抄録
The concept of the “ absorbed dose'' of ionizing radiation is scrutinized from physical point of view. It is shown that the concept and definition of the quantity in the ICRU system is disqualified as a physical quantity and the absorbed dose can not always be a “ measure of cause'' in describing causality relation between radiation and effects on matter. The current absorbed dose depends even on the energy that have already been brought out from the matter, contrary to the intention of introducing the quantity. Trials to remove these difficulties are made. However, it is also shown there still exists an essential problem that cannot be solved by improving the formulation.
