X線スペクトルによる吸収線量変換係数 : 半価層による方法との比較

抄録

When the absorbed dose conversion factor of the x-rays is looked for, generally it is being done how to measure the effective energy (keV) from the half-value layer. But, spectrum measurement is necessary to evaluate quality of x-ray precisely. So, 2.94% of the maximum differences were in the water, soft tissue, and 20.93 % of the maximum differences were in search of absorbed dose conversion factor due to the halfvalue layer and the spectrum as a compared result by cortical bone. And, when a x-ray tube voltage rose, this difference showed a tendency of spreading out. A cause was because the rates of the photon of the higher energy than the energy measured with effective energy increased by a x-ray tube voltage's rising. The ratio of the mass energy absorption coefficient which faces air like cortical bone should be careful because an error by the absorbed dose conversion factor grows big when a absorbed dose conversion factor is measured by the big absorption medium, though it is as the difference in absorbed dose conversion factor is compared with an error by the dosimeter and there is no problem in the water, soft tissue.