MB is also a moderate-strength fluorophore emitting at around 700nm in the near-infrared (NIR) even at a very low dose. Just in the last decade, researchers have started to use it in the NIR fluorescence clinical studies. In 2013, Alexander and his colleagues in Leiden University firstly studied the possibility of low-dose MB (0.5mg/kg) to identify parathyroid adenomas intraoperatively with the assistance of NIR fluorescence imaging system . 10 out of 12 patients have been histologically confirmed parathyroid adenoma, and 9 of 10 were clearly identified by MB NIR fluorescence, which is much better than the preoperative detection result (70%) of 99m Tc-sestamibi single photon emission CT (SPECT) scan. Another literature from Alexander demonstrated 10 out of 12 have been found parathyroid adenoma with fluorescence, and 6 normal parathyroid glands (median diameter 2.5mm) were also been detected in NIR fluorescence imaging, which were undetected otherwise . Detection of the small normal glands would be great beneficial to the cases in that subtotal resection of parathyroid glands is necessary, such as multiple endocrine neoplasia I syndrome . From 2014, a phase 1b, interventional study (NCT02089542) was carried out in UK involving 41 patients in order to develop a protocol of MB NIR fluorescence imaging in thyroid and/or parathyroid surgery with identifying the optimum dose of MB was 0.4mg/kg . And a phase II study of this protocol to evaluate clinical outcomes is expecting.