The purpose of this study ass to investigate the addition of round 80-200m granules shape radiopaque agents (RA) to synthetic Injectable Bone Substitute to improve contrast performance for minimal invasive surgery MIS. Composites were obtained by mixing BaSO4, Bi2O3, Lu2O3 or GdPO4 with calcium deficient apatite CDA which decompose during sintering process in BCP (60% HA, 40% β-TCP). Each composite was characterized: by XRD, FTIR. Biocompatibility was tested in vitro and in vivo in bony site (3 weeks implantation in rats). Primary results show that the suitable radiopaque BCP/RA composite (radiopacity intensity, biological responses) appeared to be BCP/Ba. Next works will complete the current studies on biological performance in association with different kind of resorbable injectable bone substitute as suspension, gel or calcium phosphate cements.