Fig. 4.

Example of SFDI instruments: (a) the working principle of the SFDI instrumentation is illustrated, including a light source, a projector, and a digital camera adapted from Ref. 1. Note that the simplicity of the imaging setup; (b) left and right: the reflect RS and Clarifi imaging systems, commercialized by Modulim; (c) the system developed at the Beth Israel Deaconess Medical Center that performed a first-in-human study during reconstructive surgery adapted from Ref. 14; (d) the system developed at the University of California Irvine that combines SFDI measurement with PDT treatment adapted from Ref. 15; and (e) endoscopic system developed at the University of Strasbourg, France, left: assembled, right: open.¹⁶