[Preclinical imaging in animal models of radiation therapy].

CLINICAL/METHODICAL ISSUE: Modern radiotherapy benefits from precise and targeted diagnostic and pretherapeutic imaging. STANDARD RADIOLOGICAL
METHODS: Standard imaging modalities, such as computed tomography (CT) offer high morphological detail but only limited functional information on tumors. METHODICAL INNOVATIONS: Novel functional and molecular imaging modalities provide biological information about tumors in addition to detailed morphological information. PERFORMANCE: Perfusion magnetic resonance imaging (MRI) CT or ultrasound-based perfusion imaging as well as hybrid modalities, such as positron emission tomography (PET) CT or MRI-PET have the potential to identify and precisely delineate viable and/or perfused tumor areas, enabling optimization of targeted radiotherapy. Functional information on tissue microcirculation and/or glucose metabolism allow a more precise definition and treatment of tumors while reducing the radiation dose and sparing the surrounding healthy tissue. ACHIEVEMENTS: In the development of new imaging methods for planning individualized radiotherapy, preclinical imaging and research plays a pivotal role, as the value of multimodality imaging can only be assessed, tested and adequately developed in a preclinical setting, i.e. in animal tumor models. PRACTICAL RECOMMENDATIONS: New functional imaging modalities will play an increasing role for the surveillance of early treatment response during radiation therapy and in the assessment of the potential value of new combination therapies (e.g. combining anti-angiogenic drugs with radiotherapy).