title: Development and initial application of a fully integrated photoacoustic micro-ultrasound system.
abstract: Photoacoustic (PA) imaging for biomedical applications has been under development for many years. Based on the many advances over the past decade, a new photoacoustic imaging system has been integrated into a micro-ultrasound platform for co-registered PA-ultrasound (US) imaging. The design and implementation of the new scanner is described and its performance quantified. Beamforming techniques and signal processing are described, in conjunction with in vivo PA images of normal subcutaneous mouse tissue and selected tumor models. In particular, the use of the system to estimate the spatial distribution of oxygen saturation (sO2) in blood and co-registered with B-mode images of the surrounding anatomy are investigated. The system was validated in vivo against a complementary technique for measuring partial pressure of oxygen in blood (pO2). The pO2 estimates were converted to sO2 values based on a standard dissociation curve found in the literature. Preliminary studies of oxygenation effects were performed in a mouse model of breast cancer (MDA-MB-231) in which control mice were compared with mice treated with a targeted antiangiogenic agent over a 3 d period. Treated mice exhibited a >90% decrease in blood volume, an 85% reduction in blood wash-in rate, and a 60% decrease in relative tissue oxygenation.
authors: VisualSonics Inc., Toronto, ON, Canada.
authors: Andrew
authors: A
authors: Needles
authors: Andrew
authors: A
authors: Heinmiller
authors: John
authors: J
authors: Sun
authors: Catherine
authors: C
authors: Theodoropoulos
authors: David
authors: D
authors: Bates
authors: Desmond
authors: D
authors: Hirson
authors: Melissa
authors: M
authors: Yin
authors: F Stuart
authors: FS
authors: Foster
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D005260:Female; D005336:Fiber Optic Technology; D008321:Mammary Glands, Animal / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D051379:Mice; D055616:Microtechnology / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000032:analysis; D061088:Photoacoustic Techniques / Q000295:instrumentation / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
chemical_list: D000970:Antineoplastic Agents; D010108:Oxyhemoglobins; D010100:Oxygen