Five young healthy subjects will be participated in Whole-body positron emission tomography /computed tomographic (PET/CT) scans from the midfemoral position to the head after approximately 5-10 mCi of SNUBH-NM-333(18F) injection. For brain PET/CT amyloid imaging, another five young healthy subjects will be scanned dynamically during windows of 0-180 min after injection of SNUBH-NM-333(18F), with arterial sampling.