Poster — Thur Eve — 32: Radiation Dose from a Proposed Measurement of Arsenic and Selenium in Human Skin

Dose measurements following 10 minute irradiations with a portable x‐ray fluorescence (XRF) spectrometer composed of a miniature x‐ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table‐top setup of the XRF spectrometer was used for all measurements. The setup included a stainless steel lid which served as a radiation shield. Two rectangular polyethylene skin/soft tissue phantoms with two cylindrical plaster of Paris bone phantoms (diameters of 5 and 10 mm) were used to study the effect of x‐ray beam attenuation and backscatter on the measured dose. Eight different irradiation experiments were performed. The average dose rate values measured with TLD chips within a 1×1 cm2 area were between 4.8 and 12.8 mGy min−1. The average dose rate values of the irradiations with 10 mm diameter bone phantom were higher than the corresponding values with the 5 mm diameter bone phantom. This demonstrated that the dose contribution of the bone backscattered radiation cannot be neglected. The dose measurements demonstrated that no significant health risks can be expected from a two minute irradiation of a commercial XRF spectrometer. The corresponding skin equivalent dose for a two minute irradiation was calculated to be 13.2 mSv. This value is lower than the ICRP Report 60 (1991) annual dose limit for the general population of 50 mSv for a 1×1 cm2 skin area.