ABSTRACT
The direct impact of experimental microdosimetry on the clinical practice of radiation therapy has been modest and care must be taken not to overstate its value. However, different radiation weighting factors are needed to correct for differences in biological effectiveness whenever radiation beams of different quality or linear energy transfer (LET) are used in therapy. The measurement of lineal energy dose distributions or their averages has been investigated for this purpose and found to be of considerable pragmatic value. Experimental microdosimetry is of particular interest when results from different clinics are to be compared or when changes of radiation quality are introduced. This has been found to be the case even if there is no agreed on direct relationship between measured microdosimetric quantities and a therapeutic beam’s actual clinical biological effectiveness. In this chapter an attempt is made to illustrate better the connection between microdosimetric single-event distributions or their mean values and results observed in radiobiology 104and radiation therapy. The examples chosen reflect the interests of the authors and are by no means meant to be comprehensive or complete.
