is ctdi patient dose
Computed tomography dose index. The computed tomography dose index (CTDI) is a commonly used radiation exposure index in X-ray computed tomography, first defined in 1981. The CTDI can be used in conjunction with patient size to estimate the absorbed dose. The CTDI and absorbed dose may differ by more than a factor of two for small patients such as children.
Dose Index (CTDI)â: CTDI is the equivalent of the dose. value inside the irradiated slice (beam) that would result. if the absorbed radiation dose profile were entirely concen-. trated to a rectangular profile of width equal to the nomi-. nal beam width NÂ·h.