title: Evidence for free radicals produced in aqueous solutions by diagnostic ultrasound.
abstract: Recent theoretical calculations have shown that small gas nuclei in water exposed to microsecond ultrasonic pulses above an intensity threshold may grow into transient cavities that collapse violently, leading to the formation of .OH radicals and .H atoms. We have detected these free radicals in aqueous solutions exposed to microsecond pulsed ultrasound using spin trapping and electron spin resonance (ESR). The public health implications of our results are discussed.
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006859:Hydrogen / Q000032:analysis; D006878:Hydroxides / Q000032:analysis; D017665:Hydroxyl Radical; D066298:In Vitro Techniques; D012996:Solutions; D013997:Time Factors; D014463:Ultrasonography / Q000009:adverse effects; D014867:Water / Q000528:radiation effects*
chemical_list: D005609:Free Radicals; D006878:Hydroxides; D012996:Solutions; D014867:Water; D017665:Hydroxyl Radical; D006859:Hydrogen