Interestingly, in NHL [14], where the 18F-FSPG retention was variable between patients, Ki67 staining for the patient with mantle cell lymphoma with low 18F-FSPG retention was 6%, while for the second patient with high 18F-FSPG retention (nearly double the comparative 18F-FDG retention), Ki67 was 20%. Here, MKI67 is linked to mantle cell lymphoma.