Among patients undergoing angioplasty there is a chance that about 30% will develop restenosis with 6 months following the procedure. In these patients, a short period after the procedure, activated macrophages and lymphocytes are present in the neointima.
The research hypothesis was:
If these lymphocytes and macrophages could be detected at that time, then treatment can be applied.
In order to detect these "biological markers" one should develop a fluorescent marker that can tag them specifically and then can be detected by an optical imaging system.
Our first setup was a fluorescence detection system based on Argon laser (wavelength - 488 nm), fluorescence camera, Spectrophotometer, filters and optical devices. This system was designed to look at fluorecein based markers which are bio compatible and commonly used in some medical applications (i.e. ophthalmology). We have conducted some experiments on tissue like phantoms, which were prepared in our laboratory. Our experiments have proved our concept and allowed us to move into the IR spectral region in order to be able to look deeper in tissue. This was possible due to the enormous development of molecular biology and the introduction of new fluorescent dyes. In this system we are using NIR dyes (ird 38 AND ird 41). Our exciting laser is a diode laser at 787 nm. The diodes are current and temperature controlled for fine tuning and wavelength stability. In order to quantify the amount of the fluorescent markers and their location we are developing algorithms, which will reconstruct from 2-D fluorescent images the location and concentrations of the markers. The algorithms take into account also the blood flow in the suspected area.
