There are two aspects to dose delivery. First, the physical amount of dose and, secondly, is it in the correct position. Both aspects are significant and, in addition to safety systems, are the key to satisfactory radiotherapy performance.
When we consider the many and various components within the radiotherapy process, these two aspects are identifiable as where uncertainty in the treatment delivery can occur. For example, the calibration of CT number for dose prediction is a dose aspect while the movement accuracy of the scanner and processing of the image matrix will be a positional aspect.