Imaging in oncology research

Imaging has been extensively used to monitor the development and progression of cancer in laboratory animals. Imaging also plays an increasing role in monitoring tumor response to therapeutic interventions. Using modern imaging technologies tumor volumes can be measured in subcutaneous and orthotopic models longitudinally. Furthermore, animals can be screened for the development and progression of metastases. Using imaging techniques it is also feasible to study non-invasively the microenviroment of tumor tissue, such as regional perfusion, vascular permeability, or oxygen tension. Depending on the specific scientific question, the tumor model and the location of disease, tumors are best studied by ultrasound, optical imaging, CT, MRI, SPECT, PET or a combination of these techniques. In this chapter we focus on techniques that have been used to study tumor localization and tumor mass, gene and protein expression, tumor microenvironment, tumor cell proliferation and metabolism and to monitor therapeutic interventions. The aim is to provide the reader an overview of the features of malignant tumors that can be studied on a routine basis in small animal imaging laboratories. Furthermore, practical guidelines for imaging protocols are provided and known pitfalls are discussed.