Hypoxia is a state of reduced oxygenation in tissue and is the most widely studied of all the microenvironmental changes. Regardless of the level of perfusion or status of the vasculature in a tumor, hypoxia induces changes that reflect homeostatic attempts to maintain adequate oxygenation by increasing 02 extraction from blood and by inducing cells to adapt by developing more aggressive survival traits through expression of new proteins. Angiogenesis is the formation of new blood vessels and is also an important attribute in a number of physiological processes vital for sustaining cancer cells and promoting tumor growth. It is critical for delivering nutrients for tumor growth and in providing energy to support invasion and metastatic spread. Clinical hypoxia imaging using FMISO and Cu-ATSM are in advanced stages of clinical experience. Optimal characterization of therapeutic targets is essential for the development and clinical evaluation of novel drugs targeting angiogenesis and hypoxia. Hypoxia imaging provides information that is different from that of FDG-PET and should play a pivotal role in oncologic imaging. Among all the hypoxia imaging radiopharmaceuticals, Cu-ATSM images show the best contrast early after injection, but these images are confounded by blood flow. The greatest advantage of PET/CT imaging will be the improved accuracy in localizing hypoxia and making it possible to incorporate these images into radiation treatment planning systems to safely plan and deliver a hypoxia-directed radiotherapy boost using intensity-modulated radiation therapy within the framework of radiobiological rationale.
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging