• Radiation Oncology Journal
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• 제23권2호
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• pp.85-91
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• 2005

Purpose : This study was conducted to analyze treatment outcome and prognostic significance of World Health Organization (WHO)-defined thymic epithelial tumor (TET) subtype and to assess optimal radiation target volume in patients receiving surgery and adjuvant radiation therapy with TET. Materials and Methods: The record of 160 patients with TET, who received surgical resection at the Samsung medical Center, from December 1994 to June 2004, were reviewed. 99 patients were treated with postoperative radiation therapy (PORT). PORT was recommended when patients had more than one findings among suspicious Incomplete resection or positive resection margin or Wasaoka stage $II\~IV$ or WHO type $B2\~C$. PORT peformed to primary tumor bed only with a mean dose of 54 Gy. The prognostic factor and pattern of failure were analyzed retrospectively. Results : The overall survival rate at 5 years was $87.3\%$. Age (more than 60 years $77.8\%$, less than 60 years $91.1\%$; p=0.03), Wasaoka stage (I $92.2\%$, II $95.4\%$, III $82.1\%$, IV $57.5\%$; p=0.001), WHO tumor type (A-Bl $96.0\%$, B2-C $82.3\%$; p=0.001), Extent of resection (R0 resection $92.3\%$, R1 or 2 resection $72.6\%$, p=0.001) were the prognostic factors according to univariate analysis. But WHO tumor type was the only significant prognostic factor according to multivariate analysis. Recurrence was observed in 5 patients of 71 Masoka stage I-III patients who received grossly complete tumor removal (R0, R1 resection) and PORT to primary tumor bed. Mediastinal recurrence was observed In only one patients. There were no recurrence within irradiation field. Conclusion : WHO tumor type was the important prognostic factor to predict survival of patients with TET. This study suggest that PORT to only primary tumor bed was optimal. To avoid pleura- or pericardium-based recurrence, further study of effective chemotherapy should be investigated.

• Applied Biological Chemistry
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• 제12권
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• pp.83-88
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• 1969

In order to inhibit sprouting of garlics during the storage period and the extend their storage life, garlics were irradiated by gamma-rays $(Co^{60})$ and kept at room temperature. The effects of gammaradiation on sprouting inhibition, chemical contents during storage, and spoilage molds were investigated and the results are as follows. 1. Garlics obtained from Muan showed the shorter dormancy period and sprouted earlier than those from Dangjin. 2. Regarding the radioresistance, some differences were found between garlics from Muan and Dangjin. 3. The sprout of garlics from both areas was completely inhibited at 10 Krad and remarkable effect on sprouting was observed even with 5 Krad in case of garlics from Dangjin. 4. The rates of loss in moisture and weight were lower in irradiated lots than control. 5. Change of sugar content was not observed with ${\gamma}-irradiation$ under 300 Krad. 6. Spores of Aspergillus niger and Aspergillus alliaceus were little germinated at a level of 300 Krad.

• Radiation Oncology Journal
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• 제28권1호
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• pp.1-8
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• 2010

