title: Shear strain from irrotational tissue displacements near bubbles.
abstract: Particle displacements can be much greater near bubbles than they would be in a homogeneous liquid or tissue when exposed to an acoustic wave. In a plane wave, shear and bulk strains are of the same order of magnitude. In contrast, for a bubble oscillating close to its resonance frequency, the shear strain in the medium near the bubble is roughly four orders of magnitude greater than the bulk strain. This can lead to shear strains of a few percent even with acoustic excitation pressures far below the pressure thresholds required to cause inertial cavitation. High shear strains near oscillating bubbles could potentially be the cause of bioeffects. After acoustic exposures at audio frequencies, hemorrhages in tissues as diverse as lung, liver, and kidney have been observed at shear strains on the order of 1%.
authors.affiliation: Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627-0126, USA.
authors.forename: Edwin
authors.initials: E
authors.lastname: Carstensen
authors.forename: Sheryl M
authors.initials: SM
authors.lastname: Gracewski
authors.forename: Diane
authors.initials: D
authors.lastname: Dalecki
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005740:Gases; D006470:Hemorrhage / Q000473:pathology*; D007668:Kidney / Q000473:pathology*; D008099:Liver / Q000473:pathology*; D008168:Lung / Q000473:pathology*; D051379:Mice; D008962:Models, Theoretical; D009991:Oscillometry; D011312:Pressure; D013314:Stress, Mechanical; D013997:Time Factors; D014464:Ultrasonic Therapy
chemical_list: D005740:Gases
references.citation: J Acoust Soc Am. 2004 Feb;115(2):581-8
references.pmid: 15000170
references.citation: Ultrasound Med Biol. 1994;20(6):589-94
references.pmid: 7998379
references.citation: J Acoust Soc Am. 1986 Oct;80(4):1248-50
references.pmid: 3771931
references.citation: J Urol. 1990 Dec;144(6):1505-9
references.pmid: 2231957
references.citation: J Am Med Assoc. 1952 May 10;149(2):121-5
references.pmid: 14917570
references.citation: J Lithotr Stone Dis. 1991 Apr;3(2):147-56
references.pmid: 10149155
references.citation: J Acoust Soc Am. 2005 Mar;117(3 Pt 1):1440-7
references.pmid: 15807031