Reconstruction of thermoacoustic emission sources induced by proton irradiation using numerical time reversal.

Mapping of dose delivery in proton beam therapy can potentially be performed by analyzing thermoacoustic emissions measured by ultrasound arrays. Here, a method is derived and demonstrated for spatial mapping of thermoacoustic sources using numerical time reversal, simulating re-transmission of measured emissions into the medium.Spatial distributions of thermoacoustic emission sources are shown to be approximated by the analytic-signal form of the time-reversed acoustic field, evaluated at the time of the initial proton pulse.

Thermoacoustic range verification during pencil beam delivery of a clinical plan to an abdominal imaging phantom.

Purpose: The purpose of this phantom study is to demonstrate that thermoacoustic range verification could be performed clinically. Thermoacoustic emissions generated in an anatomical multimodality imaging phantom during delivery of a clinical plan are compared to simulated emissions to estimate range shifts compared to the treatment plan.

Methods: A single-field 12-layerproton pencil beam scanning (PBS)treatment plancreated in Pinnacle prescribing6 Gy/fractionwas delivered by a superconducting synchrocyclotron to a triple modality (CT, MRI, and US) abdominal imaging phantom.

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited.

Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19.

Design, Setting, And Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin.

Thermoacoustic range verification in the presence of acoustic heterogeneity and soundspeed errors - Robustness relative to ultrasound image of underlying anatomy.

Purpose: To demonstrate robustness of thermooacoustic range verification to acoustic heterogeneity and discrepancies between assumed and true propagation speed, i.e., soundspeed errors.

Two-stage ionoacoustic range verification leveraging Monte Carlo and acoustic simulations to stably account for tissue inhomogeneity and accelerator-specific time structure - A simulation study.

Purpose: Range errors constrain treatment planning by limiting choice of ion beam angles and requiring large margins. Ionoacoustic range verification requires recovering the location of an acoustic source from low frequency signals. A priori information is applied to stably overcome resolution limits of inverse acoustic source imaging in this simulation study.

Thermoacoustic range verification using a clinical ultrasound array provides perfectly co-registered overlay of the Bragg peak onto an ultrasound image.

The potential of particle therapy due to focused dose deposition in the Bragg peak has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying the location of the Bragg peak onto a standard ultrasound image. Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the cyclotron inflector.

Toward Quantitative Whole Organ Thermoacoustics With a Clinical Array Plus One Very Low-Frequency Channel Applied to Prostate Cancer Imaging.

Thermoacoustics has the potential to provide quantitative images of intrinsic tissue properties, most notably electrical conductivity in Siemens/meter, much as shear wave elastography provides tissue stiffness in kilopascal. Although thermoacoustic imaging with optical excitation has been commercialized for small animals, it has not yet made the transition to clinic for whole organ imaging in humans. The purpose of this work was to develop and validate specifications for a clinical ultrasound array for quantitative whole organ thermoacoustic imaging.

Thermoacoustic contrast of prostate cancer due to heating by very high frequency irradiation.

Applying the thermoacoustic (TA) effect to diagnostic imaging was first proposed in the 1980s. The object under test is irradiated by high-power pulses of electromagnetic energy, which heat tissue and cause thermal expansion. Outgoing TA pressure pulses are detected by ultrasound transducers and reconstructed to provide images of the object.

Volumetric thermoacoustic imaging over large fields of view.

The thermoacoustic (TA) contrast mechanism relies on rapid tissue heating and subsequent thermal expansion. TA computerized tomography (TCT) is therefore inverse source imaging. The TA contrast mechanism provides information complementary to that revealed by current diagnostic imaging techniques, but has been limited to just a few centimeters depth penetration.

The effect of sample holder geometry on electromagnetic heating of nanoparticle and NaCl solutions at 13.56 MHz.

Electromagnetic absorption and subsequent heating of nanoparticle solutions and simple NaCl ionic solutions is examined for biomedical applications in the radiofrequency range at 13.56 MHz. It is shown via both theory and experiment that for in vitro measurements the shape of the solution container plays a major role in absorption and heating.

Reducing utilization by uninsured frequent users of the emergency department: combining case management and drop-in group medical appointments.

Background: Patients with complex behavioral health and medical problems can have a disproportionate impact on emergency departments.

Methods: We identified a cohort of 255 low-income, uninsured patients who had used inpatient or emergency department services more than 6 times in the previous 12 months. Between July 2010 and June 2011 we enrolled 36 of these high-risk patients to participate in a twice-weekly drop-in group medical appointment staffed by an interdisciplinary team of a family physician, behavioral health professional, and nurse case manager.

Specific heat capacity of freshly excised prostate specimens.

The specific heat capacity of tissue is a critical parameter for thermal therapies that act over a long period of time. It is also critical for thermoacoustic signal generation. We present ex vivo measurements of specific heat capacity performed by a dual-pin probe with tight temperature control of the specimen.

Systemic reactions with aeroallergen cluster immunotherapy in a clinical practice.

