The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Sungjoon Ye - One of the best experts on this subject based on the ideXlab platform.
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su gg t 386 monte carlo study of absorbed dose to solid water for External Auditing
Medical Physics, 2010Co-Authors: Joong Wan Park, Yong Hyun Park, Chang Heon Choi, Yunshik Choi, Sungji Park, Sungjoon YeAbstract:Purpose: An External audit for radiotherapy has been performed by the third parties to maintain a uniform quality of patient care among different facilities. Among a lot of Auditing items, we developed a method to determine absorbed dose to water from Farmer‐type ion‐chamber measurements in solid water within the context of AAPM TG‐51 protocol. The AAPM T‐51 protocol has liquid water as a phantom material for clinical reference dosimetry. Instead of liquid water, the use of a solid phantom is convenient for an External Auditing of busy clinics. Method and Materials: Due to different compositions and densities of solid water, correction factor for irradiation geometry and chamber responses are needed to convert measurements in solid water into absorbed dose to water. To avoid the complexity of measurement we kept the reference condition of solid water identical to that of water. The compositions and homogeneity of commercial solid water are varied among different manufactures and not consistent with the compositions provided by manufacturers. Therefore, the compositions of solid water used in this study were experimentally determined by using an electron probe micro‐analyzer (EPMA). The absorbed dose conversion factors for the solid water phantom were measured and, calculated by using the EGSnrc Monte Carlo code system. Results:Measured and calculated conversion factors under the reference condition were in a range of 1.00 – 1.005 for 6–15 MV photon beams, and 1.001 – 1.021 for 6–20 MeV electron beams. The total uncertainty of TG‐51 protocol measurement using solid water was determined to be ±1.5%. Conclusion: The measurement time (including setup time of a solid water phantom and a chamber for several photon and electron beams) was typically less than 30 minutes for External Auditing. Conflict of Interest: Research sponsored by Korea Institution of Nuclear Safety Corporation
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External Auditing on absorbed dose using a solid water phantom for domestic radiotherapy facilities
The Journal of The Korean Society for Therapeutic Radiology and Oncology, 2010Co-Authors: Chang Heon Choi, Jong Min Park, Yang Kyun Park, Sungjoon YeAbstract:목 적: 제 3기관에 의해 독립적으로 수행된 방사선 치료 빔의 흡수 선량을 외부 감사의 결과로 보고 한다. 이를 위해 쉽고 편리하게 설치 가능 한 고체 팬텀을 이용하여 흡수 선량을 측정하는 방법을 개발했다. 대상 및 방법: 2008년 12개 방사선 치료 시설에서 외부 감사 프로그램에 참여하였고 47개의 광자선과 전자선의 제 3기관에 의해 American Association of Physicists in Medicine (AAPM) task group (TG)-51 프로토콜을 사용하여 독립적으로 교정되었다. AAPM TG-51 프로토콜은 물에서의 측정을 권고 하고 있지만 팬텀으로 물은 바쁜 병원 상황에선 몇 가지 단점이 있다. 설치와 수송이 편리하고 재현성이 있는 고체 팬텀을 사용하였다. 광자선과 전자선에 대한 물과 고체 팬텀 사이의 선량 보정인자는 스케일링 방법과 실험적 측정에 의해 결정되었다. 결 과: 대부분의 빔은(74%) 제3기관의 프로토콜로 측정한 결과 2%의 편차 이내였다. 그러나 20개 중 2개의 광자선과 27개 중 3개의 전자선은 허용범위(3%)를 초과 하였다. 특히 그중 2개의 빔은 10% 이상의 편차를 보여주고 있다. 6 MV 초과의 고에너지 광자선은 보정인자가 없었다. 6 MV 광자선의 경우 고체 팬텀에서의 흡수선량은 물에서의 흡수 선량보다 0.4% 작게 나타났다. 전자선에 대한 보정인자도 결정되었는데 전자선의 에너지가 증가함에 따라 보정인자는 작아지는 경향을 보여준다. 고체팬텀을 사용한 TG-51 프로토콜의 측정 오차는 ${\pm}1.22%$ 로 나타났다. 결 론: 개발된 방법은 다기관 임상 연구의 인증 프로그램에 참여할 수 있는 외부 감사 기관 프로그램에 성공적으로 적용되었다. 이 선량측정은 선량을 측정하기 위한 시간을 줄이고 물을 설치할 때의 생길 수 있는 측정오차를 감소시킨다. 