Rapid Cranial Contour Measurement Algorithm Based on Phased-Array Synthetic Aperture
Transcranial focused ultrasound technology as an emerging neuromodulation technology has been widely used in neuromodulation and treatment of the deep brain.The heteromorphism of the skull and the great variability of the acoustic parameters are the main reasons for the shift of the actual focal point and the scattering of the focal domain after the focused ultrasound penetrates the skull.In this study,based on the synthetic aperture technique,a phased array transmitted ultrasound signals and received the echo signals reflected from the inner and outer contours of the skull,and the coordinates of the skull contour points were simultaneously calculated to realize the rapid measurement of the skull contour.A real head simulation model and a skull simulation body were established to simulate and experimentally verify the algorithm.The simulation results showed that the maximum detection error of the outer contour center area of the skull model was 0.15 mm,and the edge area was 0.4 mm;the maximum detection error of the inner contour center area was 0.3 mm,and the edge area was 0.5 mm;the maximum detection error of the inner contour center area is 0.6 mm,and the maximum detection error of the inner contour center area was 0.6 mm,and the maximum detection error of the inner contour center area was 0.6 mm,and the maximum detection error of the inner contour center area was 0.6 mm,and the maximum detection error of the inner contour center area is 0.6 mm.The maximum detection error was 0.6 mm in the center of the inner contour and 0.9 mm in the edge area,and the rapid measurement algorithm designed in this paper was able to complete the accurate measurement of the inner and outer contour of the skull within 2 minutes,and controlled the maximum measurement error within 1 mm.Compared with magnetic resonance scanning(MRI)and electronic computed tomography(CT),it reduced the treatment cost and treatment time,and provided a new method and idea for the next step of adjusting the phased-array array element emission delay to realize real-time precise focusing in the skull.