Motion Accuracy of Pneumatic Stepper Motor-Driven Robotic System Developed for MRI-Guided High-Intensity Focused Ultrasound Treatment of Prostate Disease

Table 4

RMSE of the offsets between the nominal and actual positions of the HIFU focal spots created in the BSA phantom.

Array	RMSE (mm)
	X-axis direction	Z-axis direction
3 × 3 array with 2-mm spacing	0.36	0.31
3 × 3 array with 3-mm spacing	0.53	0.19
5 × 5 array with 2-mm spacing	0.52	0.20