PERIMED's PeriScan PIM II and Moor Instruments' Moor Laser Doppler are highlighted in a discussion of the use of laser Doppler imaging in prediction of burn healing. Clinical strategies have demonstrated that laser Doppler imaging can correctly diagnose burn depth. However, surgeons are still doubtful that it is a must-have tool. At the Lillian B. Nanney at Vanderbilt University School of Medicine in Tennessee, strategies have shown that experienced surgeons misjudge burn depth between 30 percent and 70 percent of the time. New surgeons also may have difficulty in judging, but with laser Doppler imaging a more object method than viewing and touching may be possible. Laser Doppler methods rely on the principle that fixed and moving objects in tissue scatter coherent light. By detecting scattered light and with application of a math formula, movement of red blood cells, which is proportional to flow (tissue perfusion) can be determined. A spokesperson for Moor Instruments says the laser Doppler method is most dependable two to five days after a burn occurs because cell changes do not occur instantly. The Moor instrument uses a 780nm diode laser and generates a perfusion image with a resolution of 0.2mm per pixel at a speed of 4mx per pixel to a maximum of 256x256 pixels. The PeriScan PIM II uses a 670nm laser diode and is available in normal, high-resolution nonfocused laser, and high-resolution focused laser models.