【Purpose: We report the results of an External audit on the absorbed dose of radiotherapy beams independently performed by third parties. For this effort, we developed a method to measure the absorbed dose to water in an easy and convenient setup of solid water phantom. Materials and Methods: In 2008, 12 radiotherapy centers voluntarily participated in the External Auditing program and 47 beams of X-ray and electron were independently calibrated by the third party’s American Association of Physicists in Medicine (AAPM) task group (TG)-51 protocol. Even though the AAPM TG-51 protocol recommended the use of water, water as a phantom has a few disadvantages, especially in a busy clinic. Instead, we used solid water phantom due to its reproducibility and convenience in terms of setup and transport. Dose conversion factors between solid water and water were determined for photon and electron beams of various energies by using a scaling method and experimental measurements. Results: Most of the beams (74%) were within ${\pm}2%$ of the deviation from the third party's protocol. However, two of 20 X-ray beams and three of 27 electron beams were out of the tolerance ( ${\pm}3%$ ), including two beams with a >10% deviation. X-ray beams of higher than 6 MV had no conversion factors, while a 6 MV absorbed dose to a solid water phantom was 0.4% less than the dose to water. The electron dose conversion factors between the solid water phantom and water were determined: The higher the electron energy, the less is the conversion factor. The total uncertainty of the TG-51 protocol measurement using a solid water phantom was determined to be ${\pm}1.5%$ . Conclusion: The developed method was successfully applied for the External Auditing program, which could be evolved into a credential program of multi-institutional clinical trials. This dosimetry saved time for measuring doses as well as decreased the uncertainty of measurement possibly resulting from the reference setup in water.】
Joong Wan Park - One of the best experts on this subject based on the ideXlab platform.
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su gg t 386 monte carlo study of absorbed dose to solid water for External Auditing
Medical Physics, 2010Co-Authors: Joong Wan Park, Yong Hyun Park, Chang Heon Choi, Yunshik Choi, Sungji Park, Sungjoon YeAbstract:Purpose: An External audit for radiotherapy has been performed by the third parties to maintain a uniform quality of patient care among different facilities. Among a lot of Auditing items, we developed a method to determine absorbed dose to water from Farmer‐type ion‐chamber measurements in solid water within the context of AAPM TG‐51 protocol. The AAPM T‐51 protocol has liquid water as a phantom material for clinical reference dosimetry. Instead of liquid water, the use of a solid phantom is convenient for an External Auditing of busy clinics. Method and Materials: Due to different compositions and densities of solid water, correction factor for irradiation geometry and chamber responses are needed to convert measurements in solid water into absorbed dose to water. To avoid the complexity of measurement we kept the reference condition of solid water identical to that of water. The compositions and homogeneity of commercial solid water are varied among different manufactures and not consistent with the compositions provided by manufacturers. Therefore, the compositions of solid water used in this study were experimentally determined by using an electron probe micro‐analyzer (EPMA). The absorbed dose conversion factors for the solid water phantom were measured and, calculated by using the EGSnrc Monte Carlo code system. Results:Measured and calculated conversion factors under the reference condition were in a range of 1.00 – 1.005 for 6–15 MV photon beams, and 1.001 – 1.021 for 6–20 MeV electron beams. The total uncertainty of TG‐51 protocol measurement using solid water was determined to be ±1.5%. Conclusion: The measurement time (including setup time of a solid water phantom and a chamber for several photon and electron beams) was typically less than 30 minutes for External Auditing. Conflict of Interest: Research sponsored by Korea Institution of Nuclear Safety Corporation
Chang Heon Choi - One of the best experts on this subject based on the ideXlab platform.
