The Significant Values Of Applying MRI/CT/MSOT Triple-modal Imaging Contrast Agents In Accurate Diagnosis Of Breast Cancer

Breast cancer is one of the main malignant tumors that affecting female health worldwide.It's incidence currently ranks first in female malignant tumors in the whole world.The malignancy of breast cancer is not high,and most breast cancer patients can survive through conventional chemotherapy,surgical resection and other treatments.However,with the development of the society,women are increasingly demanding breast-conserving surgery and minimally invasive treatment.Precision medicine,with“precise diagnosis”and“precise treatment”as the main line,urgent needs“early discovery”and“early treatment”to extend the patient's life.Molecular imaging can show pathophysiological changes in the organism at the molecular or cellular level and diagnose cancers earlier.With the improvement of nanotechnology,nanomaterials have become a research hotspot in the field of biomedicine.Among them,composite magnetic nanomaterials have received extensive attention in biomedical fields due to their inherent magnetic properties,excellent chemical stability and good biosafety.Magnetic resonance imaging?MRI?,as one of the most important imaging techniques for breast cancer examination,provides high-resolution tissue and structural imaging information.However,it has problems such as long scanning time and low resolution.Computerized tomography?CT?imaging has the advantage of short scan time and low cost.Multispectral photoacoustic imaging?MSOT?has the advantages of high optical selectivity and deep penetration of ultrasound.Combining MRI,CT,and MSOT together could provide imaging results with fast,high-resolution,highly selective contrast.Therefore,the development of MRI,CT,MSOT multimodal image contrast agents has important application value in the accurate diagnosis of breast cancer.In this study,we designed and synthesized Au-Fe₂C magnetic nanoparticles.The superparamagnetic iron-carbon nanoparticle has the magnetic resonance T2 relaxation property.The strong absorption of the X-ray is achieved by coatining the heavy metal gold shell of the nanoparticle.The light absorption domain enables it to generate ultrasound signals for MRI,CT,and MSOT multimodal imaging.The size of the particles has been regulated to ensure passive targeting effect.By modifying the endogenous specific receptor ligand of HER2 on its surface,Au-Fe₂C-Z_HER2:342ER2:342 has the active targeting effect to HER2-positive breast cancer.Firstly,Au-Fe₂C magnetic nanoparticles were tested in vitro.The magnetic components of the material were used for MRI imaging after evaluating the T2relaxation performance and the optimal imaging concentration.CT values were evaluated by performing CT imaging on the absorption and attenuation characteristics of X-rays.MSOT capability weretested using its strong absorption peak in the near infrared spectral region.The composite nanomaterial can perform MRI/CT/MSOT triple-modal imaging,It plays an important role in early diagnosis and accurate diagnosis of tumor.Secondly,using Au-Fe₂C magnetic nanoparticles for in vivo-experiments.Mouse model of breast cancer tumors was first established.The Au-Fe₂C nanomaterials were injected into tumor-bearing mice by intravenous injection,and MRI images were performed at different time points.The distribution of Au-Fe₂C in tumors and organs of breast cancer model mice was observed and detected.Then CT imaging and multi-spectral photoacoustic imaging were performed to observe the distribution of nanomaterials in tumors.