-13” t _ ; rem is the unit of Dose Equivalent (DE) 18 . . 8 The DE is obtained by multiplying the absorbed dose in rad by modifying factors to correct for these observed differences in the magnitude of the effect. As a consequence, the magnitude of the effect will be the same for a given DE regardless of the mature of the radiation or the manner of radiation. B. Modifying Factors _At the present time, two modifying factors are employed. *e One is the Quality Factor (QF) which accounts for differences in producing biological effects among various forms of radiation. the other is the Distribution Factor (DF) which accounts for the modification of the biological effects when a radionuclide is nonuniformly distributed in an organ. For example, the DE for X-ray to bone tissue is determined by using QF=l and DF=1, while that for Pu-239 in the bone is determined by using a QF=10 (to account for the greater effectiveness of alpha particle irradiation) and a DF=5 (to account for the peculiar distribution of Pu in the bone) A DE=50 rem from X-rays or Pu-23S would thus induce the same -humber of cancers in bone but the absorbed dose from the X-rays would be 50 rad while that from Pu-239 would be only 1 rad. 18/ NCRP Report No. .39, Cn. cit., p. 8l. 19/ ICRP Publication 11, On. cit., p. ’ 21.