Neutron doses often come dominant in mazes of electron accelerator facilities in which X-rays of energies more than 10 MV are produced. A simple analytical method to calculate neutron doses in such a facility is developed. In the calculation procedure, it is assumed that the irradiation room is spherical in shape and the maze is cylindrical. Multipile reflection of neutrons is also considered using the albedo concept in the calculation. The procedure allows to exist a hanging wall over the entrance of the irradiation room and also multiple legs in the maze. All the parameters used in the calculation are given definitely in the procedure, and any experiment is unnecessary to determine value of the parameters. Comparison of the calculated results with experimental ones will be described in the following report.
Neutron dose equivalent rates are measured in the irradiation room and the maze of a medical electron accelerator facility. Are m-counter used for measurement is associated with a gate circuit to reject piled up signals caused by pulsed X-rays, so that it is possible to measure the neutrons without obstruction by the piled up signals even in the irradiation room. Counting loss of neutrons is mathematically corrected, and the correction factor comes nearly equal to 1.5 at dose points close to the entrance to the irradiation room when 14 MV X-rays are generated. The measurement in the maze agrees with the calculation reported in the preceding report in a factor less than 1.5 except for dose points close to the entrance to the irradiation room.
An evaluation of LH- and FSH-RIA BEAD kits based on IRMA was carried out. The results obtained with the methods characterized by the use of monoclonal antibodies, i.e., one is linked to solid phase, and another is isotopieally labeled, were compared with those determined by the Daiichi LH- and FSH-kits. Intra- and inter-assay precision, recovery, linearity, and specificity of both methods were favorable without exceptions. The cross reactivity of the LH kit to 5000 mIU/ml hCG revealed within the range of less than 3 mIU/ml. Significant correlations were observed between the results derived from conventional Daiichi LH- and FSH-kits. The results from the conventional kits exhibited 30 to 40% of those from the Daiichi kits, considered to be mainly due to the difference in standard calibrations used. Among the individuals within the normal menstrual cycle, the serum LH and FSH-levels determined by the present kits gave a typical pattern with a peak in the preovulatory phase. On the other hand, the LH- and FSH-values of individuals in normal pregnancy revealed strikingly decreased in comparison with those of non-pregnant women.
The shielding ability of radiation resistant gloves were examined. The gloves are made of lead loaded (as PbO2) polyvinyl chloride resin and are about 0.4 mm of thickness (70 mg/cm2) . Eleven test pieces were sampled from each of three gloves (total were thirty three) and the transmission rates for radiations (X-ray or γ-ray) through the test pieces were measured with radiation sources, 99mTc, 57Co, 133Ba, 133Xe and241Am. The differences of the transmission rates for radiations by the positions of the gloves were smaller than 15%, and the differences by three gloves were smaller than 5% in the case of 60 keV and 141 keV radiations. The average transmission rates for radiations in thirty three test pieces were about 40% for 30 keV radiation, about 90% for 80keV and 140keV radiations. The shielding characteristic of the gloves could be equivalent to about 0.026 mm thick lead plate.