Study of Radiation Dose and Device Quality for Diagnostic X-ray Units

Abstract

Digital kVp meter, ion chamber, and x-ray films were used to study the tube voltage, beam output, and dose distribution for 29 x-ray units. Of which 14 units are equipped with single phase power supply and 15 with inverter frequency power supply. The experimental results show that the dose is dependent on tube voltage, tube current, field size except beyond 20×20cm², exposure distance, and heel effect. The relationship between dose and tube voltage and exposure distance as well is non-linear, while that between dose and tube current is linear. The non-uniform and non-symmetric dose distribution depends on the heel effect of the x-ray beam. The measured voltage deviating from the default value may reach -2.4% to -9.1% depending on the power supply system used. The dose delivered from the units with inverter frequency power supply is 1.64 times higher than that with single phase power supply.