Currently, early diagnosis and treatment of cancer remain one of the medical challenges due to the lack of highly sensitive diagnostic methods and effective means. The rapid development of molecular imaging and chemical/genetic therapies, especially the organic combination of nuclear magnetic resonance imaging and drug/gene therapy, has given rise to the idea of integrated cancer diagnosis and treatment. There are still many problems in current research on cancer diagnosis and treatment, such as insufficient sensitivity of contrast agents, poor water solubility of drugs, short circulation time, weak targeting, significant toxic side effects on normal tissues and cells, and poor biodegradability of carriers. Amphiphilic block copolymers self-assembled into multifunctional polymer nanovesicles offer a new approach that is expected to solve these problems, thereby achieving targeted diagnosis and drug delivery for cancer, and ultimately realizing the integration of cancer diagnosis and treatment. This system is based on degradable polymers. It has good biocompatibility and degradability, and can be broken down into small molecules by enzymatic action for metabolism and absorption by the body. Its RL relaxation rate is as high as 42.39, which is 9-10 times that of small molecule contrast agents. In this case, the injection dose can be significantly reduced, and the toxicity of the contrast agent can be alleviated. At the same time, by observing the magnetic resonance imaging effect in tumor-bearing mice through tail vein injection, 15 minutes after the injection, the MRI signal within the mouse's blood vessels was significantly enhanced, and there was also a strong signal near the tumor site. However, due to insufficient blood supply within solid tumors, it is difficult for magnetic resonance imaging effects to occur, resulting in poor signal at the tumor site. After 60 minutes of injection, the signal intensity around the tumor site was significantly enhanced, with vascular signals included, and signals appeared in organs such as kidneys, liver, and bladder, indicating that the contrast agent accumulated in these organs and could eventually be excreted from the body through glomerular filtration. In addition, this polymer nanomaterial can also target the efficient delivery of chemotherapy drugs and is an excellent diagnostic and therapeutic integrated material. The material uses a degradable polymer system, with an r2 value reaching 611, which is the highest reported for magnetic resonance imaging contrast agents carried by polymer micelles or vesicles. Imaging results in tumor-bearing nude mice show that after intravenous injection into the tail vein, due to the characteristics of negative contrast agents and folate targeting, the contrast effect at the tumor site gradually increases, allowing for the differentiation of diseased tissue from normal cells through T2 imaging. The image above is a photo of a tumor-bearing mouse, showing that after 24 days using iron-carrying polymer vesicles for T2 imaging, the tumor tissue has been controlled, with a significant reduction in volume, proving its practicality.