Optimal CT Protocols for CT-Guided Planning Preparation in Radiotherapy

The invention of the computed tomography (CT) in 1972 by Cormack and Hounsfield allowed for the very first time the acquisition of 3D images. CT scans taken for radiotherapy treatment planning usually differ from those taken for diagnostic use, since those are optimized to perform a three-dimensional dose calculation inside the patient. Radiation dose is of less concern than in diagnostic imaging, even though it should be always minimized. Image quality (IQ) has indeed relevant importance as it affects the accuracy of the treatment planning (par. 2). In order to correctly simulate a radiation treatment condition, several requirements are suggested: it is essentially the identification of the optimal CT acquisition parameter settings (CT scanner protocols), considering the special requirements of CT simulation (par. 3).