Computed tomography for four‐dimensional dose calculation: Effect of detector array length

PURPOSE: Four-dimensional computed tomography (4DCT) is susceptible to a geometrical error when respiration changes upon patient shift. 4DCT using 16-cm detector arrays, not needing the shift, has been shown to improve geometrical accuracy, compared with a conventional 4DCT (4-cm array), albeit with some Hounsfield unit discrepancies. The 4DCTs were validated for 4D planning. MATERIALS AND METHODS: were additionally calculated on its phase images. The calculated doses were registered to the maximum-exhale image, and summed. RESULTS: with 62.76 Gy versus 62.76 ± 0.19 Gy for IMPT plans and 63.79 Gy versus 63.90 ± 0.28 Gy for VMAT plans. CONCLUSIONS: demonstrated accurate and reliable imaging of a lung tumor in 4D dose by IMPT plans. However, it could be affected by phase-sorting uncertainty.