• Radiation Oncology Journal
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• v.17 no.4
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• pp.269-274
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• 1999

Purpose : To evaluate the Possibility of decreasing the radiation dose and to determine optimum treatment volume in intracranial germinomas. Materials and Methods : Forty five patients with pathologically-verified or presumed germinomas by a radiosensitivity test who had been treated with radiotherapy (RT) alone between 1971 and 1992 were retrospectively analyzed. The average age was 17.2 years with 68.9$\%$ of the patients being between the ages of 10$\~$20. The male and female ratio was 2.2:1. The locations of the primary tumors were at the pineal regions in 14 patients; the suprasellar regions in 12 patients; and multiple sites in 12 patients. Treatment volumes varied from a small local field (10) to the whole brain (7) or entire neuroaxis irradiation(28). All the cases after 1982 received craniospinal irradiation (CSI). Radiation doses were 41-59 Gy (median 48.5 Gy) to the primary tumor site and 19.5$\~$36 Gy (median 24 Gy) to the neuroaxis. The median follow-up period was 82 months with a range of 2$\~$260 months. Results : All the patients showed complete response after RT. Four patients sufferred from recurrence 14, 65, 76, and 170 months after RT, respectively, and two patients died with intercurrent disease. One of four recurrent cases was salvaged by re-irradiation. Therefore, a 5 and 10 year overall suNival was 95.3$\%$ and 84.7 $\%$ respectively. Five and ten year disease-free survival was 97.6 $\%$ and 88.8 $\%$ respectively. All the recurrences occurred in the patients who received local RT (3/10) or whole brain RT (1/7) with a radiation dose of 48-50 Gy. None of the patients who received CSI suffered recurrence. There was no recurrence among the 15 patients who received $\leq$45 Gy to the primary site and the 18 patients who received $\leq$24 Gy (6 patients received 19.5 Gy) to the neuroaxis. Conclusion : CSI is recommended for the treatment of intracranial germinomas. The radiation dose can be safely decreased to $\leq$45 Gy on a primay tumor site and 19.5 Gy on the spine.

• Radiation Oncology Journal
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• v.21 no.4
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• pp.283-290
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• 2003

Purpose: To evaluate the long term significance of the squamous cell carcinoma (SCC) antigen (Ag) as a tumor marker in uterine cervix carcinoma. Materials and Methods: The SCC antigen levels of pre-radiotherapy and serial post-radiotherapy serum were analyzed in 48 patients who received radiotherapy with histologically proven primary SCC of the uterine cervix. Results: Pre-radiotherapy SCC Ag level was high ($\geq$2 ng/ml) at 79.2$\%$. After the treatment, the SCC Ag level was significantly decreased. The SCC Ag level measured at about 3 months after radiotherapy was high at 23.0$\%$. In further follow up measurements, a rise of the SCC Ag to a high level was well associated with clinical relapse. The specificity of the elevated SCC Ag level in association with recurrent or persistent disease was 100$\%$, and the sensitivity was 85.7$\%$. In 3 of 4 lung metastasis cases, lung lesions were detected in chest PA before elevation of the SCC Ag level. The median lead time of the high SCC Ag level to clinical recurrence was 4 months. Conclusion: SCC Ag was a good tumor marker for monitoring treatment effect in patients with increased pre-treatment levels except in case of early lung metastasis. Elevation of the SCC Ag level after radiotherapy accurately predicted the treatment failure with lead time of 4 months. But, in early lung metastasis cases, the SCC level may be normal temporarily. Thus, chest PA should be checked to evaluate the presence of lung metastasis.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.255-262
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• 1997

