Serial maximum intensity projection (MIP) PET images of mice injected with 52Mn-DOTA-TRC105 and 52MnCl2. Significant thyroid accumulation in the 52MnCl2 images contrasting the lack of uptake in the 52Mn-DOTA-TRC105 images indicates highly stable DOTA chelation of 52Mn2+ even at late time-points. Note: H, Heart; L, Liver; K, Kidneys; T, Tumor; Th, Thyroid.