The whole-body neutron dose was obtained from the measurement of21Na-activity in three parts of the phantom (head, torso, legs). The measurement of32P-activity in samples of nails and hairs was used for determination of the neutron dose distribution. Doses in an interval of (0.1—0.5) J. kg−1was determined with relative errors of 17.4% (from the24Na-activity) and 23.3% (from the32P-activity); in an interval of (0.01—0.11) J. Kg−1with a relative error of 45% from the24Na-activity. The approximation of the real spectrum by the “dE/E” spectrum in a neutron energy interval of 0.48 eV to 1 MeV and by the undisturbed fission spectrum above 0.1 MeV energy of neutrons results in errors of 69.8% for a dose based on the24Na-activity in fast neutron region and of 28.8% for the same dose based on32P-activity. The error of the dose based on the24Na-activity will be of 44.9% in the region of intermediate neutrons.