ABSTRACT
Molecular imaging, also referred to as biological imaging or functional imaging, is the use of non-invasive imaging techniques that enable the visualization of various biological pathways and physiological characteristics of tumours and/or normal tissues. In short, it mainly refers (but not only) to positron emission tomography and magnetic resonance imaging. In clinical oncology, molecular imaging offers the unique opportunity to allow an earlier diagnosis and staging of the disease, to contribute to the selection and delineation of the optimal target volumes before and during (i.e. adaptive treatment) radiotherapy and to a lesser extent before surgery, to monitor the response early on during the treatment or after its completion, and to help in the early detection of recurrence. From the viewpoint of experimental radiation oncology, molecular imaging may bridge radiobiological concepts such as tumour hypoxia, tumour proliferation, tumour stem cell density and tumour radiosensitivity by integrating tumour biological heterogeneity into the treatment planning equation. From the viewpoint of experimental oncology, molecular imaging may also facilitate and speed up the process of drug development by allowing faster and cheaper pharmacokinetic and biodistribution studies.
