Table 2 Criteria for PET interpretation

Definition of a positive scan:

1. No uptake

Focal or diffuse FDG uptake above background in a location incompatible with normal physiology

2. Uptake ≤ mediastinum

Exceptions:

3. Uptake > mediastinum but ≤ liver

1.) Mild FDG uptake at the side of moderate to large residual masses with lower intensity visually compared to the mediastinal blood pool structures.

4. Uptake moderately > liver uptake, at any site

2.) FDG uptake in residual hepatic or splenic lesions should be compared to the uptake in surrounding normal liver or spleen

5. Markedly increased uptake at any site and new sites of disease.

A positive scan is usually interpreted as one showing areas of residual uptake with a score of ≥4, though criteria may vary