title: The lens coupling efficiency in megavoltage imaging.
abstract: In TV-based megavoltage imaging systems it is useful to be able to estimate the geometrical efficiency g2 of the camera lens. It is shown that the appropriate expression is g2 = (16n2)-1 X [F(1 + 1/m)]-2, where n is the refractive index of the scintillator, F is the F-number of the lens and m is the optical magnification. This expression yields estimates for g2 that are 5 to 10 times smaller than the estimates that have appeared previously in the literature.
authors.affiliation: Department of Physics, Royal Marsden Hospital/Institute of Cancer Research, Sutton, Surrey, United Kingdom.
authors.forename: W
authors.initials: W
authors.lastname: Swindell
mesh_terms: D011856:Radiographic Image Enhancement; D013679:Technology, Radiologic; D013690:Television