Nuclear Medicine & Radiation Therapy

Imaging Tumor Response to Radiation Therapy in Liver

Abstract

Hesheng Wang

Currently, there are increasing interests in imaging tumor response to radiation therapy (RT) of hepatic cancer. Early detection of tumor response may allow a change in the treatment before completion of the prescribed therapy and maximize therapeutic efficacy of the treatment. Most importantly, once early tumor response indicates achievement of final tumor control, withholding treatment will prevent radiationinduced diseases. Response Evaluation Criteria in Solid Tumors (RECIST) which evaluates tumor response based on change in tumor size is a clinically adopted approach to determine solid tumor responses. But it may take several weeks for RECIST criteria to suggest success or failure of a treatment, which may lead to severe radiation toxicity or tumor progression due to inadequate radiation delivery. Advances of medical imaging allow high-sensitivity and high-specificity assessment of tumor biological process and, therefore, may provide surrogates of tumor response before morphological change occurs.