Fluorescence lifetime measurements with all-fiber optical setup for non-invasive in-vivo diagnostics

In this paper we present the possibilities of cheap diagnostics based on optical fiber sensors and fluorescence lifetime measurements. Early diagnostics of pathological tissue changes, especially when it comes to lesions that are possibly cancerous is still undiscovered for commercial use. Methods used nowadays, which are focused on scanning large areas of the human body (MRI, CT) are sensitive, yet they cannot determine whether the tumor is benign or malignant. Optical methods based on fluorescence are seeing more and more use, and eventually they may become a standard when it comes to fast and non-invasive medical diagnostics. We present a fluorescence lifetime measurements of cancerous and healthy human tissue performed with the use of a very simple optical fiber sensor. Results obtained on a standard fluorescent dyes (fluorescein in NaOH solution) show, that this setup was capable of measuring decay times of the nanosecond region, which is enough for most of the endogenous fluorophores of human body. Results obtained for human tissue show a difference between fluorescence lifetimes of healthy and cancerous human tissue. This a preliminary experiment, just to determine both spatial and time resolution of our setup, our primary goal is to perform such an examination during standard surgical procedure.