“…Various heavy metal-based NPs have been investigated as potential CT contrast agents in pure metallic or chemical forms, including palladium (Pd, Z = 46) [24], silver (Ag, Z = 47) [25][26][27][28], cerium (Ce, Z = 58) [29,30], gadolinium (Gd, Z = 64) [31][32][33][34][35], dysprosium (Dy, Z = 66) [32,36,37], holmium (Ho, Z = 67) [37][38][39][40], ytterbium (Yb, Z = 70) [32,[41][42][43][44][45][46], tantalum (Ta, Z = 73) [32,[47][48][49][50], tungsten (W, Z = 74) [51][52][53][54][55], platinum (Pt, Z = 78) [56][57][58][59][60][61][62][63], gold (Au, Z = 79) [64][65][66][67]…”