The scaling method applied to beta particle line sources with a finite diameter

Abstract

The well-known scaling method for planar and punctiform beta particle sources is extended to the case of a cylindrical source with a length larger than the beta particle range times two and with an infinitesimal or finite diameter. The equation for a spherical source with a finite diameter is also given. As a means of illustration, previously measured and simulated radial depth-dose distributions of a 40-mm-long prototype 188W/188Re intravascular beta source in polymethylmethacrylate are scaled to H2O and compared with simulations in the latter medium. The results suggest that the scaling method is accurate to within about 3%, provided that the finite diameter of the source is taken into account. © 2002 American Association of Physicists in Medicine.