VALIDITY OF THE CONCEPT OF ABSORBED DOSE AS A PHYSICAL QUANTITY

The concept of the ''absorbed dose'' of ionizing radiation is scrutini zed from physical point of view. It is shown that the concept and defi nition of the quantity in the ICRU system is disqualified as a physica l quantity and the absorbed dose can not always be a ''measure of caus e'' 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 o f introducing the quantity. Trials to remove these difficulties are ma de. However, it is also shown there still exists an essential problem that cannot be solved by improving the formulation.