US 11,806,554 B2
Multi-channel real-time phase modulation for EMI reduction in an ultrasound device
Ron Kurtz, Oakville (CA); Patrick Leonard, Toronto (CA); and Xiaoyu Zhang, Mississauga (CA)
Assigned to Profound Medical Inc., Mississauga (CA)
Filed by Profound Medical Inc., Mississauga (CA)
Filed on Oct. 3, 2017, as Appl. No. 15/723,850.
Prior Publication US 2019/0099624 A1, Apr. 4, 2019
Int. Cl. A61N 7/02 (2006.01); A61N 7/00 (2006.01); A61B 90/00 (2016.01)
CPC A61N 7/02 (2013.01) [A61B 2090/374 (2016.02); A61N 2007/0078 (2013.01); A61N 2007/0095 (2013.01); A61N 2007/025 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method for reducing electromagnetic interference when operating an electrically-driven ultrasound thermal therapy apparatus, comprising:
positioning said apparatus including an ultrasound array of said apparatus with respect to a specified treatment zone;
in a computer-based host unit coupled to said therapy apparatus, determining a common driving frequency and determining an amplitude with which to drive each of a plurality of transducer elements of said array;
driving each of said plurality of transducer elements with a respective driving signal generated by a respective voltage source, the driving signal for each element comprising said common driving frequency, said amplitude, and a respective phase angle; and
modifying the phase angle of at least one driving signal to reduce a net electromagnetic output of said thermal therapy apparatus, wherein each phase angle is determined based, at least in part, on the amplitude of the corresponding driving signal,
wherein before modifying the phase angle of the at least one driving signal, the method further comprises:
(a) multiplying each amplitude and a respective phase offset value of +1 or −1 to determine a respective amplitude-phase product, each phase offset value representing a two-state phase assignment where +1 corresponds to a phase angle of 0 degrees and −1 corresponds to a phase angle of 180 degrees;
(b) summing the respective amplitude-phase products to calculate a residual Ri;
(c) repeating steps (a) and (b) for 2N-1 possible combinations of respective phase offset values to determine a plurality of residuals R2N-1 where N represents a number of the transducer elements in the transducer array; and
(d) comparing the residuals R2N-1 to determine a minimum residual Rmin;
wherein modifying the phase angle of the at least one driving signal comprises:
when the minimum residual Rmin equals 0, setting the respective phase angles according to the two-state phase assignment that corresponds to the minimum residual Rmin.