Figure 3.

Demonstration of tissue segmentation for lower (a) and higher (b) effective atomic number (Z) intervals in small animal dose calculations using 39 tissue types. Z is plotted as a function of mass density for ICRU tissues (squares), for tissue types required to achieve 2% dose calculation accuracy for a 120 kV beam based on Z differences (circles), and for the center of bins for segmentation with 0.02 g∕cm³ mass density bins (open triangles). Tissue types used for dose calculations are shown in closed triangles and separated by solid lines.