Acoustics 2 Contrast Media 2 Microbubbles 2 Phospholipids 2 Sulfur Hexafluoride Ultrasound contrast agent 2 acoustics 2 contrast agent BR1 2 contrast medium 2 microbubble 2 phospholipid 2 radiation response 2 sulfur hexafluoride 2 Acoustic nonlinearity parameters 1 Acoustic properties 1 Article 1 Collateral damage 1 Contrast ultrasound 1 Definity 1 Dose monitoring 1 Dosimetry 1 Fluorocarbons 1 Liquids 1 Low frequency limits 1 Mathematical derivation 1 Megavoltage 1 Megavoltage photons 1 Micro-bubble 1 Models, Theoretical 1 Negative nonlinearities 1