Tumour motion analysis from planning to end of treatment course for a large cohort of peripheral lung SBRT targets

The aim is to quantify and analyse tumour motion during a course of treatment for lung SBRT patients. Peak-to-peak motion of 483 tumours in 441 patients treated with peripheral lung SBRT at a single institution over a two year period was measured on planning CT and at all treatment fractions. Planning 4D-CT scans were analysed using our clinical workflow involving deformable propagation of the delineated target to all phases. Similarly, acquisition of the 4D-CBCT data followed the clinical workflow based on XVI 5.0 available on Elekta linacs. Differences and correlations of the peak-to-peak motion on the planning CT and at treatment were analysed. On the planning CT, a total of 81.4% of the tumours had a peak-to-peak motion