Analysis of Computed Tomography Derived Maps for Determining Changes of the Liver Volume After Exposure to Radiotherapy

1. Inclusion criteria:

   * Adults aged 18 years or older.
   * Received radiation therapy (RT) involving the liver (e.g., SBRT, IMRT). The study involves patients in whom the liver was exposed to radiotherapy, either as a direct target (in hepatic-directed treatments as in HCC or liver metastasis) or indirectly as an organ-at-risk (OAR) during irradiation of nearby anatomical regions (as lower lung, gastric, or abdominal sites) where the liver was partially included within the radiation field.

   The analysis aims to evaluate radiation-induced volumetric changes regardless of whether the liver was the primary target or secondarily affected.
   * Availability of paired pre- and post-RT CT scans of sufficient quality.
   * 3D dose distribution data from the RT treatment plan.
   * Clinical follow-up data, including liver function tests and toxicity records.
   * No evidence of major anatomical changes between scans unrelated to RT (e.g., surgery).
2. Exclusion criteria:

   * Patients with a history of major liver surgery (e.g., resection or transplant) between the pre- and post-RT scans.
   * Presence of severe motion artifacts or poor-quality CT scans that hinder accurate image analysis.
   * Incomplete or missing 3D radiation dose distribution data.
   * Lack of sufficient clinical follow-up information (e.g., liver function tests, toxicity outcomes).
   * Concurrent systemic therapies (e.g., chemotherapy or immunotherapy) during the imaging interval that may confound liver volume changes, unless controlled for in analysis.
   * Pre-existing liver conditions that could independently alter liver volume (e.g., cirrhosis, advanced hepatic steatosis) if not accounted for.
   * Patients under 18 years of age.