom relapse was 5 months. The improved patient group (n=17, 59%) had a better performance status and longer duration from EBRT to EBB than the unimproved patient group (p<0.05). Lesions located in the distal trachea and/or main bronchus were found more frequently in the improved group of patients than in the unimproved group of patients, but the difference was not statistically significant (p=0.06). Fatal complications developed in two patients (7%), which were a hemoptysis and bronchopleural fistula respectively. Conclusion: Symptom improvement was found in 60% of patients after EBB and improvement was maintained for 5 months. Palliative EBB, even when EBRT was given previously, can be effective for a patient that has an endobronchial symptom, such as hemoptysis, and for a patient with good performance and a long duration from previous EBRT to EBB.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.357-367
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• 1997

Purpose : To identify variable prognostic factors and analyse failure patterns in the uterine cervix cancer after radical operation and adjuvant radio-therapy, a retrospective analysis was undertaken. Materals and Methods : I analysed one hundred and twenty four patients with uterine cervix cancer, FIGO stage IB, IIA and IIB, treated with radical hysterectomy and pelvic lymph node dissection followed by adjuvant radio-therapy between May 1985 and May 1994. Minimum follow up period was 24 months. All of them were treated with full dose external radiotherapy with linear accelerator and/or high dese rate intracavitary radiation. Results : Overall 5 year survival rate and relapse free survival rate were $75.4\%,\;73.5\%$, respectively. Significant prognostic factors by relapse free survival were wall involvement thickness, lymph node location and number, parametrium involvement, tumor size, stage, uterine body involvement, vaginal resection margin involvement. By multivariate analysis, lymph node matastasis. tumor size and vaginal resection margin involvement were significant prognostic factos. Treatment related failure were 33 cases. Locoregional failure were more likely in the stage IIB, lymph node positive or vaginal resection margin positive patients whereas distant failures were relatively more frequent in stage IB, IIA and lymph node, vaginal resection negative patients. In stage IIB, 5 year relapse free survival rate was only $56\%$ and nine of twenty two patients recurred. Conculsion : Postoperative radiotherapy results are good for patients with relatively low risk factor. But the results are poor for patients with multiple, high risk factors or stage IIB. To control recurrence for patients with high risk factors, postoperative adjuvant radiotherapy is not sufficient treatment method. To raise control rate adding other methods such as radiosensitizing agent or chemotherapy is necessary and prospectively randomized study is needed for evaluation of postoperative radiotherapy efficacy and /or other methods. And it is reasonable to treat primary radical radiotherapy for patients with stage IIB cervical cancer instead of radical operation and adjuvant radiotherapy and/or chemotherapy regimen.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.109-116
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• 2015

Purpose: To analyze prognostic factors for locoregional recurrence (LRR), distant metastasis (DM), and overall survival (OS) in cervical cancer patients who underwent radical hysterectomy followed by postoperative radiotherapy (PORT) in a single institute. Materials and Methods: Clinicopathologic data of 135 patients with clinical stage IA2 to IIA2 cervical cancer treated with PORT from 2001 to 2012 were reviewed, retrospectively. Postoperative parametrial resection margin (PRM) and vaginal resection margin (VRM) were investigated separately. The median treatment dosage of external beam radiotherapy (EBRT) to the whole pelvis was 50.4 Gy in 1.8 Gy/fraction. High-dose-rate vaginal brachytherapy after EBRT was given to patients with positive or close VRMs. Concurrent platinum-based chemoradiotherapy (CCRT) was administered to 73 patients with positive resection margin, lymph node (LN) metastasis, or direct extension of parametrium. Kaplan-Meier method and log-rank test were used for analyzing LRR, DM, and OS; Cox regression was applied to analyze prognostic factors. Results: The 5-year disease-free survival was 79% and 5-year OS was 91%. In univariate analysis, positive or close PRM, LN metastasis, direct extension of parametrium, lymphovascular invasion, histology of adenocarcinoma, and chemotherapy were related with more DM and poor OS. In multivariate analysis, PRM and LN metastasis remained independent prognostic factors for OS. Conclusion: PORT after radical hysterectomy in uterine cervical cancer showed excellent OS in this study. Positive or close PRM after radical hysterectomy in uterine cervical cancer correlates with poor prognosis even with CCRT. Therefore, additional treatments to improve local control such as radiation boosting need to be considered.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.168-173
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• 2015

The present investigation was planned to estimate potential possibility of striped field mice, Apodemus agrarius coreae (A. a. coreae), as a biological dosimeter in radio-environmental ecology. We bred captured wild A. a. coreae at laboratory and classified taxonomically based on external, cranial and tooth characters. Organ weights and splenocytic apoptosis were observed in order to establish a basic data on radiation biology of A. a. coreae (male, 40 weeks old). The biological effects was observed at 24hrs following irradiation (doses : 0, 0.5, 1, 2 Gy, dose rate : $0.8Gymin^{-1}$, $^{137}Cs$). Only thymus weights was significantly decreased. Splenocytic apoptosis was increased after irradiation. But splenocytic apoptosis was decreased in 0.5 Gy ${\gamma}$-irradiated mice compared to those of 0, 1, 2 Gy (P < 0.05). These data suggested that events in thymus and spleen of Korean dark-striped field mice, A. a. coreae THOMAS, could be a potential radio-biological indicator in human environments.