Calculating the effective dose of occupationally exposed persons in roentgen diagnosis

The radiation exposure of occupationally exposed staff was measured at tube voltages of 50, 80 and 100 kV. A typical arrangement for fluoroscopic examinations was chosen: the (standing) physician is exposed by the scattered radiation from a (lying) patient. The physician is represented by an Alderson-Rando-Phantom and a spherical phantom similar to an ICRU sphere. Measurements of the partial body dose were performed by film dosimetry in the Alderson-Rando-Phantom in a.p. and in lateral direction of the scattered radiation respectively. From these measurements the effective dose was calculated. The ambient equivalent dose H* (10) in the sphere phantom was determined by the same method. The latter results yield the conversion factor g, which describes the ratio effective dose E to ambient equivalent dose H* (10). A conversion factor of g = 0.3 was established by averaging over the tube voltage and the direction of the scattered radiation. Based on the guidelines 96/29/Euratom and the transition from old to new dose quantities a reduction of the dose limits for occupationally exposed persons by a factor of up to 3.75 will be necessary. Applying the conversion factors can almost compensate that reduction.