The present work introduces an alternative method for calculating the spatial distribution of interstitial fluence rate in laser-induced interstitial thermotherapy. The method originates from the un-simplified integral-differential radiant transport equation, which is then solved by the radial basis function collocation technique. After comparing with the Monte Carlo and finite volume methods, it is concluded that this method is able to provide accurate predictions of fluence rate distributions along the penetration depth, particularly around the boundary. (C) 2010 Elsevier Ltd. All rights reserved.