• Radiation Oncology Journal
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• 제33권3호
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• pp.233-241
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• 2015

Purpose: To compare volumetric modulated arc therapy of RapidArc with robotic stereotactic body radiation therapy (SBRT) of CyberKnife in the planning and delivery of SBRT for hepatocellular carcinoma (HCC) treatment by analyzing dosimetric parameters. Materials and Methods: Two radiation treatment plans were generated for 29 HCC patients, one using Eclipse for the RapidArc plan and the other using Multiplan for the CyberKnife plan. The prescription dose was 60 Gy in 3 fractions. The dosimetric parameters of planning target volume (PTV) coverage and normal tissue sparing in the RapidArc and the CyberKnife plans were analyzed. Results: The conformity index was $1.05{\pm}0.02$ for the CyberKnife plan, and $1.13{\pm}0.10$ for the RapidArc plan. The homogeneity index was $1.23{\pm}0.01$ for the CyberKnife plan, and $1.10{\pm}0.03$ for the RapidArc plan. For the normal liver, there were significant differences between the two plans in the low-dose regions of $V_1$ and $V_3$. The normalized volumes of $V_{60}$ for the normal liver in the RapidArc plan were drastically increased when the mean dose of the PTVs in RapidArc plan is equivalent to the mean dose of the PTVs in the CyberKnife plan. Conclusion: CyberKnife plans show greater dose conformity, especially in small-sized tumors, while RapidArc plans show good dosimetric distribution of low dose sparing in the normal liver and body.

• 대한한방내과학회지
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• 제39권4호
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• pp.676-685
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• 2018

Objectives: The aim of this study was to estimate the single oral toxicity of Peucedani Radix (PR) ethanol extracts. PR is one of the important herbs for removal of phlegm, the viscous turbid pathological product that can accumulate in the body and cause a variety of diseases. However, research on the pharmacologic toxicity of PR is lacking. Methods: In this study, PR was orally administered to 5-week-old male ICR mice at an oral dose of 2,000, 3,000, or 5,000 mg/kg. After a single-dose administration, the mortality and behavioral changes were observed daily and body weights were measured every two days. After 14 days, the organ weight, organ index, macroscopy, hematological analysis, and serum biochemistry analysis were determined. Results: No mortality, body weight changes, abnormal behavioral changes, or anatomical signs of toxicity were found. The organ weight, organ index, hematological analysis, and serum biochemistry analysis were also within the normal ranges. Conclusions: These results suggest that the 50% lethal dose of PR is more than 5,000 mg/kg. This could indicate that PR is a safe drug without acute toxicity and side effects.

• Journal of Radiation Protection and Research
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• 제11권1호
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• pp.37-43
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• 1986

ICRU 구(球)를 피사체(被射體)로 하여 300 keV 중성자(中性子)의 방사선량(放射線量) 관계량(關係量)을 평가(評價)하였다. 피사체내(被射體內)의 선량당량(線量當量) 분포(分布)를 직접(直接) 산정(算定)하기 위해 중성자(中性子)-광자(光子)-하전입자(荷電粒子) 결합수송(結合輸送)을 다룰 수 있는 몬테칼로 코드 NEDEP을 사용하였다. 계산결과(計算結果) 얻은 방사선량(放射線量) 관계량(關係量)은 다음과 같다. 심부선량당량지수(深部線量當量指數) $H_{I,d}:1.78{\times}10^{11}\;Sv-cm^2$ 표층선량당량지수(表層線量當量指數) $H_{I,s}:2.08{\times}10^{-1}\;Sv-cm^2$ 주위선량당량(周圍線量當量) $H^*(0.07):1.70{\times}10^{-11}\;Sv-cm^2$ 주위선량당량(周圍線量當量) $H^*(10):1.78{\times}10^{-11}\;Sv-cm^2$ 실효선질계수(實效線質係數) $\bar{Q}^*(10):12.4$

• Journal of Radiation Protection and Research
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• 제33권1호
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• pp.41-46
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• 2008

[ $^{99m}Tc$ ]를 주사할 때 시술자의 손가락에 흡수되는 방사선량을 예측하기 위해, GEANT4를 이용하여 초당 370 MBq의 방사능량을 가지는 0.4 mL 체적의 $^{99m}Tc$ 선원을 대상으로 각 손가락에 대한 등가선량을 구하였다. 시뮬레이션 결과, 오른손 엄지($0.29\;{\mu}Sv{\cdot}sec^{-1}$), 검지($1.19\;{\mu}Sv{\cdot}sec^{-1}$), 중지($1.07\;{\mu}Sv{\cdot}sec^{-1}$), 왼손 엄지($4.36\;{\mu}Sv{\cdot}sec^{-1}$), 검지($3.37\;{\mu}Sv{\cdot}sec^{-1}$)의 등가선량을 얻을 수 있었다. 이와 같은 계산 결과는 $^{99m}$Tc 주입시 시술자의 손가락에 흡수되는 선량을 예측할 수 있는 유용한 기초자료로 활용될 수 있을 것이다.

