ABSTRACT
Evaluation of treatment response in oncology is very important in terms of patient management and modification of treatment protocols. Imaging parameters obtained from anatomical and molecular imaging modalities have an important role in predicting and monitoring treatment response, and can effect clinical decision-making processes in oncology. As a hybrid imaging modality developed in recent years, positron emission tomography/magnetic resonance imaging (PET/MRI) enables the anatomical evaluation of treatment response due to the high soft tissue contrast of MRI. Furthermore, the combination of metabolic/molecular information obtained from PET images with various functional parameters that can be obtained from multiparametric MRI provides complementary information about different features of tumor biology such as metabolism, cellular density and perfusion, and makes it possible to evaluate treatment response earlier than anatomical imaging. Previous studies show that PET/MRI has a serious potential in a more holistic assessment of treatment response and in predicting patient prognosis. Further multicenter and comparative studies with larger patient populations are necessary for examining the role of imaging parameters obtained from PET/MRI with F-18 fluorodeoxyglucose (FDG) or new molecular radiopharmaceuticals in evaluating the efficacy of different treatment modalities in various types of malignancies. In this review, it is aimed to evaluate the contribution of PET/MRI in therapy response assessment in oncological patients.