Evaluation of a high-speed multispectral light source for stroboscopic differential imaging for endocardial examination of Daphnia magna
In the field of medicine and biology there are fast repetitive movements at the microscopic level which influence the overall dynamics and behavior of the system. In order to present details of these fast movements which are above the temporal resolution limit of the human eye, a new stroboscopic multispectral imaging system was developed. The Daphnia magna, which is a good test organism due to its transparent shell, served as a test animal to evaluate this new imaging system. The heart rate of the Daphnia magna is about 400 beats per minute and thus the dynamics of the individual heart contractions of the animal can no longer be clearly differentiated using standard microscopy. These cardiac phases were visualized by stroboscopic illumination with pulse duration of 500 ns and with the aid of a microscope. The stroboscopic illumination was realized by a pulsed light source consisting of four light emitting diods (LED). In general, the spectral range of the illumination is configurable using combinations of these LEDs, however, in this instance the wavelengths were selected with the known absorption of haemoglobin at 410 nm, 470 nm, 680 nm and 870 nm. Furthermore, it was also possible to use the four wavelength differences available to generate images of Daphnia magna utilizing the transmission and absorption properties of biological tissue and its surrounding environment. In addition to a clear representation of the heart, the blood flow in the open cardiovascular system [1, 2, 3] of the Daphnia magna was imaged by observing the absorption of the macromolecule haemoglobin with different wavelengths.
Rogler, Georg N.