  We have developed a simplified method of treating the radiative acceleration
of dusty flows. This method retains the sharp impulse at the dust destruction
radius that is a feature of frequency dependent radiative transfer, whilst
placing minimal demands on computing resources. As such, it is suitable for
inclusion in hydrodynamic codes. We have applied this method to the formation
of massive stars in spherical geometry, and find that the fraction of a cloud
which can accrete on to the central star is a strong function of the Jeans'
Number and density profile of the cloud. Massive star formation is favoured by
cold homogeneous conditions, as might result in regions where gas is swept up
by some external triggering agent. We find (in contrast to previous authors)
that massive star formation does not require a depleted dust mixture, although
the use of dust at typical interstellar abundances does reduce the final
stellar mass compared to cores formed from a depleted mixture.