• 한국의학물리학회지:의학물리
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• 제34권4호
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• pp.48-54
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• 2023

Purpose: In this study, the dosimetric characteristics of lung stereotactic body radiotherapy (SBRT) plans using the new Halcyon system were analyzed to assess its suitability. Methods: We compared the key dosimetric parameters calculated for the Halcyon SBRT plans with those of a conventional C-arm linear accelerator (LINAC) equipped with a high-definition multileaf collimator (HD-MLC)-Trilogy Tx. A total of 10 patients with non-small-cell lung cancer were selected, and all SBRT plans were generated using the RapidArc technique. Results: Trilogy Tx exhibited significant superiority over Halcyon in terms of target dose coverage (conformity index, homogeneity index, D_{0.1 cc}, and D_95%) and dose spillage (gradient). Trilogy Tx was more efficient than Halcyon in the lung SBRT beam delivery process in terms of the total number of monitor units, modulation factor, and beam-on time. However, it was feasible to achieve a dose distribution that met SBRT plan requirements using Halcyon, with no significant differences in satisfying organs at risk dose constraints between both plans. Conclusions: Results confirm that Halcyon is a viable alternative for performing lung SBRT in the absence of a LINAC equipped with HD-MLC. However, extra consideration should be taken in determining whether to use Halcyon when the planning target volume setting is enormous, as in the case of significant tumor motions.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.101-104
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• 2016

Background: To protect the public from natural radioactive materials, the 'Act on safety control of radioactive rays around living environment" was established in Korea. There is an annual effective dose limit of 1 mSv for products, but the activity concentration limit for products is not established yet. Materials and Methods: To suggest the activity concentration limits for consumer goods containing NORM, in this research, we assumed the "small room model" surrounding the ICRP reference phantom to simulate the consumer goods in contact with the human bodies. Using the Monte Carlo code MCNPX, we evaluate the effective dose rate for the ICRP reference phantom in a small room with dimension of phantom size and derived the activity concentration limit for consumer goods. Results and Discussion: The consumer goods have about 1600, 1200 and $19000Bq{\cdot}kg^{-1}$ for $^{226}Ra$, $^{232}Th$ and $^{40}K$, and the activity concentration limits are about six times comparing with the values of building materials. We applied the index to real samples, though we did not consider radioactivity of $^{40}K$, indexes of the some samples are more than 6. However, this index concept using small room model is very conservative, for the consumer goods over than index 6, it is necessary to reevaluate the absorbed dose considering real usage scenario and material characteristics. Conclusion: In this research, we derived activity concentration limits for consumer goods in contact with bodies and the results can be used as preliminary screening tool for consumer goods as index concept.

• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.533-538
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• 2018

As the use of digital radiographic system has been expanded, there are some concerns an increase about in patient of radiation dose. Therefore, International Electro-technical Commission (IEC) has been proposed a standard foe exposure index (EI). In this study, the EI was measured on human chest model using computed radiography (CR). Radiation quality used RQA5 of IEC62494-1. After acquiring the chest anterior posterior image (Chest AP) by using the phantom, the EI was obtained by applying the system response. In this study, we have analyzed the images with the detector size (Full filed ROI) and the optimized image (Fit filed ROI). The EI increased proportionally with radiation dose increase. Due to the discrete increase in pixel value, the EI showed an exponential increase. The discrete increase in noise equivalent quanta (NEQ) resulted in a discrete increase in the EI. The EI of the two images used in this study increased with increasing NEQ but showed different increments. For the measurement of the EI, IEC standards must be followed. The EI should be used as an index to evaluate the image quality for quality control of X-ray image rather than as an indicator of exposure dose. When calculating the EI, the system response should be applied depending on whether or not the grid is used. The size of the field should be obtained by including only the necessary parts.

