[en] A comparison is made of the isotopic neutron sources ²⁵²Cf and ²³⁸Pu, Be for partial-body in vivo neutron activation analysis. Depth distributions of thermal neutron fluences in a water phantom are very similar for the two sources. The peak depth occurs at 5 cm. This value is approximately 2 cm less than the values obtained with uncollimated neutrons produced in broad-beam irradiations. With respect to the fluence-to-dose ratio, the ²⁵²Cf neutrons have an advantage of approximately 1.4 over the ²³⁸Pu, Be source. The use of ²⁵²Cf offers two additional advantages for the investigator. First, it minimises the on-line fast-neutron damage in Ge(Li) semiconductor detectors. Secondly, it is subject to much less stringent transport regulations than ²³⁸Pu, Be. The latter feature takes on particular importance in view of the increasing usefulness of transportable instruments for in vivo cadmium measurements at the workplace. (author)