
378 Second Harmonic Generation Imaging
16.2 Imaging Methods
16.2.1 Nonlinear Imaging Techniques for Collagen Characterization
Nonlinear optical imaging techniques, such as multiphoton laser scanning microscopy (MPLSM),
[29] are particularly useful for studying the changes taking place at the tumor−stroma boundary [30].
MPLSM is an optical sectioning technique that can simultaneously produce multiphoton excitation
(MPE) and second-harmonic generation (SHG). MPE occurs when two or more low-energy photons
excite a uorophore, which then emits a single photon with higher energy than the individual incident
photons [29,31] (Figure 16.3). ...