Implementation of Polyvynil-Alcohol Mixed With Nano-Particles as a Near Representation of Biological Tissue: Ultrasonic and Photo- Thermal Study

Abstract

We present experimental results related to the manufacturing of phantoms based on polyvinyl-alcohol (PVA) mixedwith SiO2, graphite and Ag nanoparticles. These phantoms are dummy representations of the human tissue of thebreast gland. We focus our attention on the representation of the optical and the mechanical properties of the actualbiological healthy tissue and of that representing a hidden cancer tumor (lesion). The quality of the samples is testedby ultrasonic imaging and laser induced photothermal (PT) detection technique. From the former test, the mechanicalcontrast that one can achieve is apparent. Instead, the laser detection technique makes it possible to determine thatthe optical contrast is achievable. For the laser induced PT method we register the so-called photothermal amplitudes,rather known as photoacoustic (PA) signals. These are the ultimate expression of laser-induced bursts ofphotothermal processes, whose engine is the fraction of the optically absorbed energy that decays through nonradiativechannels. In our case we look for the conditions at which the PT phenomena are produced by a hiddendummy-tumor alone; meaning that the output signals are nearly free from substantial contributions from the bulk of thephantom. This is so as to mimic the actual mechanical and optical absorption performance of breast tissue with aninner cancer tumor. From the ultrasound images one can see how apparent the resemblance with the actual humantissue is.