Dosimetric comparison of liver tumour radiotherapy in all respiratory phases and in one phase using 4DCT

Gated radiotherapy could potentially allow a reduction in PTV volumes from those delineated on all respiratory phases, maintaining acceptable target coverage. Smaller target volumes improve doses distribution in normal tissue especially in the liver and kidney, but also spinal cord and intestine. A significant correlation has been found between dose and volume reduction in the OARs and both GTV motion and PTV volume reduction.