title: Extension of Fourier methods to the calculation of effective depths in heterogeneous media of arbitrary contour.
abstract: The description of patient contours and internal structures by means of truncated Fourier series can be extended to continuous contours of arbitrary shape and location by expressing the x and z Cartesian coordinates of the contour as independent Fourier series in a parameter t. An analytic equation for the intersection of the contour and a ray line is then written as an equation in the parameter t. The equation can be solved using numerical methods yielding the Cartesian coordinates of the intersection point directly.
mesh_terms: D005583:Fourier Analysis; D006801:Humans; D011829:Radiation Dosage