Purpose : This is retrospective study to compare the results of radiation therapy alone and neoadjuvant chemotherapy and radiation in advanced stage of uterine cervical cancer. Materials and Methods : Seventy-six Patients who were treated with definitive radiation therapy for locally advanced cervical cacinoma between June 1988 and December 1993 at the department of radiation oncology, Keimyung University Dong-san Hospital. Thirty six patients were treated with radiation therapy alone and forty patients were treated with cisplatin based neoadjuvant chemotherapy and radiation therapy. According to FIGO staging system. there were 48 patients in stage IIb, 3 patients in stage IIIa, 23 patients in stage lIIb and two patients in stage IVa with median age of 53 years old. Follow-up periods ranged from 7 to 95 months with median 58 months. Results : Complete response (CR) rate were $86.1\%$ in radiation alone group and $80\%$ in chemoradiation group. There was no statistical difference in CR rate between the two groups. Overall five-year survival rate was $67.3\%$. According to stage, overall five-rear survival rates were $74\%$ in stage IIb, $66.7\%$ in stage IIIa, $49.8\%$ in stage IIb, $50\%$ in stage IVa. According to treatment modality overall five year survival rates were $74.1\%$ in radiation alone and $61.4\%$ in chemoradiation group (P=0.4) Five rear local failure free survival rates were $71.5\%$ in radiation alone group and $60\%$ in chemoradiation group (P=0.17). Five year distant metastasis free survival rates were $80.7\%$ in radiation aione group and $89.9\%$ in chemoradiation group (P=0.42). Bone marrow suppression (more than noted in 3 cases of radiaion alone group and 1 case of chemoradiation group. Grade II retal complication was noted in 5 patients of radiation group and 4 patients In chemoradiation group. Bowel obstruction treated with conservative treatment (1 patient) and bowel perforation treated with surgery (1 patient) were noted in radiation alone group. There was no statistical difference in complication between two groups. Conclusion : There was no statistical difference in survival, failure and complication between neoadjuvant chemotherapy and radiation versus radiation alone in locally advanced uterine cervical carcinoma.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.299-306
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• 1996

Purpose : Respiratory symptoms related with malignant airway disease have been the main causes of lowered qualify of life and also sometimes may be life-threatening if not properly managed. The authors report the short-term experiences of endobronchial brachytherapy for symptomatic malignant airway obstruction using high dose rate after-loading brachytherapy unit. Materials and Methdos : Twenty-five Patients with symptomatic malignant airway obstruction were treated with endobronchial brachytherapy between the period of December 1994 and March 1996 at Department of Radiation Oncology of Samsung Medical Center Twenty-one ($84\%$) were patients with non-small cell lung cancer, three with tracheal malignancies, and one with recurrence of esophageal cancer. Twenty Patients were given elective external beam radiation therapy, while six were given endobronchial laser evaporation therapy on emergency bases in addition to endobronchial brachytherapy. Three procedures for each patient were planned and total of 70 procedures were completed. Results : Improvement rates of major respiratory symptoms after endobronchial brachytherapy procedures were $88\%$(22/25). $96\%$(22/23), $100\%$ (15/15), and $100\%$(9/9) for cough, dyspnea, hemoptysis and obstructive pneumonia, respectively. ECOG performance scores were improved in $56\%$ of total patients group, while there was no case with worsened ECOG score. Fifteen patients died and the median interval from the start of treatment to death was 4 months (range: $1\~17$ months), while that of ten survivors was 9 months (range $5\~19$ months). There were five patients with controlled intrathoracic disease, who have survived over one rear. All deaths were associated with uncontrolled local and/or distant disease. Four Patients died of massive fatal hemoptysis, three of who received emergency endobronchial laser evaporation therapy before the start of endobronchial brachytherapy. Conclusion : Endobronchial brachytherapy has been confirmed as an excellent palliative treatment modality improving respiratory symptoms as well as patients' general performance status. Based on the current observations, use of endobronchial brachytherapy in curative setting as a boost technique may be warranted.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.105-111
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• 1997

group($22\%\;vs.\;38\%$, p=0.24). The 5YSRs of 21 patients of primary tumor extension to adjacent sites and the other 13 patients of tonsillar proper site were $28\%\;and\;38\%$, respectively but the difference was not significant statistically(p=0.52) There was a statistically significant difference in 5YSRs between the groups of the Patients who received radiotherapy in less than 61days vs more than 60days($60\%\;vs.\;18\%$, p=0.027). All living Patients without any tumor progression(n=11) had suffered from serious late sequelae such as xerostomia, edentia, dental caries and one patient had the osteoradionecrosis of mandible. On univariate analysis. the duration of radiotherapy and T-stage were the significant prognostic factors affecting 5YSR. On multivariate analysis, also the duration of radiotherapy was the only significant Prognostic factor(p=0.01). Conclusion : There was no survival difference between the radiotherapy alone and with neoadiuvant chemothe groups. Although it was a retrospective study, the role of conventional radiotherapy alone could be effective as the local treatment modality only for the early stage of tonsillar carcinomas. But for the purpose of more improved survivals and better quality of lives of living patients, other altered fractionation such as hyperfractionated radiotherapy with shorter treatment time and smaller fraction size rather than conventional radiotherapy might be beneficial and these prospective studies are needed.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.11-16
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• 2000

