• 한국의학물리학회지:의학물리
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• 제28권3호
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• pp.111-121
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• 2017

Verification of dose distribution is an essential part of ensuring the treatment planning system's (TPS) calculated dose will achieve the desired outcome in radiation therapy. Each measurement have uncertainty associated with it. It is desirable to reduce the measurement uncertainty. A best approach is to reduce the uncertainty associated with each step of the process to keep the total uncertainty under acceptable limits. Point dose patient specific quality assurance (QA) is recommended by American Association of Medical Physicists (AAPM) and European Society for Radiotherapy and Oncology (ESTRO) for all the complex radiation therapy treatment techniques. Relative and absolute point dose measurement methods are used to verify the TPS computed dose. Relative and absolute point dose measurement techniques have a number of steps to measure the point dose which includes chamber cross calibration, electrometer reading, chamber calibration coefficient, beam quality correction factor, reference conditions, influences quantities, machine stability, nominal calibration factor (for relative method) and absolute dose calibration of machine. Keeping these parameters in mind, the estimated relative percentage uncertainty associated with the absolute point dose measurement is 2.1% (k=1). On the other hand, the relative percentage uncertainty associated with the relative point dose verification method is estimated to 1.0% (k=1). To compare both point dose measurement methods, 13 head and neck (H&N) IMRT patients were selected. A point dose for each patient was measured with both methods. The average percentage difference between TPS computed dose and measured absolute relative point dose was 1.4% and 1% respectively. The results of this comparative study show that while choosing the relative or absolute point dose measurement technique, both techniques can produce similar results for H&N IMRT treatment plans. There is no statistically significant difference between both point dose verification methods based upon the t-test for comparing two means.

• 대한방사선기술학회지:방사선기술과학
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• 제31권1호
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• pp.89-95
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• 2008

국제원자력기구의 TRS-398 측정 프로토콜을 임상에 적용하기 위해서는 사용하는 빔과 전리함에 대한 선질 보정인자가 필요하다. 본 연구에서는 몬테칼로 계산코드(DOSRZnrc/EGSnrc)를 사용하여 상용의 평판형전리함에 대한 고에너지 전자선($4{\sim}20\;MeV$)에서의 선질보정인자를 계산하였다. 계산결과를 프로토콜에서 제시하는 값과 비교한 결과 $5{\sim}20\;MeV$에서 약 1% 이내로 일치하였으며 4 MeV의 경우에는 약 1.9% 차이를 보였다. 본 연구 방법은 선질보정인자를 독립적으로 결정하는 방법의 하나로서 프로토콜에서 주어진 값들의 확인이 필요하거나 또는 새로운 모델의 전리함을 사용하는 경우에 응용될 수 있다.

• 한국의학물리학회지:의학물리
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• 제26권4호
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• pp.241-249
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• 2015

방사선치료는 수술, 항암치료와 함께 암의 3대 치료방법으로써 많은 암환자들이 방사선치료를 받게 된다. 최대한 많은 방사선을 암에 집중시키고 최대한 적은 방사선을 주변 정상 조직에 가해주기 위해 치료 전 치료계획을 철저히 세우고 품질 관리를 시행하지만 방사선치료가 잘못 시행되어 의도치 않은 방사선이 환자에게 전달되는 의료사고가 발생하기도 한다. 이를 해결하기 위해 환자 내부의 선량을 검증하기 위한 방법을 투과선량 측정을 통한 환자 내부선량의 역추정 방법이 제시되고 있다. 본 연구에서 제시한 투과선량을 이용한 환자선량 계산 방법을 거리역자승법칙, 심부선량백분율, scatter factor를 이용한 방법으로써 실제 환자 선량 평가 가능성에 대해 균질한 물등가 팬텀을 이용한 연구이다. 투과선량에 대한 이온함과 유리선량계의 교정 결과 유리선량계의 신호값이 이온함으로 측정한 선량값에 비해 6 MV에서 0.824, 10 MV에서 0.736배인 것으로 나타났고 scatter factor는 평균적으로 1.4정도인 것으로 확인되었다. 심부선량백분율 데이터를 사용하기 위해 Mayneord F factor를 적용하였으며 위의 정보들을 이용하여 균질한 팬텀에서 알고리즘을 검증한 결과 최대 오차 약 1.65%로 계산이 정확하게 실시됨을 확인하였다.

• Radiation Oncology Journal
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• 제9권2호
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• pp.361-367
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• 1991

This paper on the status of radiotherapy machine and related facilities, clinical activities and radiation safety management is based on the statistical data which collected through the questionaire sent to a total number of 37 hospitals holding the Department of Therapeutic Radiology in Korea. It is true that the quality of instruments installed in the hospitals equal to that of the instrument in the industrialized conuntries' hospitals. But the clinical specialists and physicists who can utilize such instruments fall short of the required number, which might be a main factor in hindering the development of therapeutic radiology of Korea. According to the nation-wide cancer statistics, we can estimate the number of annual cancer patients as 45,000 to 50,000. As a result, probably around 25,000 should receive radiation therapy. It is expected that in the future the number of cancer patients to whom radiation therapy should be applied will become twice as much as that of the cancer patients in 1990. Given such a condition, the problem facing the Korean Society of Therapeutic Radiology now is to increase the number of medical doctors and physicists.

