Prussian blue (PB), a kind of ferrous ferricyanide composed of Fe2+ and Fe3+, has been approved by Food and Drug Administration (FDA, USA) as an oral drug for the treatment of thallium and cesium poisoning. The biosafety of PB has been proved by long-term clinical trials. In recent years, PB nano-materials have attracted intensive research interests for medical application, especially for tumor imaging and treatment of cancer. Compared to other nano-materials, PB has potential advantage in medical application due to the high biosafety. This paper reviews the new advances in the functions of cancer diagnosis and therapy of PB nano-materials.
Acoustic resolution photoacoustic microscopy (ARPAM) combines the advantages of high optical contrast, and high ultrasonic spatial resolution and penetration. However, in photoacoustic microscopy (PAM), the information from deep regions can be greatly affected by the shallow targets, and most importantly, the irreconcilable conflict between the lateral resolution and depth of fields has always be a major factor that limits the imaging quality. In this work, an ARPAM system was developed, in which a non-coaxial arrangement of light illumination and acoustic detection was adopted to alleviate the influence of the tissue surface on the deep targets, and a novel focal zone integral algorithm was applied with multiple axial scanning to improve the lateral resolution. Phantom experiment results show that, the build system can maintain a consistent high lateral resolution of 0.6 mm over a large range in axial direction, which is close to the theoretical calculations. The following tumor imaging results on nude mice indicate that, the proposed method can provide more in-depth information compared with the conventional back detection ARPAM method. With the development of fast repetition lasers and image scanning technologies, the proposed method may play an important role in cerebral vascular imaging, cervical cancer photoacoustic endoscopic detection, and superficial tumor imaging.