Purpose :We peformed the retrospective analysis to find the outcome of external beam radiotherapy alone in advanced esophageal cancer patients. Methods and Materials : One hundred and six Patients treated with external beam radiotherapy alone between July 1990 and December 1996 were analyzed retrospectively. We limited the site of the lesions to the thoracic esophagus and cell type to the squamous cell carcinoma. Follow-up was completed in 100 patients (94$\%$) and ranged from 1 month to 92 months (median; 6 months). Results :The median age was 62 years old and male to female ratio was 104 2. Fifty-three percent was the middle thorax lesion and curative radiotherapy was peformed in 83$\%$. Mean tumor dose delivered with curative aim was 58.6 Gy (55$\~$70.8 Gy) and median duration of the radiation therapy was 53 days. The median survival of all patients was 6 months and )-year and 2-year overall survival rate was 27$\%$ and 12$\%$, respectively, Improvement of dysphagia was obtained in most patients except for 7 patients who underwent feeding gastrostomy. The complete response rate immediately after radiation therapy was 32$\%$ (34/106). The median survival and 2-year survival rate of the complete responder was 14 months and 30$\%$ respectively, while those of the nonresponder was 4 months and 0$\%$ respectively (p=0.000). The median survival and 2-year survival rate of the patients who could tolerate regular diet was 9 months and 16$\%$ while those of the patients who could not tolerate regular diet was 3 months and 0$\%$, respectively (p=0.004). The survival difference between the patients with S cm or less tumor length and those with more than 5 cm tumor length was marginally statistically significant (u=0,06). However, the survival difference according to the periesophageal invasion or mediastinal tyrnphadenopathy in the chest CT imaging study was not statistically significant in this study. In a multivariate analysis, the statistically significant covariates to the survival were complete response to radiotherapy, tumor length, and initial degree of dysphagia in a decreasing order. The complication was observed in 10 patients (9$\%$). Conclusion :The survival outcome for advanced esophageal cancer patients treated by external beam radiotherapy alone was very poor. In the treatment of these patients, the brachytherapy and chemotherapy should be added to improve the treatment outcome.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.219-226
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• 2007

Purpose: The aim of this retrospective analysis was to analyze the results of radiotherapy administered to patients with neck node metastases from an unknown primary cancer, with or without neck dissection. Materials and Methods: From January 1986 to December 2005, 88 patients with neck node metastases from an unknown primary cancer were treated with curative intent. The age of the patients ranged from 35 to 74 years (median age, 59 years). There were 74 male and 14 female patients. Distribution of patients by N status was as follows: N1, 4 patients; N2a, 10 patients; N2b, 48 patients; N2c, 8 patients; N3, 18 patients. Fifty-one patients underwent neck dissection and 37 patients had only a biopsy (31 patients had fine-needle aspiration and 6 patients had an excisional biopsy). All patients received radiotherapy. The follow-up time ranged from 1 to 154 months, with a median time of 32 months. Results: The overall survival (OS) and disease-free survival (DFS) rate at 5 years were 43.9% and 41.7%, respectively. The factors associated with the OS rate were neck dissection, and a subsequent primary tumor. Factors associated with the DFS rate were N stage, neck dissection, and a subsequent primary tumor. Neck failure was noted in 15 patients, distant metastases in 18 patients, and a subsequent primary tumor in 8 patients. Conclusion: With comprehensive radiotherapy given to the bilateral neck and the potential mucosal sites, good survival rates can be obtained in patients with neck node metastases from an unknown primary cancer. However, considering the side effects, a randomized trial is required to determine the optimal radiotherapy volume.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.185-194
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• 1998

