CT Dose Index Test with Standard Phantoms

摘要

The aim of the study was to find out how the measured absorbed dose by using standard dose test method (with CT dose head and body phantoms) depends on the different axial scanning technologies and how they affect the measured value.The results show that using pencil type ionization chamber the measured absorbed dose distribution which determines value of CT dose index (CTDI_(100)) is not equable across the ionization chambers.Uncertainty can reach 30 - 35% of the value during dose measurements of 100 mm long part of the head phantom and up to 50% of the value during measurements of the same length body phantom. It is considered that 5% uncertainty is acceptable during dose measurements in the 40 mm middle range of head phantom and 45 mm in the middle of the range in body phantom.