an improved , quantitative version of the partial fluence model [ med . phys . 14 , 585 ( 1987 ) ] for the calculation of dose perturbations at media interfaces in photon beams is presented and compared with measurements made at interfaces between polystyrene and materials ranging in atomic number from aluminum to lead , for photon beams ranging in energy from 60co to 24 mv .
C0392762
quantitative
C1514721
ranging