The use of respiratory-correlated four-dimensional CT where kidney motion has the potential to impact upon the radiotherapy planning process.

Purpose: Four-dimensional CT (4D-CT) image data can be sorted into bins of each 10% of the respiratory cycle. From these data, an averaged scan (AS) and a maximum intensity projection (MIP) are derived. While sorting based on the respiratory cycle applies to lung tumours, the use of 4D-CT for the kidney has not been analysed.