Quantitative fluorescence is the exhibition of radiation emitted in a specimen. Using imaging technology, a scientist can collect information about the specimen and use it to learn more about its structure or function. This approach is commonly used in biology to study individual cells and whole organisms. It requires access to a lab that contains microscopy equipment and cameras of appropriate sensitivity. Examples of images from this form of analysis can be seen in textbooks and scientific papers, along with discussions of the data obtained.
Specimens prepared for microscope imaging can be stained with fluorescent tags, like proteins that attach to specific structures in the cell. When these tags are viewed through a camera in the right conditions, they light up. Simply observing the illumination can provide important information for the researcher. For example, an immunologist looking for traces of a specific antibody could use a tag to identify it. This is an example of qualitative fluorescence, where the illumination provides general information about the qualities of the specimen.
In measurements of quantitative fluorescence, the researcher collects specific, measurable information. This could include data about the precise intensity of the light. Further treatment of the specimen can offer opportunities for advanced imaging techniques like Fluorescent Recovery After Photobleaching (FRAP), which provides information about the movement of structures inside specimens. All of these quantitative fluorescence techniques can offer new insight into what a structure is, how it functions, and what it contains.
Precision equipment is required for this type of work. Any fluorescent treatments added to a specimen need to be carefully prepared so they tag the desired structures and nothing else. The equipment needs to be appropriately sensitive, and calibrated to confirm it is picking up accurate information. If the detector in a digital camera is off, for example, it may fail to collect fluorescence in some parts of the specimen, or could generate a false reading. In both cases, the data would be incorrect.
Pathology labs may use quantitative fluorescence for the evaluation of some specimens. This technique is also widely used in research. Some very striking images can be developed with the assistance of fluorescent tags to separate out structures like nerves or specific proteins. In addition to being visually remarkable, the images can contain a wealth of information for researchers with the capability of reading them. It is possible to analyze quantitative fluorescence images with advanced computer programs to extract more data and generate meaningful results.