Radiation dosimetry descriptors applied to four CT scanners in New Zealand

Doses to patients have been estimated for the four New Zealand CT Scanners, in terms of recently proposed dose descriptors. These descriptors were computed tomography dose index, multiple scan average dose, equivalent rectangular width, a figure of merit, and integral dose. X-ray beam dose profiles, half-value-layer and peak kilovoltage were also determined. Dosimetry was by thermoluminescent dosimeters, pencil ionization chamber, and x-ray films, in cylindrical solid perspex phantoms. The four scanners were all found to give comparable doses to patients