Characterization of radiation qualities used for the determination of characteristic in CT application according to IEC 61267:2005

The purpose of this study was to establish the standard RQT radiation qualities which represent simulations of the unattenuated beam used in Computed Tomography (CT). Thus, to avoiding excessive efforts for establishing a radiation quality by means of the spectral distribution of the photon fluence, the characterization of these standard radiation qualities was expressed in terms of the X-ray tube voltage, first and second half-value layer (HVL). To establishing the standard radiation beam, according to the IEC 61267 and the TRS 457 was measured first of all the correct values of the X ray tube voltages in terms of Practical Peak Voltage. The standard radiation qualities RQT were produced using the same set up mounted for the RQR qualities which had been early established, and for simulating the patient in order to achieve the standard RQT series, suitable thicknesses of layers of copper were used to obtain the values of the first HVL according to IEC 61267. (author)