Purpose: This retrospective study was performed to evaluate the efficacy of radiation therapy (RT) and to investigate the prognostic factors for thymoma when treated with RT. Materials and Methods: We analyzed 21 patients with thymoma and also received RT from March 2002 to January 2008. The median follow-up time was 37 months (range, 3 to 89 months). The median patient age was 57 years (range, 24 to 77 years) and the gender ratio of males to females was 4：3. Of the 21 patients, complete resections (trans-sternal thymectomy) and R2 resections were performed in 14 and 1 patient, respectively. A biopsy was performed in 6 patients (28.7%). The WHO cell types in the 21 patients were as follows: 1 patient (4.8%) had type A, 10 patients (47.6%) had type B1-3, and 10 patients (47.6%) had type C. Based on Masaoka staging, 10 patients (47.6%) were stage II, 7 patients (33.3%) were stage III, and 4 patients (19.1%) were stage IVa. Three-dimensional RT was adminstered to the tumor volume (planned target volume), including the anterior mediastinum and the residual disease. The total RT dose ranged from 52.0 to 70.2 Gy (median dose, 54 Gy). Consistent with the WHO criteria, the response rate was only analyzed for the 6 patients who received a biopsy only. The prognostic factors analyzed for an estimate of survival included age, gender, tumor size, tumor pathology, Masaoka stage, the possibility of treatment by performing surgery, the presence of myasthenia gravis, and RT dose. Results: The 3-year overall survival rate (OS) and the progression free survival rate (PFS) were 80.7% and 78.2%, respectively. Among the 10 patients with WHO cell type C, 3 of 4 patients (75%) who underwent a complete resection and 3 of 6 patients (50%) who underwent a biopsy survived. Distant metastasis developed in 4 patients (19.1%). The overall response rate in the 6 patients who received biopsy only were as follows: partial remission in 4 patients (66.7%), stable disease in 1 patient (16.6%), and progressive disease in 1 patient (16.6%). Acute RTOG radiation pneumonitis occurred in 1 patient (4.8%), grade 2 occurred in 2 patients (9.5%), grade 3 occurred in 1 patient (4.8%), and grade 4 occurred in 1 patient (4.8%). A univariate analysis revealed that the significant prognostic factors for OS were age (${\geq}60$, 58.3%; <60, 100%; p=0.0194), pathology (WHO cell type A-B3, 100%; C, 58.3%; p=0.0194) and, whether the patient underwent surgery (yes, 93.3%; no, 50%; p=0.0096). Conclusion: For the 15 patients who received surgery, there was no local failure within the radiation field. In patients with WHO cell type C, surgical procedures could have resulted in a more favorable outcome than biopsy alone. We report here our clinical experience in 21 patients with thymoma who were treated by radiation therapy.

• Radiation Oncology Journal
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• 제29권1호
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• pp.11-19
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• 2011

Purpose: To evaluate the pathological and clinical effects of preoperative chemoradiation (CCRT) in cases of locally advanced rectal cancer and to determine the predictive factors for tumor downstaging. Materials and Methods: From March 2004 to August 2008, 33 patients with locally advanced rectal cancer were treated with preoperative CCRT. Twenty-eight patients (84.8%) were treated using a concomitant boost technique while five (15.2%) patients were treated using a cone down boost technique. All patients received 50.4 Gy of irradiation and concurrent chemotherapy with 5-fluorouracil. The median follow-up duration was 24.2 months (range, 9.8 to 64.7 months). Results: Thirty-one (93.9%) patients underwent surgery. Twenty-four patients (72.7%) underwent anal sphincter-preserving surgery. The 3-year disease free survival (DFS) and overall survival rates were 63.4% and 78.8%, respectively. Post-operative factors were more important for DFS. Pathologic N stage, margin status, and pathologic differentiation were significant prognostic factors (p=0.001, 0.029, 0.030). Tumor size and lymphovascular invasion were also associated with marginal significance (p=0.081, 0.073). However, only pre-treatment T stage was a significant pre-operative factor (p=0.018). The complete pathological response rate was 9.1 %. T-downstaging was observed in ten (30.3%) patients, whereas N-downstaging was found in 24 (72.7%) patients. Pre-treatment T stage and the interval between CCRT and operation were the predictive factors for downstaging in a univariate analysis (p=0.029, 0.027). Pre-treatment carcinoembryogenic antigen was also associated with marginal significance (p=0.068). Conclusion: The survival of rectal cancer patients can be better determined based on post-operative findings. Therefore, pre-operative CCRT for downstaging of the tumor seems to be important. Pre-treatment T stage and the interval between CCRT and operation can be used to predict downstaging.

• Radiation Oncology Journal
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• 제15권3호
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• pp.233-241
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• 1997

