This indicates that CD64 imaging may be of complementary value to FOLRβ imaging for use in the clinic compared for which a [18F]fluoro-polyethylene glycol (PEG)-folate positron emission tomography (PET) tracer was developed and successfully used in arthritic rats [35] and human RA patients [36]. The gene discussed is FCGR1A; the disease is rheumatoid arthritis.