• 대한방사선치료학회지
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• 제14권1호
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• pp.187-199
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• 2002

This descriptive study was undertaken to measure quality of life score and investigate the correlation between the demographic characteristics, the diagnostic related characteristics, physical symptom and quality of life of breast cancer patients undergoing radiation therapy as on attempt to provide basic data to help them attain better qualify of life. The subjects for this study were 74 out-patients undergoing radiation therapy at C University hospital in Gwangju, from June, 1998 to July, 2000. The data were obtained using a convenient sampling technique. The tool of this study was the quality of life scale developed by Ro Yoo Ja. The data were analyzed using the SAS program for percentage, mean, standard deviation, Pearson Correlation Coefficient, GLM. The results were as follows: 1. The total average score for quality of life of the subjects was 137.22 and the range was from 38 to 227, item mean score(range 1-5) was 3.15. For each factor in qualify of life of life score, the mean scores(range 1-5) were as follows; family relationship 3.69, relationship with neighbors factor 3.40, self esteem 3.10, physical state and function 2.95, economic life 2.91, emotional fate 2.88. 2. The incidence of physical symptoms was seen fatigue($82.4\%$), skin change($43.2\%$), alopecia($41.9\%$), pain($41.9\%$), anorexia($39.2\%$), anemia($39.2\%$), and headache($31.1\%$) in that order. 3. The result of the analysis of the relationships between the quality of life scores and demogaphic characteristics were as follows : there were significant differences, between age(F=3.44, p=0.013), educational level(F=3.84, p=0.007), duration of marriage((F=5.06, p=0.003) and monthly income(F=4.72, p=0.005). 4. The result of the analysis of the relationships between quality of life scores and diagnostic related characteristics was as follows: there was a significant difference between incidence durations(F=5.02, p=0.003). 5. The correlation of emotional state, economic life, self esteem, physical sate & function, relationship with neighbors, relationship with family in quality of life of cancer patients revealed a positive correlation.

• 대한전자공학회논문지TC
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• 제45권8호
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• pp.1-7
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• 2008

본 논문에서는 손실을 고려한 Metamaterial(MTM) 전송선의 단일 셀을 구성하고, 이 전송선에서 방사효과를 갖는 파라미터들의 실제 값을 구해본다. 그리고 이 단일 셀을 이용하여 분산 다이어그램을 그려, 여러 셀을 cascade로 연결하여 공진체로 사용하기 위한 조건들을 찾아낸다. 공진체로 사용할 시 종단을 단락 또는 개방을 하게 되는데, 각각의 경우에 따라 공진 주파수를 알아내기 위해 나타나는 입력 임피던스 혹은 입력 어드미턴스에 대해서 논의한다. 이를 이용하여 공진 체의 Quality Factor와 대역폭을 구하였으며, 공진 안테나의 입력 어드미턴스를 회로 시뮬레이션과 EM 시뮬레이션에서 비교하였다. 또한 단일 셀을 이용한 안테나를 설계하여, $0.05\lambda_0\times0.12\lambda_0$의 초소형 안테나로의 설계 시 방사효과 모델링이 어떤 영향을 미치는지 분석하였다.

• 대한방사선치료학회지
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• 제6권1호
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• pp.154-170
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• 1994

The Purpose of this study was to determine the degree and contents composing the qualify of life and to analyze the relationships among the demographic characteristics, the degree of pain and the quality of life of the cancer patients experiencing a radiation therapy. The subjects for this study were 110 out-patients experiencing a radation therapy at C University Hospital in K-city, from April to October, 1992. The data were obtained using a convenience sampling technique. The tool of this study was the quality of life scale developed by Ro, You-Ja and the data were analyzed using a SAS program for percentages, mean & standard deviation. ANOVA and Scheffe test. The results were as follows : 1. the average total score of the quality of life of the subjects was 139.65(minimum score 121-maximum score 164), item mean score grange 1-5) was 2.97. For each factor in the quality of life scale, the mean scores (range 1-5) were 3.29 in emotional state, 3.14 in relationship with neighbors. 3.04 in physical state and function. 2.92 in self-esteem, 2.81 in economic life and 2.65 in relationship with family. 2. The incidence of physical symptoms was seen fatigue ($84.5\%$). anorexia ($65.5\%$) and weight loss ($47.3\%$) in order. The 50.9 percentage of the subjects complained of moderate or severe pain. 3. The results of the analysis of the relationships between the demographic variables and the quality of life were as follows : Gender (F=8.45, P=0.0044), age (F=6.29, P=0.0001). educational level (F=5.67, P=0.0046), marital status (F=6.82. P=0.0016), occupation (F=2.86, P=0.009), monthly income (F=6.90, P=0.0003), family living together (F=3.95, P=0.0494) and person paying a medical fee (F=5.14, P=0.0023). 4. The relationship between the degree of pain and the quality of life was significant difference (F=3.12, P=0.0482).

