Test of active personal dosimeters for interventional radiology in realistic radiation fields

In Interventional radiology, the medical staff stands close to the patient during his exposure to X-rays. Consequently, they can be exposed to relatively high doses due to radiation scattered by the patient and the medical equipment. Contrary to the passive dosemeters which assess the doses a posteriori, APDs are able to warn the medical staff when doses and/or dose rates exceed pre-defined radiation protection limits. At interventional radiology workplaces, APDs must be able to measure low-energy photons (10-120 keV) and pulsed radiations with relatively high instantaneous dose rates delivered by medical X-rays generators. Six ADP models, considered as suitable for application in interventional radiology on the basis of the results of a previous comparison jointly organised by EURADOS and IAEA, were selected to carry out a new comparison in 2007. This included radiation fields able to mimic the scattered and pulsed X-ray radiation fields met at workplace in hospitals. Irradiations took place at CEA-LIST LNHB (Saclay, France) and IRSN (Fontenay-aux-Roses, France). This paper describes the irradiation assemblies both for realistic and classic calibration facilities. The reference values of the personal dose equivalent, Hp(10), were determined through measurements and simulations to calculate the response of the APDs. The results shed light on the ability of APDs to measure correctly the doses, when used in the specific low-energy spectra and dose rates of pulsed X- rays encountered in interventional radiology.