Purpose : With the development of stereotactic immobilization systems capable of reliable serial repositioning, fractionated stereotactic radiation therapy (FSRT) offers the Potential for an improved treatment outcome by excellent dose delivery, and dose distribution characteristics with the favorable radiobiological properties of fractionated irradiation. We describe our initial experience using FSRT for the treatment of intracranial benign tumor. Materials and Methods : Between August 1995 and December 1996. 15 patients(7 males and 8 females aged 6-70 years) were treated with FSRT. The patients had the following diagnosis pituitary adenoma(10) including one patient who previously had received radiotherapy, craniopharyngioma (2), acoustic neurinoma (1), meningioma (2). Using the Gill-Thomas-Cosman relocatable head frame and multiple non-coplanar therapy, the daily dose of 2Gy was irradiated at 90% to 100% isodose surface of the isocenter The collimator sizes ranged from 26mm to 70mm. Results : In all patients except one follow-up lost, disease was well-controlled. Acute complication was negligible and no patient experienced cranial nerve neuropathies and radiation necrosis. In overall patient setup with scalp measurements, reproducibility was found to have mean of $1.1{\pm}0.6mm$ from the baseline reading. Conclusion : Relocatable stereotactic system for FSRT is highly reproducible and comfortable. Although the follow-up period was relatively short. FSRT is considered to be a safe and effective radiation technique as the treatment of intracranial tumor. But the fractionation schedule(fraction size, overall treatment time and total dose) still remains to be solved by further clinical trials.

• Radiation Oncology Journal
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• v.26 no.2
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• pp.113-117
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• 2008

Purpose: To evaluate the long term results(local control, survival, failure, and complications) after radiation therapy for skin cancer in elderly patients. Material and Methods: The study spanned from January 1990 to October 2002. Fifteen elderly patients with skin cancer were treated by radiotherapy at the Keimyung University Dongsan Medical Center. The age distribution of the patients surveyed was 72 to 95 years, with a median age of 78.8 years. The pathologic classification of the 15 patients included squamous cell carcinoma(10 patients), basal cell carcinoma(3 patients), verrucous carcinoma(1 patient) and skin adnexal origin carcinoma(1 patient). The most common tumor location was the head(13 patients). The mean tumor diameter was 4.9 cm(range 2 to 9 cm). The radiation dose was delivered via an electron beam of 6 to 15 MeV. The dose range was adjusted to the tumor diameter and depth of tumor invasion. The total radiation dose ranged from $50{\sim}80$ Gy(mean: 66 Gy) with a 2 Gy fractional dose prescribed to the 80% isodose line once a day and 5 times a week. One patient with lymph node metastasis was treated with six MV photon beams boosted with electron beams. The length of the follow-up periods ranged from 10 to 120 months with a median follow-up period of 48 months. Results: The local control rates were 100%(15/15). In addition, the five year disease free survival rate(5YDFS) was 80% and twelve patients(80%) had no recurrence and skin cancer recurrence occurred in 3 patients(20%). Three patients have lived an average of 90 months($68{\sim}120$ months) without recurrence or metastasis. A total of 9 patients who died as a result of other causes had a mean survival time of 55.8 months after radiation therapy. No severe acute or chronic complications were observed after radiation therapy. Only minor complications including radiation dermatitis was treated with supportive care. Conclusion: The results suggest that radiation therapy is an effective and safe treatment method for the treatment of skin cancer in elderly patients who achieved a good survival rate and few minor complications.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.05a
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• pp.35-81
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• 1998

Distinct Element Method(DEM) has a great advantage to model the discontinuous behaviour of jointed rock masses such as rotation, sliding, and separation of rock blocks. Geometrical data of joints by a field monitoring is not enough to model the jointed rock mass though the results of DE analysis for the jointed rock mass is most sensitive to the distributional properties of joints. Also, it is important to use a properly joint law in evaluating the stability of a jointed rock mass because the joint is considered as the contact between blocks in DEM. In this study, a stochastic modelling technique is developed and the dilatant rock joint is numerically modelled in order to consider th geometrical and mechanical properties of joints in DE analysis. The stochastic modelling technique provides a assemblage of rock blocks by reproducing the joint distribution from insufficient joint data. Numerical Modelling of joint dilatancy in a edge-edge contact of DEM enable to consider not only mechanical properties but also various boundary conditions of joint. Preprocess Procedure for a stochastic DE model is composed of a statistical process of raw data of joints, a joint generation, and a block boundary generation. This stochastic DE model is used to analyze the effect of deviations of geometrical joint parameters on .the behaviour of jointed rock masses. This modelling method may be one tool for the consistency of DE analysis because it keeps the objectivity of the numerical model. In the joint constitutive law with a dilatancy, the normal and shear behaviour of a joint are fully coupled due to dilatation. It is easy to quantify the input Parameters used in the joint law from laboratory tests. The boundary effect on the behaviour of a joint is verified from shear tests under CNL and CNS using the numerical model of a single joint. The numerical model developed is applied to jointed rock masses to evaluate the effect of joint dilation on tunnel stability.