This paper extends previous work to characterize neutron dosimetry in the v
icinity of Cf-252 brachytherapy sources. A general source is examined with
an arbitrary length, diameter, and encapsulation using Monte Carlo methods.
Fast neutron dosimetry and thermal neutron fluence rates were determined i
n a variety of clinically relevant media of varying dimensions. Applicator
Tube, point source, high dose rate VariSource, and high dose rate mu Select
ron source geometries were analyzed. Fast neutron dosimetry was relatively
independent of encapsulation thickness for an assortment of encapsulation m
aterials less than 2 mm thick. Large variations in phantom size made minima
l differences in the fast neutron dose close: to the source. Specific sourc
e geometries were compared with dosimetry obtained from a simplified point
model. The consequence of these results is a convenient means of accurately
predicting clinical fast neutron dosimetry characteristics around a genera
l Cf-252 brachytherapy source in a variety of media without requiring neutr
on transport. Thermal neutron fluence rates were determined for a variety o
f source encapsulation materials, encapsulation thicknesses, and phantom si
zes. At a distance of 3 cm from the source center, the thermal neutron flue
nce rate for a 30 cm diameter phantom was a 2.65 times greater than for a 1
0 cm diameter water phantom. These results demonstrate 252Cf thermal neutro
n fluence rate is relatively independent of encapsulation thickness and com
position, yet highly dependent on hydrogen mass density and phantom size fo
r phanta with diameters <30 cm. (C) 2000 American Association of Physicists
in Medicine. [S0094-2405(00)00712-4].