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su gg t 386 monte carlo study of absorbed dose to solid water for External Auditing
Medical Physics, 2010Co-Authors: Joong Wan Park, Yong Hyun Park, Chang Heon Choi, Yunshik Choi, Sungji Park, Sungjoon YeAbstract:Purpose: An External audit for radiotherapy has been performed by the third parties to maintain a uniform quality of patient care among different facilities. Among a lot of Auditing items, we developed a method to determine absorbed dose to water from Farmer‐type ion‐chamber measurements in solid water within the context of AAPM TG‐51 protocol. The AAPM T‐51 protocol has liquid water as a phantom material for clinical reference dosimetry. Instead of liquid water, the use of a solid phantom is convenient for an External Auditing of busy clinics. Method and Materials: Due to different compositions and densities of solid water, correction factor for irradiation geometry and chamber responses are needed to convert measurements in solid water into absorbed dose to water. To avoid the complexity of measurement we kept the reference condition of solid water identical to that of water. The compositions and homogeneity of commercial solid water are varied among different manufactures and not consistent with the compositions provided by manufacturers. Therefore, the compositions of solid water used in this study were experimentally determined by using an electron probe micro‐analyzer (EPMA). The absorbed dose conversion factors for the solid water phantom were measured and, calculated by using the EGSnrc Monte Carlo code system. Results:Measured and calculated conversion factors under the reference condition were in a range of 1.00 – 1.005 for 6–15 MV photon beams, and 1.001 – 1.021 for 6–20 MeV electron beams. The total uncertainty of TG‐51 protocol measurement using solid water was determined to be ±1.5%. Conclusion: The measurement time (including setup time of a solid water phantom and a chamber for several photon and electron beams) was typically less than 30 minutes for External Auditing. Conflict of Interest: Research sponsored by Korea Institution of Nuclear Safety Corporation
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External Auditing on absorbed dose using a solid water phantom for domestic radiotherapy facilities
The Journal of The Korean Society for Therapeutic Radiology and Oncology, 2010Co-Authors: Chang Heon Choi, Jong Min Park, Yang Kyun Park, Sungjoon YeAbstract:목 적: 제 3기관에 의해 독립적으로 수행된 방사선 치료 빔의 흡수 선량을 외부 감사의 결과로 보고 한다. 이를 위해 쉽고 편리하게 설치 가능 한 고체 팬텀을 이용하여 흡수 선량을 측정하는 방법을 개발했다. 대상 및 방법: 2008년 12개 방사선 치료 시설에서 외부 감사 프로그램에 참여하였고 47개의 광자선과 전자선의 제 3기관에 의해 American Association of Physicists in Medicine (AAPM) task group (TG)-51 프로토콜을 사용하여 독립적으로 교정되었다. AAPM TG-51 프로토콜은 물에서의 측정을 권고 하고 있지만 팬텀으로 물은 바쁜 병원 상황에선 몇 가지 단점이 있다. 설치와 수송이 편리하고 재현성이 있는 고체 팬텀을 사용하였다. 광자선과 전자선에 대한 물과 고체 팬텀 사이의 선량 보정인자는 스케일링 방법과 실험적 측정에 의해 결정되었다. 결 과: 대부분의 빔은(74%) 제3기관의 프로토콜로 측정한 결과 2%의 편차 이내였다. 그러나 20개 중 2개의 광자선과 27개 중 3개의 전자선은 허용범위(3%)를 초과 하였다. 특히 그중 2개의 빔은 10% 이상의 편차를 보여주고 있다. 6 MV 초과의 고에너지 광자선은 보정인자가 없었다. 6 MV 광자선의 경우 고체 팬텀에서의 흡수선량은 물에서의 흡수 선량보다 0.4% 작게 나타났다. 전자선에 대한 보정인자도 결정되었는데 전자선의 에너지가 증가함에 따라 보정인자는 작아지는 경향을 보여준다. 고체팬텀을 사용한 TG-51 프로토콜의 측정 오차는 ${\pm}1.22%$ 로 나타났다. 결 론: 개발된 방법은 다기관 임상 연구의 인증 프로그램에 참여할 수 있는 외부 감사 기관 프로그램에 성공적으로 적용되었다. 이 선량측정은 선량을 측정하기 위한 시간을 줄이고 물을 설치할 때의 생길 수 있는 측정오차를 감소시킨다. 【Purpose: We report the results of an External audit on the absorbed dose of radiotherapy beams independently performed by third parties. For this effort, we developed a method to measure the absorbed dose to water in an easy and convenient setup of solid water phantom. Materials and Methods: In 2008, 12 radiotherapy centers voluntarily participated in the External Auditing program and 47 beams of X-ray and electron were independently calibrated by the third party’s American Association of Physicists in Medicine (AAPM) task group (TG)-51 protocol. Even though the AAPM TG-51 protocol recommended the use of water, water as a phantom has a few disadvantages, especially in a busy clinic. Instead, we used solid water phantom due to its reproducibility and convenience in terms of setup and transport. Dose conversion factors between solid water and water were determined for photon and electron beams of various energies by using a scaling method and experimental measurements. Results: Most of the beams (74%) were within ${\pm}2%$ of the deviation from the third party's protocol. However, two of 20 X-ray beams and three of 27 electron beams were out of the tolerance ( ${\pm}3%$ ), including two beams with a >10% deviation. X-ray beams of higher than 6 MV had no conversion factors, while a 6 MV absorbed dose to a solid water phantom was 0.4% less than the dose to water. The electron dose conversion factors between the solid water phantom and water were determined: The higher the electron energy, the less is the conversion factor. The total uncertainty of the TG-51 protocol measurement using a solid water phantom was determined to be ${\pm}1.5%$ . Conclusion: The developed method was successfully applied for the External Auditing program, which could be evolved into a credential program of multi-institutional clinical trials. This dosimetry saved time for measuring doses as well as decreased the uncertainty of measurement possibly resulting from the reference setup in water.】
Yunshik Choi - One of the best experts on this subject based on the ideXlab platform.
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su gg t 386 monte carlo study of absorbed dose to solid water for External Auditing
Medical Physics, 2010Co-Authors: Joong Wan Park, Yong Hyun Park, Chang Heon Choi, Yunshik Choi, Sungji Park, Sungjoon YeAbstract:Purpose: An External audit for radiotherapy has been performed by the third parties to maintain a uniform quality of patient care among different facilities. Among a lot of Auditing items, we developed a method to determine absorbed dose to water from Farmer‐type ion‐chamber measurements in solid water within the context of AAPM TG‐51 protocol. The AAPM T‐51 protocol has liquid water as a phantom material for clinical reference dosimetry. Instead of liquid water, the use of a solid phantom is convenient for an External Auditing of busy clinics. Method and Materials: Due to different compositions and densities of solid water, correction factor for irradiation geometry and chamber responses are needed to convert measurements in solid water into absorbed dose to water. To avoid the complexity of measurement we kept the reference condition of solid water identical to that of water. The compositions and homogeneity of commercial solid water are varied among different manufactures and not consistent with the compositions provided by manufacturers. Therefore, the compositions of solid water used in this study were experimentally determined by using an electron probe micro‐analyzer (EPMA). The absorbed dose conversion factors for the solid water phantom were measured and, calculated by using the EGSnrc Monte Carlo code system. Results:Measured and calculated conversion factors under the reference condition were in a range of 1.00 – 1.005 for 6–15 MV photon beams, and 1.001 – 1.021 for 6–20 MeV electron beams. The total uncertainty of TG‐51 protocol measurement using solid water was determined to be ±1.5%. Conclusion: The measurement time (including setup time of a solid water phantom and a chamber for several photon and electron beams) was typically less than 30 minutes for External Auditing. Conflict of Interest: Research sponsored by Korea Institution of Nuclear Safety Corporation
Yong Hyun Park - One of the best experts on this subject based on the ideXlab platform.
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su gg t 386 monte carlo study of absorbed dose to solid water for External Auditing
Medical Physics, 2010Co-Authors: Joong Wan Park, Yong Hyun Park, Chang Heon Choi, Yunshik Choi, Sungji Park, Sungjoon YeAbstract:Purpose: An External audit for radiotherapy has been performed by the third parties to maintain a uniform quality of patient care among different facilities. Among a lot of Auditing items, we developed a method to determine absorbed dose to water from Farmer‐type ion‐chamber measurements in solid water within the context of AAPM TG‐51 protocol. The AAPM T‐51 protocol has liquid water as a phantom material for clinical reference dosimetry. Instead of liquid water, the use of a solid phantom is convenient for an External Auditing of busy clinics. Method and Materials: Due to different compositions and densities of solid water, correction factor for irradiation geometry and chamber responses are needed to convert measurements in solid water into absorbed dose to water. To avoid the complexity of measurement we kept the reference condition of solid water identical to that of water. The compositions and homogeneity of commercial solid water are varied among different manufactures and not consistent with the compositions provided by manufacturers. Therefore, the compositions of solid water used in this study were experimentally determined by using an electron probe micro‐analyzer (EPMA). The absorbed dose conversion factors for the solid water phantom were measured and, calculated by using the EGSnrc Monte Carlo code system. Results:Measured and calculated conversion factors under the reference condition were in a range of 1.00 – 1.005 for 6–15 MV photon beams, and 1.001 – 1.021 for 6–20 MeV electron beams. The total uncertainty of TG‐51 protocol measurement using solid water was determined to be ±1.5%. Conclusion: The measurement time (including setup time of a solid water phantom and a chamber for several photon and electron beams) was typically less than 30 minutes for External Auditing. Conflict of Interest: Research sponsored by Korea Institution of Nuclear Safety Corporation
