Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series:Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System Sean J.Domal1,Camilo M.Correa-Alfonso...Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series:Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System Sean J.Domal1,Camilo M.Correa-Alfonso1,Colin J.Paulbeck2,Keith T.Griffin3,4,Tatsuhiko Sato5,Sachiyo Funamoto6,Harry M.Cullings6,Stephen D.Egbert7,Akira Endo8,Nolan E.Hertel4,Choonsik Lee3,Wesley E.Bolch9(1.Medical Physics Program,College of Medicine,University of Florida,Gainesville,FL;2.Department of Radiology,Johns Hopkins University,Baltimore,MD;3.National Cancer Institute,National Institutes of Health,Rockville,MD;4.George W.Woodruff School of Mechanical Eng.,Georgia Institute of Technology,Atlanta,GA;5.Nuclear Science and Engineering Center,Japan Atomic Energy Agency,Tokaimura,Japan;6.Department of Statistics,Radiation Effects Research Foundation,Hiroshima,Japan;7.Consultant,San Diego,CA;8.Nuclear Science Research Institute,Japan Atomic Energy Agency,Tokaimura,Japan;9.J.Crayton Pruitt Family Department of Biomedical Eng.,University of Florida,Gainesville,FL USA)Abstract:Organ dosimetry data of the atomic bomb survivors and the resulting cancer risk models derived from these data are currently assessed within the DS02 dosimetry system developed through the Joint US-Japan Dosimetry Working Group.In DS02,the anatomical survivor models are limited to three hermaphroditic stylized phantoms—an adult(55 kg),a child(19.8 kg),and an infant(9.7 kg)—that were originally designed for the preceding DS86 dosimetry system.As such,organ doses needed for assessment of in-utero cancer risks to the fetus have continued to rely upon the use of the uterine wall in the adult non-pregnant stylized phantom as the dose surrogate for all fetal organs regardless of gestational age.展开更多
Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irra...Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irradiators are Cs-137 OB6 irradiator and X-ray irradiators at the Protection level SSDL;and Co-60 irradiator at the Therapy Level SSDL. PTW UNIDOS electrometer and LS01 Ionization chamber were used at the Protection Level to obtain doses for both Cs-137 OB6 and X-ray irradiators while an IBA farmer type ionization chamber and an IBA DOSE 1 electrometer were used at the Protection Level SSDL. Single/multiple exposure method and graphical method were used in the determination of the timer error for the three irradiators. The timer error obtained for Cs-137 OB6 irradiator was 0.48 ± 0.01 s, the timer error for the X-ray irradiator was 0.09 ± 0.01 s while the timer error obtained for GammaBeam X200 was 1.21 ± 0.04 s. It was observed that the timer error is not affected by source to detector distance. It was also observed that the timer error of Co-60 Gamma X200 irradiator is increasing with the age of the machine. Source to detector distance and field size do not contribute towards the timer error of the irradiators. The timer error of the Co-60 Gamma X200 irradiator (the only irradiator among the irradiators with a pneumatic system) increases with the age of the irradiator.展开更多
文摘Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series:Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System Sean J.Domal1,Camilo M.Correa-Alfonso1,Colin J.Paulbeck2,Keith T.Griffin3,4,Tatsuhiko Sato5,Sachiyo Funamoto6,Harry M.Cullings6,Stephen D.Egbert7,Akira Endo8,Nolan E.Hertel4,Choonsik Lee3,Wesley E.Bolch9(1.Medical Physics Program,College of Medicine,University of Florida,Gainesville,FL;2.Department of Radiology,Johns Hopkins University,Baltimore,MD;3.National Cancer Institute,National Institutes of Health,Rockville,MD;4.George W.Woodruff School of Mechanical Eng.,Georgia Institute of Technology,Atlanta,GA;5.Nuclear Science and Engineering Center,Japan Atomic Energy Agency,Tokaimura,Japan;6.Department of Statistics,Radiation Effects Research Foundation,Hiroshima,Japan;7.Consultant,San Diego,CA;8.Nuclear Science Research Institute,Japan Atomic Energy Agency,Tokaimura,Japan;9.J.Crayton Pruitt Family Department of Biomedical Eng.,University of Florida,Gainesville,FL USA)Abstract:Organ dosimetry data of the atomic bomb survivors and the resulting cancer risk models derived from these data are currently assessed within the DS02 dosimetry system developed through the Joint US-Japan Dosimetry Working Group.In DS02,the anatomical survivor models are limited to three hermaphroditic stylized phantoms—an adult(55 kg),a child(19.8 kg),and an infant(9.7 kg)—that were originally designed for the preceding DS86 dosimetry system.As such,organ doses needed for assessment of in-utero cancer risks to the fetus have continued to rely upon the use of the uterine wall in the adult non-pregnant stylized phantom as the dose surrogate for all fetal organs regardless of gestational age.
文摘Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irradiators are Cs-137 OB6 irradiator and X-ray irradiators at the Protection level SSDL;and Co-60 irradiator at the Therapy Level SSDL. PTW UNIDOS electrometer and LS01 Ionization chamber were used at the Protection Level to obtain doses for both Cs-137 OB6 and X-ray irradiators while an IBA farmer type ionization chamber and an IBA DOSE 1 electrometer were used at the Protection Level SSDL. Single/multiple exposure method and graphical method were used in the determination of the timer error for the three irradiators. The timer error obtained for Cs-137 OB6 irradiator was 0.48 ± 0.01 s, the timer error for the X-ray irradiator was 0.09 ± 0.01 s while the timer error obtained for GammaBeam X200 was 1.21 ± 0.04 s. It was observed that the timer error is not affected by source to detector distance. It was also observed that the timer error of Co-60 Gamma X200 irradiator is increasing with the age of the machine. Source to detector distance and field size do not contribute towards the timer error of the irradiators. The timer error of the Co-60 Gamma X200 irradiator (the only irradiator among the irradiators with a pneumatic system) increases with the age of the irradiator.
