폐액중 금속 성분의 생물학적 제거 : 광합성 세균 ( Rhodospirilum rubrum ) 에 의한 우라늄 흡착

박효국,김진규,김인규,이강석 한국하천호수학회 1990 생태와 환경 Vol.23 No.4

스트론튬-90 자동 분리기와 기체비례계수기를 이용한 우유 분말 중의 방사성 스트론튬 분석

박효국,정근호,권용대,박두원,최상도,조영현,이완로,김희령,이창우,강문자,최근식 대한방사선방어학회 2009 대한방사선방어학회 학술발표회 논문요약집 Vol.2009 No.11

영광 및 울진 원전 주변 논 토양으로부터 벼로의 년차별 90Sr 전이

박효국,이한수,임광묵,최용호,강희석,최희주 대한방사선방어학회 2003 방사선방어학회지 Vol.28 No.4

- 영광 및 울진 원전 반경 5 km 내 12 곳의 논토양 블록을 재배상자에 채취하여 벼의 이식 전과 출수 시작 1~2 일 전에 90Sr을 담수의 표면에 처리하였다. 이식 전 처리에 있어서는 전이계수를 2~4 년 간 조사하였다. 이식전 처리시 당년도 90Sr의 전이계수(m2 kg-1-dry plant)는 지역 간에 이렇다할 차이없이 토양에 따라 2 배 정도의 변이를 보였고 평균은 쌀알의 경우 2.6×10-4, 볏짚의 경우 1.3×10-2였다. 출수 전 처리시 전이계수는 이식전 처리에 비해 대체로 2 배 정도 높았다. 토양의 pH와 치환성 Ca 함량이 높을수록 90Sr 전이계수가 감소하는 경향이었다. 우리나라 논에 대하여 침적 당년도 90Sr 전이계수의 대표치가 제안되었다. 처리 1차 년도에 대한 2차 년도 전이계수의 감소 정도는 대체로 모래함량이 높은 울진 토양에서 영광 토양보다 높았다. 영광 토양 전체로 볼 때 년차에 따른 전이계수의 감소는 반감기가 2.2년 정도의 지수함수로 묘사될 수 있었다.

조직결손이 큰 환자에서 물 볼루스의 적용에 관한 고찰

박효국,이상규,윤종원,조정희,김동욱,김주호,Park, Hyo-Kuk,Lee, Sang-Kyu,Yoon, Jong-Won,Cho, Jeong-Hee,Kim, Dong-Wook,Kim, Joo-Ho 대한방사선치료학회 2006 대한방사선치료학회지 Vol.18 No.2

Purpose: To demonstrate that water bolus in the patient surface can decrease the dose inhomogeneity by patient surface large tissue defect when the surface is in an electron-beam field. And We tried to find a easy way to water control. Methods and Materials: To demonstrate the use of water bolus in the irregular surface clinically, the case of a patient with myxofibrosarcoma of the chest wall who was treated with electrons. We obtained dose distribution using missing tissue option of PINACLE 6.2b (ADAC, USA). We fabricate a Mev-green for water bolus in patient with defect of tissue. Then put the water bolus which is vinyl packed water into the designed Mev-green. We peformed CT scan with CT-simulator. Three-dimensional (3D) dose distributions with and without water bolus in the large irregular chest wall were calculated for a representative patient. Resulting dose distributions and dose-volume histograms of water bolus were compared with missing tissue option and non bolus plans. We fabricate a new water control device. Results: Controlled Water bolus markedly decrease the dose heterogeneity, and minimizes normal tissue exposure caused by the surface irregularities of the chest wall mass. In the test case, The non bolus plan has a maximum target dose of 132%. After applying water bolus, the maximum target dose has been reduced substantially to 110.4%. The maximum target dose was reduced by 21.6% using this technique. Conclusion: The results showed that controlled water bolus could significantly improve the dose homogeneity in the PTV for patients treated with electron therapy using water control device. This technique may reduce the incidence of normal organ complications that occur after electron-beam therapy in irregular surface. And our new device shows handiness of water control.

