title: Radiation-force technique to monitor lesions during ultrasonic therapy.
abstract: This report describes a monitoring technique for high-intensity focused ultrasound (US), or HIFU, lesions, including protein-denaturing lesions (PDLs) and those made for noninvasive cardiac therapy and tumor treatment in the eye, liver and other organs. Designed to sense the increased stiffness of a HIFU lesion, this technique uniquely utilizes the radiation force of the therapeutic US beam as an elastographic push to detect relative stiffness changes. Feasibility was demonstrated with computer simulations (treating acoustically induced displacements, concomitant heating, and US displacement-estimation algorithms) and pilot in vitro experimental studies, which agree qualitatively in differentiating HIFU lesions from normal tissue. Detectable motion can be induced by a single 5 ms push with temperatures well below those needed to form a lesion. Conversely, because the characteristic heat diffusion time is much longer than the characteristic relaxation time following a push, properly timed multiple therapy pulses will form lesions while providing precise control during therapy.
authors.affiliation: Biomedical Engineering Laboratories, Riverside Research Institute, New York, NY 10038, USA.
authors.forename: Frederic L
authors.initials: FL
authors.lastname: Lizzi
authors.forename: Robert
authors.initials: R
authors.lastname: Muratore
authors.forename: Cheri X
authors.initials: CX
authors.lastname: Deng
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Ketterling
authors.forename: S Kaisar
authors.initials: SK
authors.lastname: Alam
authors.forename: Samuel
authors.initials: S
authors.lastname: Mikaelian
authors.forename: Andrew
authors.initials: A
authors.lastname: Kalisz
mesh_terms: D000818:Animals; D002417:Cattle; D003198:Computer Simulation; D004548:Elasticity; D005240:Feasibility Studies; D006358:Hot Temperature; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000000981:diagnostic imaging; D009038:Motion; D019047:Phantoms, Imaging; D011489:Protein Denaturation; D014159:Transducers; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography