title: Heat-sensitive microbubbles for intraoperative assessment of cancer ablation margins.
abstract: A heat-sensitive microbubble (HSM) agent, comprising a core of liquid perfluorocarbon (PFC) compound and a shell of biodegradable poly lactic-co-glycolic acid (PLGA), was fabricated using an emulsion evaporation method. Optical microscopic imaging showed that heating the HSM suspension to 55 degrees C activated the HSMs for significant volumetric expansion. After placing a HSM-dispersed agar-agar gel phantom in a 55 degrees C water bath for 10 min, the phantom became ultrasonically hyperechoic due to the HSM expansion. In an ex vivo test, a porcine tissue sample was injected with the HSM suspension and placed in a 55 degrees C water bath for 10 min. US imaging clearly identified the hyperechoic regions resulted from the HSM activation. The hyperechoic regions in the tissue sample kept a strong US contrast for more than 1 h. In a simulated ablation process, a HSM-dispersed agar-agar gel phantom was ablated by a cylindrical heating element. US imaging accurately estimated the ablation margin propagation while thermographic imaging underestimated the ablation margin. Our experiments demonstrated that the HSM agent could be used as a novel contrast agent for intraoperative assessment of ablation margins in cancer thermal ablation therapies.
authors: Department of Biomedical Engineering, The Ohio State University, 270 Bevis Hall, 1080 Carmack Road, Columbus, OH 43210, USA.
authors: Jiwei
authors: J
authors: Huang
authors: Jeff S
authors: JS
authors: Xu
authors: Ronald X
authors: RX
authors: Xu
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry* / Q000528:radiation effects; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D045423:Microbubbles; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D019047:Phantoms, Imaging; D013552:Swine; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media