Validation of ΓKa for diagnostic radiography in three different hospitals in the Lambayeque region, Peru

Abstract

Air Kerma was measured and compared with calculated air Kerma aiming to validate the use of air Kerma gamma factors. The air Kerma was measured in radiology departments in three hospitals at the Lambayeque region in Peru. In each department were obtained three times different radiographs, for each radiograph the X-ray operational parameters were recorded such us: voltage, current, and triggering time; the average values of these parameters, and the measured air Kerma were calculated. In addition was recorded the focal spot-to r distance, and the filter thickness. Monte Carlo methods were used to calculate the spectra, air Kerma, and Ambient dose equivalent for an X-ray tube (W target, Al2O3 filter) working to 40, 50, and 60 kV; these values and those previously reported were used to calculate the spectra mean energy, the air Kerma and the Ambient dose equivalent gamma factors in function of voltage. Mean values of measured voltage were used to calculate the gamma factors for air kerma and this with the current, and triggering time mean values, in addition to the focal spot-to-r distance, and the filter thickness were used to calculate the air Kerma. The relative difference between calculated air Kerma and the measured air Kerma varies from −6.84 to 10.82% at the Belen hospital, −2.22 to 9.64% at Las Mercedes hospital and from 0.41% to 6.30% at the Ferreñafe hospital; thus, calculated air Kerma values using the gamma factors were validated with measured air Kerma values. Air Kerma gamma factors can be used for dosimetric purposes using the operational features of the X-ray tube with W target and Al2O3 filter; in addition can be used during the design of primary barriers of radiology hall.