Simulation of laser tomoscopy in a heterogeneous biological medium |
| |
Authors: | J M Maarek G Jarry J Crowe M -H Bui D Laurent |
| |
Institution: | (1) Laboratory of Physiology and INSERM Unit U. 138, Créteil Medical School, 8 rue du Général Sarrai, 94010 Creteil, France;(2) Bioengineering Unit, Department of Paediatrics, John Radcliffe Hospital, Headington, OX3 9DU Oxford, UK;(3) Laboratory of Physiology, Créteil Medical School, 8 rue du Général Sarrail, 94010 Créteil, France |
| |
Abstract: | A Monte Carlo model has been developed to study the propagation of an ultrashort light pulse through a heterogeneous thick
biological specimen. A circular blood vessel is moved within a tissular slab to simulate biological specimen scanning using
a picosecond laser source and a collimated ultrafast multichannel opticl shutter. Features of the transmitted light are computed
for each position of the blood vessel. The computer program gives an account of the transmitted photons, the flight time which
does not exceed straightforward crossing time plus time gate of known duration. A small blood vessel (radius R=2 mm) placed
in a 40 mm thick slab is easily located when a time gate of 10 ps duration is employed. Such a time gate also allows the detection
of a middle-sized vessel (R=4 mm) embedded in a thicker sample (80 mm). The contrast computed for the transmittance profile
is greatly improved when a time gate is used. In addition, shifting of the blood vessel towards the unilluminated side of
the sample decreases the contrast. We demonstrate that the time selection process may provide a substantial improvement to
the laser tomoscopy technique when used for imaging biological media. |
| |
Keywords: | Laser Monte Carlo method Time resolution Tomoscopy Transillumination |
本文献已被 SpringerLink 等数据库收录! |
|