Can microdosimetry be the bridge between micro- and broad-beam experiments?

Sato, Tatsuhiko   

In the ICRU report 36 entitled "microdosimetry", the specific energy, z, is defined as the quotient of the energy imparted in microscopic site by its mass. The specific energy is a stochastic quantity, and its average value is equal to the macroscopic absorbed dose D. Introducing the concept of z, the difference between micro- and broad-beam experiments can be simply expressed by the difference of the probability densities of z in sub-cellular or cellular scales. As examples, cell survival fractions obtained using micro- and broad-beams were re-analyzed based on the probability densities of z in chromatin and cell-nucleus scales. The results of the analysis together with the discussion on the influence of the divergence of the probability density of z on the cell survival fractions will be presented at the meeting.