Evaluation of the use of a niobium filter for patient dose reduction in chest radiography.

The performance characteristics of a 50 microns niobium filter and a copper filter of equivalent thickness (0.15 mm) were compared for postero-anterior chest X-ray examination. Radiographs of 20 patients obtained using an automatic exposure control device showed no significant differences in image quality and exposure setting between the filters.

Effects of ionizing radiation on the metabolism and longitudinal growth of cartilaginous embryonic chick tibiae in vitro.

The effect of ionizing radiation on the metabolism and longitudinal growth of cartilaginous tibiae of 6.5-day-old chick embryos was studied in vitro over a 3-day period. Before being cultured, tibiae received absorbed doses of 2 to 200 Gy.

Conversion factor f for X-ray beam qualities, specified by peak tube potential and HVL value.

Conversion factors of exposure to absorbed dose f in compact bone, muscle, water and adipose tissue are deduced from the measured photon fluence spectra of x-ray beams with potentials from 50 to 250 kV. The results show that accurate determination of f requires beam quality specification not only by the HVL value but also by a second parameter, e.g.