ALB and neoplasm: Although the prolonged tumor retention of IR-786©BSA is still unclear, it was explained that heptamethine cyanine dyes with a meso-chloride (i.e., IR-780 and IR-783) tend to be much longer living in tumors than heptamethine cyanine dyes without a meso-chloride (i.e., ICG), owing to the difference in covalent or noncovalent binding to albumin [17].