A script was developed that automates the extraction of gamma source spectra from the buildup and decay results of the codes CINDER’90 or SP-FISPACT, and then generates a source description for subsequent gamma transport analysis with MCNP(X). This new script was used to calculate remanent dose rates from activated components in accelerator facilities. In this paper, details of this new script are presented and comparisons are made between the calculated and measured dose rates for two cases. First, the dose to personnel involved in dismantling part of the original beam transfer line to GANTRY 1 of the proton radiotherapy station at PSI is estimated. The beamline was dismantled to allow a new operational mode using 250 MeV protons from the COMET superconducting cyclotron rather than protons from the 590 MeV PSI main cyclotron. In the second example, calculations and measurements of gamma dose rates from a retired depleted uranium target at Argonne’s Intense Pulsed Neutron Source are presented. These dose rates are important for subsequent target handling operations.