The study of photoacoustic imaging without nanoparticles as a contrast agent for anti-body drug monitoring

As an emerging hybrid Imaging, Photoacoustic became a powerful tool that can scan disease at the deeper site in tissue and monitor of drug delivery in vivo. PAI system used nano-particle as contrast agent to enhance the PA signal in deeper site in tissue. So this makes that PAI's application have some limitation for monitoring of all kinds of anti-body drug, because of various anti-body's absorption excitation. In this study, we designed a PAI system with a tunable pulse OPO laser (from 450 similar to 700nm excitation wavelength) to show the optimal wavelength for monitoring of the antibody drug; doxorubicin having peak absorption at near 500nm excitation without any nano-particle combine. We made a gelatin phantoms having 4 different concentration doxorubicin as an anti-body drug; Doxorubicin concentration were in 0mg/ml, 0.5mg/ml, 1mg/ml, and 2mg/ml. We found that 500nm is optimization wavelength to produce PA peak signal and PAI can be tool to monitor of anti-body drug without contrast agent.