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Interventional radiologists and staff members, during all their professional activities, are frequently exposed to protracted and fractionated low doses of ionizing radiation. Due to skin tissues and peripheral blood irradiation, these exposures can result in deterministic effects (radiodermatitis, aged skin, and hand depilation) or stochastic ones (skin and non-solid cancer incidence). The authors present a novel approach to perform online monitoring of the staff during their interventions by using a device based on an Active Pixel Sensor. The performance of the sensor as an X-ray radiation detector has been evaluated with a proper experimental setup: the number of photons and the generated charge have been assessed as dosimetric observables from the frames acquired by the sensor using a two-threshold clustering algorithm, the efficiency of which has been evaluated as well. The correlation of these observables with passive dosimeter dose measurements has been analyzed: a good linearity has been demonstrated, and the response difference between pulsed and continuous operational modes is reduced to less than 10%, marking a distinct improvement with respect to commercial Active Personal Dosimeters. [ABSTRACT FROM AUTHOR]

An electronic system based on a microcontroller architecture, devoted to interfacing a three-terminal, ultralow power (ULP) Metal OXide (MOX) gas sensor is presented. The sensor features a novel three-terminal configuration where the microheater is not galvanically isolated with respect to the MOX sensor. The system provides both control of the operating temperature and management of the acquired data. A Pulse Width Modulation (PWM) signal with variable duty cycle is used to provide power to the heating resistor in order to set the desired operating temperature. The heating resistance value is measured in the range (100–300) \Omega with a relative error of less than 1%. The circuit devoted to measuring the gas concentration is based on a logarithmic amplifier which measures the current flowing in the sensing layer of the sensor. The measurand range is 30 nA to 60 mA and the relative error of the measured current is less than 0.6%. The data acquisition system was successfully tested by acquiring data of a three-terminal ULP gas sensor located in an automatically controlled environmental chamber under benzene and \NO2 flow. [ABSTRACT FROM AUTHOR]