Fig. 3.

Processing of the SG signals from a “SPACE SWL+SG” scan in a healthy volunteer illustrates how the SG method detects swallowing motion. The time courses of projection profiles (a. and c.) and cross-correlation coefficients (CC) (b. and d.) obtained from SG₁ and SG₂, respectively, clearly demonstrates that instructed swallowing events are always detected by either or both of the two SG signals. In contrast to the projection profiles devoid of motion, motion-contaminated projection profiles deviate substantially in shape and magnitude from the reference projection profile (e.).