Margin reduction and optimal prescription isodose model for liver stereotactic radiotherapy with respiratory motion

The proposed v4DCT-based framework demonstrated that the 60% isodose plan provided the optimal balance between tumor coverage and normal-tissue sparing, yielding an OM of 5.6 mm (44% reduction compared with the conventional 10-mm PTV). This approach offers a clinically applicable strategy for margin reduction in liver SBRT while maintaining robust dosimetric coverage.