Optoacoustic imaging using thin polymer étalon

Optical detection of ultrasound is a promising technique for high frequency imaging arrays. Detection resolution approaches the optical resolution, which can be on the order of the optical wavelength. We describe here an optical technique for ultrasound detection based on a thin (10 μm)(10μm) Fabry–Perot étalon optimized for high resolution imaging. The signal to noise ratio (SNR) approaches that of an ideal piezoelectric transducer over a 100 MHz100MHz bandwidth. Array functionality is demonstrated by scanning a probe beam along a line. Thermoelastic excitation was applied to generate acoustic waves in a test phantom containing a single “pointlike” source. An image of the source was reconstructed using signals acquired from the étalon detector array.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87845/2/134102_1.pd

Nanoparticles for photoacoustic imaging

Nanoparticles have been designed and applied as contrast enhancers in various optical imaging techniques, such as optical coherence tomography, fluorescence imaging, and optical reflectance microscopy. As an emerging hybrid imaging modality, photoacoustic imaging (PAI) has also benefited from the application of these nanoparticle-based contrast agents. We review this rapidly growing field and describe the applications of nanoparticles in PAI. Particular focus is given to nanoparticles whose absorption mechanism is based on surface plasmon resonance, including gold nanoshells, nanorods, and nanocages. Dye-embedded nanoparticles are also reviewed. Specifically, the design and application of each nanoparticle-based contrast agent in relation to the field of PAI are detailed. Copyright © 2009 John Wiley & Sons, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63039/1/42_ftp.pd

Ultrasound detection using polymer microring optical resonator

Application of polymer waveguide microring resonators for high-frequency ultrasound detection is presented. The device consists of a microring optical resonator coupled to a straight optical waveguide which serves as input and output ports. Acoustic waves irradiating the ring waveguide induce strain modifying the waveguide cross section. As a consequence, the effective refractive index of optical waves propagating along the ring is modified. The sharp wavelength dependence of the high QQ-factor resonator enhances the optical response to acoustic strain. High sensitivity is demonstrated experimentally in detecting broadband ultrasound pulses from a 10 MHz10 MHz transducer. Methods of extending the technique to form multi-element ultrasonic arrays for imaging applications are proposed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70498/2/APPLAB-85-22-5418-1.pd

Optical generation of high frequency ultrasound using two-dimensional gold nanostructure

A two-dimensional (2D) gold nanostructure is used to optically generate high frequency ultrasound. The structure consists of 2D arrangements of gold nanoparticles, sandwiched between a transparent substrate and a 4.5 μm4.5μm thick polydimethylsiloxane (PDMS) layer. The acoustic signal displays significant improvements compared to a bulk black PDMS films (the current state of the art) at frequencies from 50 to 100 MHz50to100MHz. The high optical extinction ratio of the gold nanostructure provides a convenient method to construct an integrated transmit/receive optoacoustic array. These results show that a 2D gold nanostructure can be used to produce high frequency arrays for ultrasound imaging.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87823/2/093901_1.pd

Mycobacterium haemophilum and Lymphadenitis in Immunocompetent Children, Israel

The database of a major microbiology laboratory in Israel was searched to determine the prevalence of nontuberculous mycobacterial lymphadenitis in immunocompetent children. We observed a 4-fold increase in nontuberculous mycobacteria isolates during 1985–2006, which was attributable mainly to increased detection of Mycobacterium haemophilum starting in 1996

Polymer microring resonators for high-frequency ultrasound detection and imaging

Abstract-Polymer microring resonators fabricated by nanoimprinting are presented as a means of ultrasound detection. Acoustic waves impinging on a ring-shaped optical resonator cause strain in the ring dimensions, modulating optical output. Basic acoustic and optical characteristics of the microring sensor are presented. Measurements at several frequencies show a high sensitivity and low noise-equivalent pressure. The angular response is determined by sensing the optoacoustic excitation of a 49 µm polyester microsphere and shows wide-angle sensitivity. A 1-D array consisting of four microrings is demonstrated using wavelength multiplexing for addressing each element. The high sensitivity, bandwidth, and angular response make it a potentially useful sensor platform for many applications including high-frequency ultrasonic and photoacoustic imaging

Pediatric antibiotic stewardship programs in Europe: a pilot survey among delegates of The European Academy of Pediatrics

BackgroundAntimicrobial resistance (AMR) is one of the leading causes of morbidity and mortality worldwide. Efforts to promote the judicious use of antibiotics and contain AMR are a priority of several medical organizations, including the WHO. One effective way to achieve this goal is the deployment of antibiotic stewardship programs (ASPs). This study aimed to survey the current situation of pediatric ASPs in European countries and establish a baseline for future attempts to harmonize pediatric ASPs and antibiotic use in Europe.MethodsA web-based survey was conducted among national delegates of the European Academy of Paediatrics (EAP). The survey assessed the presence of pediatric ASPs in the representatives’ countries in the inpatient and outpatient settings, the staff included in the programs, and their detailed activities regarding antibiotic use.ResultsOf the 41 EAP delegates surveyed, 27 (66%) responded. Inpatient pediatric ASPs were reported in 74% (20/27) countries, and outpatient programs in 48% (13/27), with considerable variability in their composition and activities. Guidelines for managing pediatric infectious diseases were available in nearly all countries (96%), with those for neonatal infections (96%), pneumonia (93%), urinary tract (89%), peri-operative (82%), and soft tissue (70%) infections being the most common. Pediatric ASPs were reported at the national (63%), institutional (41%), and regional/local (<15%) levels. Pediatricians with infectious disease training (62%) and microbiologists (58%) were the most common members of the program personnel, followed by physician leaders (46%), infectious disease/infection control physicians (39%), pharmacists (31%), and medical director representatives (15%). Activities of the pediatric ASPs included educational programs (85%), monitoring and reporting of antibiotic use (70%) and resistance (67%), periodic audits with feedback (44%), prior approval (44%), and post-prescription review of selected antibiotic agents (33%).ConclusionAlthough pediatric ASPs exist in most European countries, their composition and activities vary considerably across countries. Initiatives to harmonize comprehensive pediatric ASPs across Europe are needed