The Effectiveness of Volumetric Modulated arc Radiotherapy to Treat Patients with Metastatic Spinal Tumors

박효국,김성철 한국콘텐츠학회 2017 International Journal of Contents Vol.13 No.4

Among the possible stereotactic body radiation therapy (SBRT) modalities used to treat patients with metastatic spinal tumors, this study compared Cyberknife, tomotherapy, and volumetric modulated arc radiotherapy (VMAT). We established treatment plans for each of them modality and quantitatively analyzed the dose evaluation factors of the dose-volume histogram (DVH) for all spinal bones, focusing on the tumor and spinal cord, in order to examine the usefulness of VMAT. For the treatment planning dose, the mean dose (Dmax) and D5% showed statistical differences in the target dose, but no difference was shown in the spinal cord dose. For the DVH indices, tomotherapy showed the best performance was the best in terms of uniformity index, while VMAT showed better performance was better than the other two modalities in terms of the conformity index and the dose gradient index. VMAT had a much shorter treatment time than Cyberknife and tomotherapy. These findings suggest that VMAT FFF is the most effective therapy for SBRT of patients with metastatic spinal tumors for whom a high dose of radiation is prescribed.

137Cs Concentrations in Cultivated Soils of Korea

Park,Hyo-Guk,Lee,Myung-Ho,Choi,Yong-Ho,Lim,Kwang-Muk,Lee,Won-Yun 대한방사선 방어학회 1999 방사선방어학회지 Vol.24 No.2

우리 국토의 방사선환경을 이해하고 사고에 대비한 베이스라인 데이타를 축적하기 위하여 전국 33 지역의 논과 밭에서 15 cm 깊이로 토양을 채취하고 γ-스펙트로메트리법으로 Cs 농도를 측정하였다. 토양증 ??Cs의 농도는 논에서는 0.7∼17.7 ㏃/㎏-dry, 밭에서는 1.2∼27.8 ㏃/㎏-dry의 범위로 평균은 각각 6.9 ㏃/㎏-dry 및 9.9 ㏃/㎏-dry였다. 토양중 Cs의 농도는 논에서는 유기물 함량과 정의 상관이, 점토 함량과는 부의 상관이 있었고 밭에서는 양이온치환용량과 정의 상관이 있었다. 토양 유기물이 경작지 토양중 Cs의 농도변화에 중요한 역할을 하는 것으로 드러났다. For understanding the radiation environment in the land of Korea and acquiring baseline data to be referred to at the time of a nuclear accident, cultivated soils in the 0∼15 cm layer were sampled at 33 sites scattered all over the country and Cs concentrations were measured by γ-spectrometry. The soil Cs concentrations were in the range of 0.7∼17.7 ㏃/㎏-dry in the paddy field and 1.2∼27.8 ㏃/㎏ in the upland field. The means were 6.9 ㏃/㎏-dry and 9.9 ㏃/㎏-dry, respectively. In the paddy field, the soil ?/Cs concentration was positively correlated to the organic matter content and negatively correlated to the clay content. In the upland field, it was positively correlated to the cation exchange capacity. It was revealed that soil organic matter plays an important role in the change of soil Cs concentration.

Experimental Studies for Analyzing Direct Contamination Path way of 54Mn, 57Co, 85Sr, 123Rw and 134Cs in Rice

Lee,Won-Yun,Park,Hyo-Guk,Choi,Yong-Ho,Lim,Kwang-Muk,Lee,Chang-Min 대한방사선 방어학회 2000 방사선방어학회지 Vol.25 No.1

