Using In Vivo Photoacoustic Flow Cytometry to Assess Circulating Tumor Cells in Melanoma

Abstract

Melanoma is widely metastatic at an early stage.  There is an increasing need to develop equipment that can detect circulating tumor cells (CTCs) faster than current assays, which often detect metastasis after it has spread to a fatal level.  Photoacoustic flow cytometry (PAFC) is based on nonradiative relaxation of absorbed laser energy into heat that produces an accompanying sound effect.  The photoacoustic (PA) detection of melanoma CTCs in current research was based on energy transformation from absorbance in melanin nanoparticles into heat which generated acoustic waves.  Evidence suggests that PA effects are more sensitive, have higher resolution, and can reach blood and lymph vessels at greater depths in vivo than current techniques.  Additional research could enhance these techniques, including development of high-speed PAFC, with the possibility of use in clinics and at home devices that could monitor CTCs in blood and lymph, potentially saving numerous lives.  Furthermore, flow cytometry has the potential to provide new therapy methods by laser ablation of cancer cells.