In the current work, the organ and effective dose to MIRD-5 type phantoms due to external photon exposure in GST (Generic Source Term) geometries have been calculated through radiation transport simulations. GST geometries are intended for use together with the stochastic particle dispersion models being developed at the Swedish Defence Research Agency (FOI). The phantoms are situated on the ground and the source is either a spherical shell in air or a circular line source on the ground with a source radius ranging from 20 cm to 300 m. In previous work from FOI, results from similar calculations were reported without the ground and the ground source in the simulations. The simulations have been performed for monochromatic photon energies ranging from 50 keV to 2 MeV. The effective dose has been calculated according to the formalisms outlined in publications 60 and 103 of International Commission on Radiological Protection (ICRP). The statistical error in the calculated effective dose was low and generally below 0.2%. To the knowledge of the authors, there are no data published for the GST geometries used here so a direct comparison of the results is not feasible. However, the convergent data generated in this work, with satisfying low statistical error (< 2%), are traceable to reference radiation dose data by e.g. ICRP through benchmarked data reported by FOI in previous reports where essentially the same methods as in the current work have been applied.