What is ratiometric imaging?

Ratiometric imaging is a technique used to analyze ion concentrations by measuring fluorophore shifts. It involves the use of ratiometric indicators, a specific type of dual wavelength fluorescent dye that show a shift in their emission or excitation spectra when on binding to calcium. These dual wavelength ion indicators enable researchers to measure the intensities at two or more wavelengths of an excitation or emission spectrum in order to detect changes to the local environment. Among ratiometric calcium indicators, Fura-2 and Indo-1 are the most widely used.