Figure 4: Geometric depiction of the coordinates defining attenuation path length for the Jaszczak phantom. The center of the phantom represented by (xc,yc), the point source location by (x₀,y₀), the boundary point along angle θ_i(i = 1, 2) represented by (x^'_i,y^'_i) and the attenuation path length for the i^th angle represented by l_i