摘要： Magnetic resonance imaging (MRI) is an indispensable imaging tool in clinical diagnosis of a wide range of diseases, including cancer.[1] The resolution of MRI could be further enhanced by using the MR contrast agent. However, the most widely used MR contrast agents, gadolinium based contrast agents, show potential toxicity to human, which can induce serious side effects such as nephrogenic systemic ?brosis (NSF). Therefore, a biocompatible MR contrast agent with considerable contrasting effect is urgently needed to ensure the safety and clinical performance of this technique.[2] In this study, novel manganese based nanobubbles were fabricated to function as a T1 contrast agent for MRI. The nanobubbles were demonstrated to have good contrasting effect as well as very low toxicity. The major metabolic clearance of these nanobubbles in vivo was demonstrated in mouse model. We also demonstrated that our nanobubbles are perfect drug carrier for MR imaging-guided chemotherapy. Our results suggest that biocompatible manganese based nanobubbles are a promising MR contrast agent for clinical diagnosis and treatment of tumors.[3]