QUALITY FACTOR FOR LOW-ENERGY BETA-EMITTERS

The experimental evidence for the RBE of beta-particles from tritiated water is reviewed. Reported values are in the range 1–2. This variation is not remarkable in view of the different end points used but it is also due to experimental errors, to different views concerning the spatial distribution of dose, to the quality of the reference radiation and to dose rate. The results are reviewed in relation to recommendations of I.C.R.P. concerning QF and it is concluded that a value of QF different from unity for either tritium or other beta-emitters is hardly justified. © 1968 Health Physics Society.