What does the signal represent in tumor imaging?

In tumor imaging, the signal primarily represents the difference between the metabolic or physiological activity of the tumor compared to the surrounding normal tissue. This contrast is crucial because tumors often exhibit altered biochemistry, such as increased glucose metabolism, which can be detected by imaging modalities like PET. The ability to visualize this difference helps in identifying the presence of tumors, assessing their aggressiveness, and monitoring treatment response.

Understanding the nature of this signal is pivotal for clinicians as it aids in diagnostic processes and in planning further therapeutic interventions. The metabolic activity, visualized as a signal, is what distinguishes cancerous tissue from healthy tissue, thereby providing valuable information about the tumor's behavior and characteristics. This differentiation is essential for accurate assessment and management of cancer.