26 Bronchology – Past, Present and Future Diagnostic Procedures Documentation In the specially designed TELECAM^® SL-PDD camera system, the wavelength- dependent sensitivity was modified such that a high light transmission to the sensor chip is obtained in the fluorescence wavelength range in comparison to the sensitivity of a standard video camera. Both the light source and the video camera  are  equipped  with  a  fluorescence  mode  (blue  light  mode  AF/ALA). During observation, the operator can easily switch between white light or blue light mode either by means of a push-button on the camera head or by a foot switch directly connected to the D-LIGHT AF light source. Observations can be documented on a monitor, video screen or printed out. Normal mucosa is dominated by homogenous green fluorescence. There is a three-dimensional  effect  showing  cartilage,  blood  vessels  and  membranes along with the muscular striations. The malignant tissue shows a rusty brown color or bluish discoloration. Experience is required to interpret normal variations and different pathological phenomena of the bronchial anatomy as revealed by fluorescence. Autofluo- rescence shall unfold new dimensions in the future. It is advisable to observe the larynx and vocal cords in autofluorescence mode while withdrawing the instrument. 4.  Fluorescence System KARL STORZ D-LIGHT AF, using Filtered Xenon Light, Direct Imaging Technique. With administration of 5-ALA. This system is incorporated in the KARL STORZ D-LIGHT AF system. It uses 5-aminolevulinic acid (hydrochloride) (5-ALA), an endogenous substance and the starting product of the intracellular heme biosynthesis pathway. ALA is formed from Succinyl CoA, which is an intermediate of the citrate cycle, and used in the next to last reaction step, in which protoporphyrine IX (PPIX) is generated.  PPIX  is  fluorescent  and  selectively  accumulates  in  tumor  cells. Within a short period of time, the concentration of PPIX is sufficiently high for xenofluorescence on excitation. No toxic or side effects have been observed to date after the administration of 5-ALA by aerosol inhalation before examination. A 300 W Xenon short-arc lamp emits blue light in the wavelength range of 380 – 440 nm. Light emission can be switched from white light to blue-violet (and vice versa) for fluorescence excitation. An observation filter inserted in the obser- vation pathway reduces the blue portion of the fluorescence excitation light, transmitting only a small fraction of 2%. This light intensifies the color contrast between the red fluorescent and non-fluorescent areas. Tumors and pre-malig- nant  areas  are  well  demarcated  in  red.  PPIX  shows  an  absorption  around 410 nm and fluorescence with a broad peak at 635–705 nm. a b c Back –––––––Table of Contents–––––––Next Back –––––––Table of Contents–––––––Next