• 대한방사선치료학회지
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• 제23권2호
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• pp.91-96
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• 2011

목 적: 전신조사방사선치료를 시행한 환자에서 체질량지수와 열형광선량계를 이용한 선량측정 정보를 비교 분석하여 환자에게 보다 균등한 선량을 조사하고자 한다. 대상 및 방법: 2006년부터 2011년 8월까지 전신조사방사선치료를 시행한 환자 28명을 대상으로 하였다. 각 환자는 열형광선량계를 이용하여 두부, 경부, 흉부, 복부, 골반부, 대퇴부, 슬관절부, 족관절부에서 선량을 측정하였다. 각각의 환자에 대하여 처방 중심점인 복부점과 각 측정점에서의 선량측정치를 비교하였고, 선량기준이 되는 복부점의 측정값과 환자의 체질량지수를 비교 분석하였다. 결 과: 28명 환자에서 처방에 기준이 되는 중심점인 복부선량은 평균 $100.6{\pm}5.5%$이었고, 복부점과 다른 7개의 측정점 평균값과의 최대 차이는 두부, 경부, 흉부, 골반부, 대퇴부, 슬관절부, 족관절부에서 각각 $92.8{\pm}4.2%$, $97.6{\pm}6.2%$, $96.4{\pm}5.5%$, $102.6{\pm}5.3%$, $103.4{\pm}7.9%$, $95.8{\pm}5.9%$, $96.1{\pm}5.5%$였다. 각각의 환자에 대하여 복부점의 선량과 환자의 체질량지수와 관계를 산점도(scatter plot)로 나타내고 선형관계를 회귀분석 한 결과, 회귀직선은 선량(y)=-1.009 BMI (x)＋123.3이고 $R^2$값은 0.697로 나타났다. 결 론: 전신방사선치료시 열형광선량계로 측정된 자료를 바탕으로 선량을 평가하였고 분석 결과 처방 선량에 대하여 기준이 되는 복부선량은 평균 $100.6%{\pm}5.5%$로 만족하였다. 본 실험결과 체질량지수와 선량과의 관계 분석을 통하여 얻은 정보에 따라 체질량지수가 높은 환자에 대하여 보정 값을 적용한다면 보다 균등한 선량을 달성할 수 있을 것으로 사료된다.

• 한국방사선학회논문지
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• 제10권3호
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• pp.161-169
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• 2016

본 연구에서는 소아 두부 CT 검사에 있어서 피폭 방사선량을 경감할 수 있는 방법을 모색하고자 부산지역 병원들에서 시행된 년 간 소아 두부 CT 검사에 대한 CT 선량지표(CTDI)를 국내 진단참고준위와 비교하여 분석함으로써 제안점을 도출하고자 하였다. 결과적으로 병원별 분류에서는 병원, 종합병원, 상급종합병원 순으로 권고량이 초과하는 것으로 나타났으며 연령별 분류에서는 2-5세 이하, 1개월-1세 이하, 6-10세 이하 순으로 권고량이 초과하는 것으로 나타났다. 스캔방식별 분류에서는 Helical, Axial, Volume방식 순으로 권고량이 초과하고 있었으며 스캔범위를 진단참고준위에 맞게 재설정한 결과 상급종합병원에서 재설정으로 인한 감소율은 11.68%, 종합병원에서 15.79%, 병원에서 20.66%로 초과율이 높게 나타났다. 그리고 환자선량 권고량 가이드라인을 벗어나지 않는 환자의 평균 스캔범위의 분석결과 1개월-1세 이하에서 $103.2{\pm}11.8mm$, 2-5세 이하에서 $110.5{\pm}14.5mm$, 6-10세 이하에서는 $117.8{\pm}17.2mm$로 나타났다.

• 한국의학물리학회지:의학물리
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• 제12권2호
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• pp.171-175
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• 2001

본 연구에서는 고정틀 정위방사선치료장비에 사용되는 치료계획시스템과 무고정틀 정위방사선치료시스템에 사용되는 치료계획시스템을 이용하여 intracranial 표적을 대상으로 치료계획을 수립하였다. 치료계획을 평가하기 위하여 RTOG-9005 규정서에서 정위방사선치료계획의 정도관리를 위하여 사용한 Planning Target Volume Coverage를 확인하고 Conformity Index(CI)와 Homogeneity Index(HI)를 구하였다. 이들 값으로부터 두 치료계획시스템에서 계산한 치료계획이 동일함을 알 수 있었다.