title: Single-particle optical sizing of microbubbles.
abstract: Single-particle optical sizing techniques are being used to determine the size distributions of microbubble ultrasound contrast agents and to study the dynamics of individual microbubbles during ultrasound stimulation. The goal of this study was to compare experimental light obscuration and scattering measurements of microbubble size distributions with predictions from generalized Lorenz-Mie scattering theory (GLMT). First, we illustrate that a mono-modal size distribution can be misrepresented by single-particle light obscuration measurements as multi-modal peaks because of non-linearities in the extinction cross section-versus-diameter curve. Next, polymer bead standards are measured to provide conversion factors between GLMT calculations and experimental flow cytometry scatter plots. GLMT calculations with these conversion factors accurately predict the characteristic Lissajous-like serpentine scattering plot measured by flow cytometry for microbubbles. We conclude that GLMT calculations can be combined with optical forward and side scatter measurements to accurately determine microbubble size.
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, Colorado, USA.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Satinover
authors.forename: Jacob D
authors.initials: JD
authors.lastname: Dove
authors.forename: Mark A
authors.initials: MA
authors.lastname: Borden
mesh_terms: D003198:Computer Simulation; D003287:Contrast Media / Q000737:chemistry* / Q000528:radiation effects*; D005434:Flow Cytometry / Q000379:methods*; D019220:High-Energy Shock Waves; D045423:Microbubbles; D008956:Models, Chemical; D057054:Molecular Imaging / Q000379:methods*; D010316:Particle Size; D012031:Refractometry / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Electro-impedance sensing; Flow cytometry; Generalized Lorenz-Mie theory; Laser obscuration/extinction; Lipid-coated microbubbles; Polystyrene beads