With use of subpicosecond laser pulses, x-ray generation can occur with a smaller equivalent focal spot size than with conventional x-ray sources.

Surgical operations aiming at decreasing the Q-angle should be challenged.

The reproducibility of the rotation of the femur and the tibia and of the Q-angle was 2--3 degrees (SD) and of the patellar translation about 3 mm (SD). The result from the healthy volunteers will be a useful tool for evaluation of disorders in the knee joint.

The most important factor in reducing intra-observer variation was the ability to magnify (zoom) the images. The MATs also reduced variation. Filtering (edge enhancement), however, did not affect precision.

No abstract