Figure 3. Relative photon energy spectra at layers “1” and “2” for the inhomogeneous bone (and water phantom using a circular field of 5 cm diameter. Water thicknesses are equal to (a) 0.5, (b) 1, (c) 3, and (d) 5 mm. The insets in the up the spectral curves in the energy range of 15–50 keV. All special curves were normalized to the maximum intensity of their Bremsstrahlung spectra.