What is the term for the loss of concentration of a small object in an imaging system?

The term describing the loss of concentration of a small object in an imaging system is known as the Partial Volume Effect. This phenomenon occurs when a small object occupies a volume that is significantly smaller than the voxel size of the imaging system. As a result, the signal that represents that small object is diluted by the surrounding tissue or materials within the same voxel. This dilution leads to a loss of detail and accuracy in the image, making it difficult to distinguish small lesions or structures from the background.

In PET imaging, the Partial Volume Effect is particularly important because small tumors or abnormalities may not be accurately represented in the final images. This can lead to underestimation of their activity or size, affecting diagnosis and treatment planning. Understanding the Partial Volume Effect is critical for interpreting PET scans accurately and can help clinicians make informed decisions based on the imaging results.