Purpose : This study was done to evaluate the survival rate and Prognostic factors of patients with inoperable non-small cell lung cancer(NSCLC) treated with radiation therapy. Materials and Methods A retrospective analysis was undertaken of 62 Patients who had inoperable NSCLC treated with radiation therapy from January 1991 through December 1993. According to AJCC slaging, stage IIIA was 14 patients and stage IIIB was 48 patients. Forty Gy to 70.2Gy to the primary tumor site was delivered with daily fractions of 1.8Gy or 2Gy, 5days per week. Thirty-seven patients received neoadjuvant chemotherapy. Results : Complete, partial and no response to radiation therapy were 3 patients, 34 Patients and 25 patients, respectively The median survival period of all patients was 11 month. One rear survival rate, 2 year survival rateand 5 rear survival rate for all patients were 45.0%, 14.3%, and 6.0% respectively The median survival period was 6.5 months in stage IIIA and 13 months in stage IIIB. One year survival rates were 28.6% in stage IIIA and 50.3% in stage IIIB In univariaite analysis, prognostic factors affecting survival were T-s1aging, AJCC staging, and response after radiation therapy (P<0.05) . Pretreatment peformance status affected survival but was not statistically significant (0.050.1). In multivariate analysis, Pathology and response to radiation therapy are independently significant prognostic factor. T stage was marginally significant (P=0.0809). During follow-up duration, distant metastasis developed in 20 patients-bone metastasis in 10 patients, brain metastasis in 3 patients, liver mentastasis in 3 patients, contralateral lung metastasis in 1 patients and multiple metastases in 3 patients. Conclusion :　Conventional radiotherapy alone or combined chemoradiotherapy are unlikely to achieve long term survival in patients with NSCLC.　Surgery after concurrent chemoradiotherapy is Ivied to improve the local　control in our hospital

• Radiation Oncology Journal
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• 제25권2호
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• pp.118-124
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• 2007

[ $\underline{Purpose}$ ]: This study was to evaluate the survival and pattern of failure after radiation therapy of sino-nasal cancer using partial attenuation filer and wedged beams and to help radiotherapy planning of sino-nasal cancer. $\underline{Materials\;and\;Methods}$: Between February 1992 and March 2003, 17 patients with sino-nasal cancers underwent radiation therapy using partial attenuation filter at Dongsan Medical Center, Keimyung university. There were 9 male and 8 female patients. Patients' age ranged from 40 to 75 years (median 59 years). There were 10 patients of maxillary sinus cancer, 7 patiens of nasal cancer. The histologic type was squamous cell carcinoma in 11, adenoid cystic carcinoma in 4 and olfactory neuroblastoma in 2. The distribution of clinical stage by the AJCC system was 3 for stage II, 7 for III and 6 for IV. The five patients were treated with radiation alone and 12 patients were treated with surgery and postoperative radiation therapy. The range of total radiation dose delivered to the primary tumor was from 44 to 76 Gy (median 60 Gy). The follow-up period ranged from 3 to 173 months with median of 78 months. $\underline{Results}$: The overall 2 year survival rate and disease free survival rate was 76.4%. The 5 year and 10 year survival rate were 76.4% and 45.6% and the 5 year and 10 year disease free survival rate was 70.6%. The 5 year disease free survival rate by treatment modality was 91.6% for postoperative radiation group and 20% for radiation alone group, statistical significance was found by treatment modality (p=0.006). There were no differences in survival by pathology and stage. There were local failure in 5 patients (29%) but no distant failure and no severe complication required surgical intervention. $\underline{Conclusion}$: Radiation therapy of sino-nasal cancer using partial attenuation filter was safe and effective. Combined modality with conservative surgery and radiation therapy was more advisable to achieve loco-regional control in sino-nasal cancer. Also we considered high precision radiation therapy with dose escalation and development of multi-modality treatment to improve local control and survival rate in advanced sino-nasal cancer.

• Radiation Oncology Journal
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• 제12권3호
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• pp.393-399
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• 1994

Spinal cord compression, an oncologic emergency, is a rare complication of hematologic malignancy Our experience was obtained with a series 32 Patients following retrospective analysis for assessing the role of radiation therapy and identifying the prognostic factors affecting on treatment outcome. Diagnosis was usually made by means of radiologic study such as myelography or computerized tomography (CT) or magnetic resonance imaging (MRI) and neurologic examination. Five cases were diagnosed by subjective symptom only with high index of suspicion. In 31 cases, the treatment consisted in radiation therapy alone and the remained one patient had laminectomy before radiation therapy because of diagnostic doubts. Total treatment doses ranged from 800 cGy to 4000 cGy with median of 2000 cGy. Initially large fraction size more than 250 cGy were used in 13 patients with rapidly progressed neurologic deficit. The clinical parameters considered in evaluating the response to treatment were backache, motor-sensory performance and sphincter function. Half of all patients showed good response. Partial response and no response were noted in $37.5\%$ and $12.5\%$, respectively. Our results showed higher response rate than those of other solid tumor series. The degree of neurologic deficit at that time of diagnosis was the most important predictor of treatment outcome. The elapsed time from development of symptoms to start of treatment was significantly affected on the outcome. But histology of primary tumor total dose and use of initial large fraction size were not significantly affect on the outcome. These results confirmed the value of early diagnosis and treatment especially in radiosensitive hematologic malignancy.

• Journal of the Korean Society for Nondestructive Testing
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• 제16권1호
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• pp.19-28
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• 1996

This study has investigated the optimization of NDT method and the minimum detectable defect size for complex structures such as the solid propellant rocket motor using real time X-ray imaging system. Test specimens were made of steel plates with various defect size, and installed with proper thickness for which solid propellant, rubber, and case converted to the steel equivalent thickness according to the radiographic equivalent theory. As the results, this examination obtained optimum magnification and X-ray energy, dose rate according to steel equivalent thickness, also, obtained the relationship between minimum detectable defect size and the ratio(defect depot/object thickness). Thus, this simulated test is the preliminary procedure before performing NDT for real objects, and is possibly applied for NDT of other complex structures.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제16권10호
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• pp.2329-2334
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• 2012

In this paper, we performed a study of damage assessment model development to analyze the initial nuclear pulse radiation damage to semiconductor devices for military weapon systems. At first we modeled(M) the nuclear pulse radiation and diode device, and simulated(S) the output characteristics of the device to the input. Then the manufactured diodes which had the same characteristics with the modeled one were irradiated to the similar pulsed type radiation and their output signals were measured simultaneously. Error between the M & S results and the measured values of the analysis was 22.9%. Through the error value we could confirm that the damage assessment model simulated the TREE effects with a quite accuracy.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.397.1-397.1
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• 2014

최근 방사선 진단 영역에 이용되고 있는 증감지는 입사된 방사선의 감도를 증가시키기 위해 형광체를 사용하고 있으며, 외부의 에너지를 흡수하여 빛으로 방출하는 역할을 한다. 이는 방사선 검출기, 디스플레이, 의료기기 등 다양한 분야에 활용되고 있다. 필름에 X선을 노출 할 경우 형광체의 사용 유무에 따라 방사선 흡수 효율에 영향을 미치며, 이는 발광 효율 및 감도에 주요한 인자로 작용한다. 현재 상용화되어 있는 형광체는 낮은 발광 효율로 인한 한계를 가지므로, 발광 효율 향상을 위하여 제작 구조에 대한 연구가 진행되고 있다. 이 중 반사막을 활용하는 연구가 활발히 진행되고 있다. 일반적으로 형광체의 제조를 위하여 보편적으로 이용하고 있는 스크린프린팅 방법에서 건조 공정을 수행 시 균일도가 감소하는 현상이 발생한다. 이러한 현상은 반사막의 증착을 불균일하게 만드는 원인으로 작용하고 빛의 산란을 초래하는 현상을 초래한다. 이에 본 연구에서는 증착 시 투명도 저하에 따라 반사율이 증가되는 반사막 성질을 가지며, 방수성 및 절연성과 같은 보호층 특성을 지닌 유기성 투명 박막 페를린에 대하여 연구하고자 한다. 본 연구에서는 화학적 증기 증착법(Chemical Vapor Deposition, CVD)을 이용하여 투명 필름의 상단에 페를린을 코팅한 시편과 코팅하지 않은 시편으로 구분하여 제작하였고, 상단에 스크핀프린팅 방법을 활용하여 형광체를 도포 하였다. 시편 제작 후 실험은 시편을 필름 상단에 위치시키고, 일반진단에너지 대역(Model-SF 80)의 X선을 조사하였다. 이 후 현상기(model-pro14)를 통해 현상된 필름에 나타난 광학적 농도(Optical Density, O.D)를 농도계(Fluke Biomedical Nuclear Associates Densitometer)로 측정하였는데, 불확실성을 줄이기 위하여 총 5회를 측정하여 그 중 2번째로 높은 값을 도출하였다. 측정 결과, 페를린을 코팅한 형광체에서는 1.71의 O.D 값이 측정되었고, 페를린을 코팅하지 않은 형광체에서는 1.43의 O.D 값이 측정되었다. 이를 이용하여 투명도를 산출한 결과 상대적으로 약 1.76% 차이가 나타났다. 이러한 결과는 페를린 활용 시 환자의 피폭 선량 저감화 및 해상력 개선을 도모할 수 있을 것으로 사료된다.