벼의 방사성 핵종 직접오염 경로를 분석하기 위하여 동위원소 실험온실내에서 ??Mn, ??Co, ??Sr, ??Ru, ??Cs의 혼합용액을 벼의 생육중 여섯 차례에 걸쳐 작물체 지상부에 처리하였다. 작물체차단계수는 핵종 간에 차이가 없었고 처리시기가 수확기에 가까울수록 증가하여 최고 약 0.94에 달하였다. 작물체에 침적한 각 핵종의 수확시 잔류율은 방사능 붕괴가 없다고 가정할 때 처리시기에 따라 각각 19∼47%, 17∼43%, 19∼42%, 23∼61%, 11∼69%였다. 종실전류계수는 처리시기에 따라 각각 6.9×10??∼3.8×10??, 3.6×10??∼1.6×10??, 5.8×10??∼3.2×10??, 1.6×10??∼7.6×10??, 3.2×10??∼2.0×10??의 범위였고 모두 종실의 발육성기 처리시 가장 높았다. 강우 빈도의 차이가 2배 이내일 때는 강우빈도가 잔류율과 전류계수에 큰 영향을 미치지 않는 것으로 나타났다. 본 연구결과는 벼의 생육중 사고침적시 쌀알 내 핵종농도 예측에 활용될 수 있다. For analyzing the direct contamination pathway of radionuclides in rice plants, a solution containing ??Mn, ??Co, ??Sr, ??Ru and ??Cs was applied to the aboveground parts of the rice plants in a greenhouse at 6 different times during their growth. The plant interception factor showed little difference among radionuclides and increased with decreasing time intervals between RI application and harvest. Its highest observed value was 0.94. The fractions of the initial plant deposition that remanined in rice plants at harvest were in the range of 19∼47%, 17∼43%, 19∼42%, 23∼61% and 11∼69% for ??Mn, ??Co, ??Sr, ??Ru and ??Cs, respectively, when no decay was assumed. The translocation factors of those radionuclides in hulled seeds were in the range of 6.9×10??∼3.8×10??, 3.6×10??∼1.6×10??, 5.8×10??∼3.2×10??, 1.6×10??∼7.6×10?? and 3.2×10??∼2.0×10??, respectively, and were highest when they were applied at the stage of active seed development. it was indicated that the remaining percentage and translocation factor would not be greatly affected by the difference in the rain frequency if it is within a factor of 2. These results can be utilized for predicting the radionuclied concentrations in rice seeds when an accidental deposition of those radionuclides occurs during the rice-growing season.

Yonsei Cancer Center QA Set을 이용한 6DoF Couch의 이동 정확성 검증

정동민,박효국,윤종원,이상규,김주호,조정희,Jung, Dongmin,Park, Hyokuk,Yoon, Jongwon,Lee, Sangkyu,Kim, Jooho,Cho, Jeonghee 대한방사선치료학회 2017 대한방사선치료학회지 Vol.29 No.1

목 적: 영상유도를 통한 6DoF Couch의 이동 정확성의 검증을 위해 QA Set을 제작하였고, 그 유용성을 평가하였다. 대상 및 방법: 6DoF Couch와 CBCT가 설치된 두 대의 선형가속기를 대상으로 하였으며, 자체 제작한 YCC QA Set을 이용하여 수평수직(Translation; TX, TY, TZ)과 회전(Rotation, Pitch; RX, Roll; RY, Yaw; RZ) 여섯방향의 Off-Set 값이 설정된 Penta-Guide Phantom의 CBCT영상을 각각 15회에 걸쳐 획득하였다. 이를 통해 기준영상(Reference Image)과 보정영상(Registration Image)을 비교하였으며, 보정된 6DoF Couch의 이동정확성을 실측하여 오차를 분석하였다. 결 과: 기준영상과 보정영상의 Air Cavity에 해당하는 Pixel들은 모두 30에서 66 사이에 포함되어 보정정확도가 높게 나타났다. 6DoF Couch의 Off-set의 보정 결과 값과 실측치의 비교에서 수평수직방향의 오차는 TX방향은 $0.25{\pm}.18mm$ TY방향은 $0.25{\pm}.25mm$ TZ방향에서 $0.36{\pm}.2mm$로 나타났다. 그리고 회전방향의 오차는 RX방향은 $0.18{\pm}.08^{\circ}$ RY방향은 $0.26{\pm}.09^{\circ}$ RZ방향에서 $0.11{\pm}.08^{\circ}$로서, 임의의 값에 대하여 정확하게 보정되었다. 결 론: YCC QA Set을 이용해 매우 간단한 방법으로 6DoF Couch의 수평수직방향뿐 아니라 회전방향의 오차에 대한 검증을 할 수 있었으며, 이는 6DoF Couch의 Daily IGRT QA를 수행함에 있어서 유용할 것이라 사료된다. Purpose: A QA Set was established to verify the movement accuracy of image-guided 6DoF Couch and to evaluate its usefulness. Materials and Methods: Two sets of linear accelerators equipped with 6DoF Couch and CBCT were used. Using the established QA Set, each CBCT image was obtained over 15 times through the Penta-Guide Phantom installed with off-set shift values along six translational (Translation; TX, TY, TZ) and rotational (Rotation, Pitch; RX, Roll; RY, Yaw; RZ) directions. Using this method, we compared the reference image and the registration image, and we analyzed the error calculated by measuring the positional accuracy of the modified 6DoF Couch. Results: The Air Cavity corresponding to the Pixel of the reference image and the registration image were all contained between 30 and 66, and the revealing high registration accuracy. Error between the modified off-set value of 6DoF Couch and the measured value along translational directions were $0.25{\pm}0.18mm$ in the TX direction, $0.25{\pm}0.25mm$ in the TY direction, and $0.36{\pm}0.2mm$ in the TZ direction. Misalignments along the rotational axis were $0.18{\pm}0.08^{\circ}$ in the RX direction, $0.26{\pm}0.09^{\circ}$ in the RY direction, and $0.11{\pm}0.08^{\circ}$ in the RZ direction, it was corrected precisely for any value. Conclusion: Using the YCC QA Set, we were able to verify the error of 6DoF Couch along both the translational and rotational directions in a very simple method. This system would be useful in performing Daily IGRT QA of 6DoF Couch.

