Figure 5
Validation of the motion compensation (MoCo) method in phantom scans. (a) The time series of 31P spectra acquired while the patient table was moved shows little fluctuations when the voxel position was updated prospectively using the proposed image-based navigation. (b) Illustration of the motion of the measured phantom (d = 20 mm), the voxel position along the z-axis with (blue) and without (orange) motion compensation and the measured signal amplitude when using motion compensation. The signal amplitude is preserved even when the target (sphere) is moved entirely from its initial position. (c) Using the motion phantom20 and the external MPT motion tracking system7 to confirm the correct tracking, combination and position update of the MoCo method. Image acquisition (\(2 \times\) 114 ms) and processing (< 40 ms) induced a latency of less than 300 ms, as visible from the two position traces in the inset. (d) The signal gain with MoCo (blue) compared to without MoCo (orange) is apparent in the spectral data of these time series.
