Table 1.

Criteria for an ideally effective clinical immuno-PET probe.

Number	Criteria
1	The physical half-life of the radionuclide needs to be compatible with the biological half-life of the linked antibody;
2	The target antigen should be significantly overexpressed in tumor tissues versus normal tissues;
3	The radiotracer targets tumor sensitively and specifically;
4	Rapid systemic clearance relative to the radionuclide half-life is critical to achieve high contrast imaging versus normal tissues;
5	Non-specific binding is minimal;
6	The radiotracer should be stable, so that unsafe radiometabolites are minimal and that the radionuclide remains sequestered relative to the effective half-life of the radiotracer;
7	Toxicity is low;
8	Preparation is simple and amenable to clinical radiopharmacies;
9	The radionuclide is readily available;
10	The radionuclide should have low positron energy and high positron (β+)-decay branch ratio or abundance;
11	Cost is low.