Contamination of Chinese Cabbage with 85Sr, 103Ru and 134Cs Related to Time of Foliar Application

Lee,Won-Yun,Park,Hyo-Guk,Choi,Yong-Ho,Lim,Kwang-Muk,Lee,Chang-Woo 대한방사선 방어학회 1998 방사선방어학회지 Vol.23 No.4

온실에서 Sr, Ru, Cs의 혼합용액을 배추의 생육중 다섯 차례에 걸쳐 엽면에 분무처리하였다. 처리된 핵종이 작물체에 의해 차단되는 정도는 핵종간에 차이가 없었고 처리시기가 수확기에 가까울수록 점점 증가하였다. 측정된 차단계수의 최고치는 0.87이었다. 작물체에 침적한 핵종의 수활시 잔류율은 처리시기에 따라 전체잎의 경우 Sr가 16∼58%, Ru이 15∼73%, Cs가 33∼64%였고 속잎(6장의 겉잎 제거)의 경우 각각 2∼35%, 0.4∼46% 및 14∼40%였다. 강우가 방사성 핵종의 환경제거 정도를 결정하는 데 중요한역할을 한다는 것이 확인되었다.배추의 생육후기 처리시 상단부를 묶었을 때 차단계수와 속잎 잔류율이 서너배씩 감소되었다. 본 연구결과는 배추의 생육중 사고방출시 배추내 핵종농도 예측 및 대책수립에 활용될 수 있다. A solution containing Sr, Ru and Cs was applied to Chinese cabbage in a greenhouse via foliar spraying at 5 different times during its growth. Interception of the applied activity by plant showed no difference among radionuclides and increased with decreasing time interval between application and harvest. The maximum interception factor observed was 0.87 Percentages of the intercepted activity remaining in the whole leaves at harvest varied 16∼58% for Sr, 15∼73% for Ru and 33∼64% for Cs, with application time and those for the inner leaves (without 6 outmost leaves) varied 2∼35%, 0.4∼46% and 14∼40%, respectively. It was demonstrated that rain plays an important role in weathering loss of the activity. Tying the upper end of the plant prior to the last application lowered interception and remaining activity in the inner leaves by factors of 3∼4. Present results can be referred to in predicting the radionuclide concentration in Chinese cabbage and deciding counter-measures at the time of an accidental release from the nuclear installation.

표적의 길이가 긴 환자의 용적회전변조 방사선치료 시 6DoF Couch의 유용성 평가

최영세,박효국,김세영,김주호,이상규,윤종원,조정희,Choi, Young Se,Park, Hyo Kuk,Kim, Se Young,Kim, Joo Ho,Lee, Sang Kyoo,Yoon, Jong Won,Cho, Jung Heui 대한방사선치료학회 2017 대한방사선치료학회지 Vol.29 No.2

