Mieke Bus

38 Chapter 3 Light source Detector Wavelength Filter 540 nm scope 415 nm A B Figure 3: Narrow-band imaging is based on the phenomenon that the depth of light penetration increases with wavelength. Tissue is illuminated with light centred on 415 nm (blue) and 540 nm (green), which are both absorbed by haemoglobin more strongly than other tissue. The blue light enhances the superficial capillary network, whereas the green light enhances the visibility of deeper vessels. (WL: white light (A). NBI: narrow band imaging (B)) Storz Professional Image Enhancement System A new technology using spectral separation is recently introduced called Storz Professional Image Enhancement System (SPIES®) (Table 1). White light images are acquired with a RGB camera, after which several different digital imaging modes can be used to modify the dis- played image (Figure 4). The system comprises of two modes (SPECTRA A/B), which pro- nounce the imaging spectral separation via different colour renderings, highlighting the contrast between different tissues and structures. A third mode (CLARA) uses a local bright- ness adaptation to achieve clearer visibility of darker regions within the image and a fourth mode (CHROMA) enhances the structures within the displayed image via an increased colour contrast. The clinical value of SPIES is currently under investigation and no clinical data of the upper urinary tract are yet available.