Mieke Bus

43 3 non-invasive and invasive tumours and to differentiate between low- and high-grade lesions by quantifying µ oct . (34) Current commercial available OCT systems are limited to image lumina with a maximal diameter of 10 mm, compromising visualization of the pyelum as a whole. Furthermore, if tumour thickness transcends scattering-limited imaging depth in tissue (~2mm), invasive- ness cannot be assessed. detector mirror 1 Tissue (normal ureter) beamsplitter lightsource detector beamsplitter mirror 1 Figure 7: Optical Coherence Tomography, the optical equivalent of ultrasound imaging, measures light reflectivity vs. depth. It is based on white-light (large wavelength bandwidth) interferometry, where interference signals are only detected if the light in the sample and reference arm has travelled equal distances. Thus, by varying the length of the reference arm, the imaging location in the tissue can be controlled. Modern embodiments of OCT do not use moving reference mirrors; instead technical complexity is shifted toward either the light source (that sequentially provides each wavelength within the source bandwidth at high speed) or the detector (which detects each wavelength within the source bandwidth in parallel.