Changes in Functional Liver Tissue After Liver Metastasis Irradiation: Pilot Study of Functional Imaging Before and After Stereotactic Body Radiotherapy

In this study, the investigators aim to determine the dose-effect relationship between radiation dose and liver function by performing a hepatobiliary scintigraphy (HEBIS) before and after stereotactic body radiotherapy (SBRT) for patients with liver metastases. HEBIS is a nuclear imaging technique to quantitatively assess liver function. It better predicts the risk of postsurgical liver failure compared to volumetry alone. To prevent liver failure after SBRT, current clinical dose constraints require that ≥ 700 ml of normal liver should receive less than 15 Gy in 3 fractions. The exact local dose-effect relation is however unknown. Doses below 15 Gy are still damaging, while liver tissue receiving doses above 15 Gy will retain some function. By associating the 3D radiation dose distribution with the HEBIS scan, the investigators can evaluate the impact of radiation dose on liver function for different dose levels in liver (sub)volumes. This analysis will refine existing dose-effect relationships, enabling more tailored treatment of liver metastases in the future. Ten to fifteen patients will be included to assess functional liver imaging using HEBIS before their treatment and 3 to 4 months after their treatment.