Many commercial treatment planning systems available today employ traditional dose calculation formulae in their interstitial brachytherapy source calculation algorithms. The 1995 AAPM report on interstitial brachytherapy source dosimetry recommended a new dose calculational formalism and presented a technique for adopting it on systems which embody traditional formalism. In order to comply with these recommendations on our system, the transformations for implementing a one dimensional isotropic point source model were modified by coupling the published anisotropy and radial dose corrections and fitting them to a fifth order polynomial. Using this approach, a more accurate dose calculation is obtained.