• 한국의학물리학회지:의학물리
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• 제21권1호
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• pp.120-125
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• 2010

물흡수선량에 기반한 표준 측정법을 사용하여 흡수선량을 측정 시에 여러 요인들이 크건, 작건, 미미하건 간에 선량 측정의 정확성에 영향을 미칠 수 있다. 이온함의 선질 보정 인자(the beam quality correction factor) ${\kappa}_{Q,Q_0}$ 값 또한 그 중 한 요인이 될 수 있다. 본 연구에서는 특정 이온함 유형(PTW30013, PTW, Germany)을 선정하여, 국내에서 사용하고 있는 기관들로부터 9개의 이온함을 수집하였다. 동일한 전위계와 전기선으로 9개 이온함을 국내 이차표준기관으로부터 교정을 받았다. 이렇게 교정받은 이온함들을 사용하여 Siemens ONCOR 장비의 광자 빔 6 MV와 10 MV 그리고 전자 빔 12 MeV에 대해 기준 조건하에서 흡수선량을 측정하였다. 이온함 간 선량 값의 최대 차이는 광자 빔 6 MV의 경우엔 2.4%, 10MV의 경우에 0.8%, 전자 빔 12 MeV의 경우엔 0.8%이었다. 6 MV에서의 큰 차이는 측정 과정에 문제가 없었다면, 동일한 ${\kappa}_{Q,Q_0}$ 값을 모든 이온함에 적용한 게 한 요인이 될 수 있다. 이는 또한 외부 독립검사가 왜 중요한지를 보여 주는 예라 하겠다.

• Journal of Radiation Protection and Research
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• 제35권3호
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• pp.91-95
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• 2010

The study aimed to measure the levels of radiation protection for radiologists in medical institutions in three environmental categories (physical, administrative and social) and to establish a data base which can be used to increase awareness of environmental radiation protection in medical institutions within Korea. The study surveyed 10% of radiologists working in radiology departments in medical institutions which are supervised by the National Dose Registry overseen by the Korean Food and Drug Administration(KFDA). This study found that the level of environmental radiation protection was higher in the capital area and in larger hospitals. On the other hand, the study shows environmental radiation protection was lower in the Youngnam area and in clinics. Results from the questionnaires indicate the level of environmental radiation protection was higher when radiologists were given an individual dosimeter but lowest when the radiation protection apron quality test was conducted. Environmental radiation protection is an important factor for radiologists to conduct activities in a safe and protected environment. However, this study shows there are differences in the level of environmental radiation protection in medical institutions and location within Korea. In particular, the level of environmental radiation protection was lower in clinics, appropriate intervention strategies befitting these conditions are needed based on medical institution classification and location in order to improve the level of environmental protection.

• 한국산학기술학회논문지
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• 제17권11호
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• pp.663-669
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• 2016

본 논문에서는 높은 감도의 테라헤르츠 센서로 응용이 가능한 고품질 비대칭 분리고리공진기(ASLR: Asymmetric Split-Loop Resonator) 메타물질의 구조적인 비대칭 정도에 따른 ASLR의 공진특성 변화를 전자기 시뮬레이션을 통하여 분석하였다. 특히, ASLR의 구조적 비대칭성은 높은 품질인자를 갖는 파노공진을 발생시키므로 ASLR의 비대칭성 정도에 따라서 ASLR 고유공진과 파노공진의 공진주파수 변화와 투과계수 및 품질인자의 변화를 분석하였다. 또한, ASLR의 구조적 비대칭성에 따른 ASLR의 공진 특성 변화의 원인을 분석하기 위해 표면전류밀도를 계산하여 ASLR 공진의 공진주파수, 투과계수, 그리고 품질인자가 변화하는 이유를 분석하였다. 이를 통하여 ASLR 고유공진의 표면전류밀도는 이중 극자를 형성하여 높은 방사 손실을 가지게 되므로 품질인자가 낮아지게 되고, 파노공진의 표면전류밀도는 닫힌 모드 또는 사중 극자를 형성하여 이중 극자에 비하여 낮은 방사 손실을 가지므로 파노공진 상태의 ASLR이 높은 품질인자를 가지게 됨을 확인하였다. 이러한 ASLR의 파노공진 특성 분석 결과를 바탕으로 메타물질의 비대칭성을 조절하면 높은 품질인자를 가지는 테라헤르츠 고성능 필터 또는 고감도 센서 개발이 가능하다. 이러한 고감도 고성능 테라헤르츠 소자 개발은 테라헤르츠 메타물질의 실질적인 산업 응용을 유도할 것으로 기대한다.