Spectral imaging applications

The fourth chapter by James McGuinty et al. describes the more advanced forms of time-domain FLIM. While not immediately available on commercial instruments this chapter should give the reader an idea what the current state-of-the-art is in terms of FLIM instrumentation, and perhaps what to expect on future commercial instruments. Real-time FLIM, combined FLIM-spectral imaging, hyperspectral FLIM-imaging, combined lifetime-anisotropy imaging and some of their applications are covered here. 

Zimmermann, T., Rietdorf, J. and Pepperkok, R. (2003). Spectral imaging and its applications in live cell microscopy. FEBS Lett. 546, 87-92. 

Ecker, R. C., de Martin, R., Steiner, G. E. and Schmid, J. A. (2004). Application of spectral imaging microscopy in cytomics and fluorescence resonance energy transfer (FRET) analysis. Cytometry A 59, 172-81. 

Bearman G.H., Levenson R.M., Cabib D. (Eds) Spectral Imaging Instrumentation, Applications, and Analysis, SPIE Publications, 2000. 

Vo-Dinh T., Cullum B., Kasili P., Development of a multi-spectral imaging system for medical applications, J. Phys. D-Appl. Phys. 2003 36 1663-1668. 

Spectral imaging is a complex and multidisciplinary field. The introduction of new FPAs is making it increasingly powerful and attractive. It has proven potential in qualitative pharmaceutical analysis and can be used when spatial information becomes relevant for an analytical application. Even if online applications and regulatory method validation require further study, the potential contribution of imaging to quality control and PAT needs no further demonstration. 

There are many potential applications in the commercial arena where NIR imaging can provide useful and unique information. The authors hope this overview of applications may help the reader determine whether or not NIR spectral imaging could be a viable approach to their particular problem. 

At present, two problems persist for the clinical application of IR spectral imaging methods. One of them is the enormous size of the datasets. In order to image an entire lymph node section, about 5x5 mm2 in size, on the order of 200 x 200, or 40000, individual spectra are collected. Although the data acquisition presents little problem and could be performed with existing array detector-based spectrometers within a few minutes, the data reduction by HCA takes over a day, even when using powerful personal computers such as the 64 bit AMD processor in our laboratory. The situation will undoubtedly improve tremendously when true 64 bit, WINDOWS-based operating system will be available to address the enormous... 

---