목 적: 표적의 길이가 긴(length) 환자의 용적회전변조 방사선치료(V-MAT) 시 회전방향 오차의 크기에 따른 선량차이 경향을 $HexaPOD^{TM}$ evo RT system(6DoF couch)을 통해 알아보고 그 유용성을 평가하고자 하며, 이에 따른 회전오차 보정의 필요성을 제안하고자 한다. 대상 및 방법: 본원에서 치료를 받은 Esophagus cancer와 SCL을 포함한 Breast cancer 환자 중 HexaPOD 6DoF(Six-Degree of Freedom) couch를 사용한 10명을 대상으로 하였다. 6DoF couch를 이용하여 Rx(pitch), Ry(roll), Rz(yaw) 방향의 회전오차의 적용여부에 따른 선량차이를 알아보기 위하여 x, y, z축에 대한 자세오차를 확인하고, 자세 회전오차 값을 6DoF couch에 부여 임의의 오차를 발생시켜 변형된 선량계측 품질보증(Delivery Quality Assurance, DQA)을 시행, 점 선량과 감마값을 비교 분석하였다. 추가적으로 3cm의 직경에 5, 10, 15, 20 cm의 길이를 가진 각각의 표적의 치료계획에 회전오차의 크기를 $1^{\circ}$ 간격으로 적용한 후, 표적의 길이와 회전오차의 종류 및 크기에 따른 감마통과율의 변화양상을 확인했다. 결 과: 자세 회전오차가 적용된 경우의 점 선량과 감마통과율의 평균오차는 각각 Rx 방향에서 $2.50{\pm}1.11%$, $84.1{\pm}7.39%$, Ry 방향에서 $2.36{\pm}1.16%$, $81.0{\pm}8.49%$, Rz 방향에서 $2.35{\pm}1.10%$, $84.4{\pm}6.99%$를 나타냈다. 또한, 표적의 길이와 회전오차의 종류 및 크기에 따른 감마통과율 분석 결과 Ry 방향을 제외한 Rx와 Rz 방향에서 회전오차가 커질수록 감마통과율은 전반적으로 감소하는 경향을 보였으며, 특히 10 cm의 표적, Rz 방향으로 $2.5^{\circ}$ 회전오차가 부여된 경우에서 가장 낮은 감마통과율인 74.2 %를 나타냈다. 결 론: 표적의 길이가 긴 치료부위의 용적회전변조 방사선치료 시 회전오차의 보정은 필요하며, 6DoF couch의 사용은 환자자세의 재현성과 치료의 질적 효율을 높일 것으로 사료된다. Purpose: To evaluate the usefulness of the $HexaPOD^{TM}$ evo RT system(6DoF couch) and the tendency of dose difference according to size of rotational direction error for volumetric rotational modulated radiotherapy(V-MAT) in patients with long target lengths. Therefore, it is suggested to recommend the need for rotational error correction. Materials and Methods: Ten patients with Esophagus cancer or Breast cancer including SCL treated with HexaPOD 6DoF(Six-Degree of Freedom) couch were included in this study. 6DoF couch was used to measure the difference in dose according to the rotation error in the directions of Rx(pitch), Ry(roll), and Rz(yaw). Each rotation error was applied. Positioning variation on x, y and z axis was verified and random variations were made by 6DoF couch with positioning variation. Modified DQA is conducted and point dose and gamma value are analyzed and compared. In addition, after applying the rotation error every $1^{\circ}$ to treatment plans of each target with a diameter of 3 cm, 5, 10, 15, and 20 cm respectively, gamma passing rate is being monitored by its aspect of change according to types and sizes of the target length and rotation error. Results: Mean error of the point dose and Gamma passing rate when the position variation was applied were $2.50{\pm}1.11%$ and $84.1{\pm}7.39%$ in the Rx direction, $2.36{\pm}1.16%$, and $81.0{\pm}8.49%$ in the Ry, $2.35{\pm}1.10%$ and $84.4{\pm}6.99%$ in the Rz direction, respectively. As a result of analysis on gamma passing rate according to types and sizes of the target length and rotation error, the gamma passing rate tended to decrease with increasing rotation error in the Rx and Rz directions except Ry direction. In particular, the lowest gamma passing rate (74.2 %) was in the case of $2.5^{\circ}$ rotation error in Rz direction of the target of 10 cm. Conclusion: The correction of the rotational error is needed for volumetric modulated radiotherapy of the treatment area with a long target length, and the use of 6DoF couch will improve the reproducibility of the patient position and the quality of the treatment.