Feasibility study of in vivo MRI based dosimetric verification of proton end-of-range for liver cancer patients.

Purpose: To investigate the feasibility of using MRI to verify proton beam distal range for liver tumor treatment in a retrospective study.

Methods And Materials: Because the follow-up hepatocyte-specific functional MR imaging can detect the radiobiological change of liver tissue after radiation, we firstly registered the contrast-enhanced MR images to the planning CT images from 5 liver patients, then overlaid the prescribed dose distribution on the MR images. Since dose calculation is most accurate at the penumbra dose region, we correlated the MR signal intensity (SI) to the radiation dose at the superior/inferior penumbra region.

An analytical solution to proton Bragg peak deflection in a magnetic field.

The role of MR imaging for image-guided radiation therapy (IGRT) is becoming more and more important thanks to the excellent soft tissue contrast offered by MRI. Hybrid therapy devices with integrated MRI scanners are under active development for x-ray therapy. The combination of proton therapy with MRI imaging has only been investigated at the theoretical or conceptual level.