Stereotactic ablative body radiotherapy (SABR) is a highly focused type of radiotherapy that can be very effective for treating small liver cancers (hepatocellular carcinoma or HCC) that cannot be removed with surgery. It achieves good control of the cancer in many people, with success rates of around 68–95% after three years.

However, SABR must be used carefully because it can sometimes cause a condition called Radiation‑Induced Liver Disease (RILD). This is more likely to happen in people with HCC because many already have cirrhosis or reduced liver function, meaning the liver has less ability to cope with radiation.

One way to make SABR safer is to understand how well different parts of the liver are working. Standard scans show the shape of the liver, but they do not show how healthy each area is. Some types of scans can show liver function, but they use contrast dye or radiation, so they can’t be done very often.

This study is looking at a new type of MRI scan that does not require contrast dye. We want to see if this scan can help us:

• Plan SABR treatment more safely by protecting the healthiest parts of the liver
• Monitor how the liver responds to treatment

If we can better protect the well‑functioning parts of the liver, we may be able to reduce the risk of RILD and possibly give higher treatment doses when needed, which may improve cancer control.

If you choose to join this study:

• You will have an MRI scan after your radiotherapy planning CT scan
• You will have a second MRI scan shortly after your final SABR treatment
• There are no additional follow‑up visits required for this study

These scans are used only for research purposes and will not affect your planned cancer treatment.