Background: Subcutaneous allergen-specific immunotherapy is a proven, highly effective treatment for immunoglobulin E-mediated diseases. Despite its proven benefits, only a small percentage of patients with allergic disease use immunotherapy, in part because of the inconvenience associated with treatment. Cluster allergen immunotherapy may offer patients a more convenient treatment option but is prescribed infrequently because of the perception that accelerated immunotherapy buildup leads a higher rate of systemic reactions.

Improving asthma care in emergency departments: results of a multihospital collaborative quality initiative in rural western North Carolina.

Background: In North Carolina, nearly one-fourth of persons with asthma visit an emergency department (ED) or urgent care center at least once a year because of an exacerbation of asthma symptoms. The Emergency Department Asthma Program was a quality-improvement initiative designed to better understand the population of patients who use the ED for asthma care in rural western North Carolina and to demonstrate whether EDs at small hospitals could, by implementing National Asthma Education and Prevention Program treatment guidelines, improve asthma care and reduce subsequent asthma-related ED visits.

Methods: Eight hospitals in western North Carolina participated in the project, which lasted from November 2003 through December 2007.

Effect of chromated copper arsenate structures on adjacent soil arsenic concentrations.

Structures made of chromated copper arsenic (CCA) have been shown to leach arsenic into the surrounding soil. Soil cores were taken adjacent to six CCA decks at 0, 15, 60 and 300 cm from the deck at depths of 0-10, 10-20, and 20-30 cm, and were analyzed for soil arsenic concentrations. Median soil arsenic concentrations ranged from 1.

Ex vivo thermoacoustic imaging over large fields of view with 108 MHz irradiation.

Thermoacoustic signals are generated over a large field of view by 900 ns TE10 pulses with 108 MHz carrier frequency. Test specimens selectively absorb the TE10 pulse energy producing rapid thermal expansions that generate ultrasonic pulses. 108 MHz irradiation provides excellent depth penetration in soft tissue, allowing blood and physiologic saline to generate strong signals.

A pilot survey of in-service home arsenic tracked in from chromated copper arsenate-treated decks.

Arsenic is a known carcinogen. It is also known to be readily dislodgeable from chromated copper arsenate (CCA)-treated lumber. The floors of in-service homes were tested for inorganic arsenic using a wipe method similar to the U.

A pilot simulation study of arsenic tracked from CCA-treated decks onto carpets.

A controlled simulation experiment was performed to assess whether dislodgeable arsenic can be tracked onto carpets via foot traffic from chromated copper arsenate (CCA) pressure-treated decks. The pilot simulation study demonstrated that it is possible to track arsenic from CCA-decks onto carpets under the test conditions evaluated. A total of nine CCA-decks and two non-CCA-treated control surfaces were tested under wet and dry conditions.

Measurement of broadband temperature-dependent ultrasonic attenuation and dispersion using photoacoustics.

The broadband ultrasonic characterization of biological fluids and tissues is important for the continued development and application of high-resolution ultrasound imaging modalities. Here, a photoacoustic technique for the transmission measurement of temperature-dependent ultrasonic attenuation and dispersion is described. The system uses a photoacoustic plane wave source constructed from a polymethylmethacrylate substrate with a thin optically absorbent layer.

Effect of a computerized body mass index prompt on diagnosis and treatment of adult obesity.

Background: In obese adults, physicians often fail to identify obesity and recommend treatments for it. We sought to determine whether a computerized body mass index (BMI) chart prompt would increase the likelihood that patients of family physicians would be diagnosed with obesity and referred for obesity treatment.

Methods: A total of 846 obese patients of 37 family physicians were randomly assigned to either have a patient's BMI chart prompt placed in their electronic medical record (intervention group) or not have a BMI prompt (comparison group) placed in the record.

RF testbed for thermoacoustic tomography.

Thermoacoustic signal excitation is a function of intrinsic tissue properties and illuminating electric field. De-ionized (DI) water is a preferred acoustic coupling medium for thermoacoustics because acoustic and electromagnetic waves propagate in DI water with very little loss. We have designed a water-filled testbed propagating a controlled electric field with respect to pulse shape, power, and polarization.

Collateral benefits and hidden hazards of soil arsenic during abatement assessment of residential lead hazards.

Abatement of soil-lead hazards may also reduce human exposure to other soil toxins, thereby achieving significant collateral benefits that are not accounted for today. This proposition was tested with the specific case of soil-arsenic, where 1726 residential soil samples were collected and analyzed for lead and arsenic. The study found that these two toxins coexisted in most samples, but their concentrations were weakly correlated, reflecting the differing sources for each toxin.

Effects of fluoridation and disinfection agent combinations on lead leaching from leaded-brass parts.

This study concerns effects on water-borne lead from combinations of chlorine (CL) or chloramines (CA) with fluosilicic acid (FSA) or sodium fluoride (NaF). CL is known to corrode brass, releasing lead from plumbing devices. It is known that CA and CL in different ratios with ammonia (NH) mobilize copper from brass, which we have found also enhances elution of lead from leaded brass alloys.

Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals.

Silicofluorides (SiFs), fluosilicic acid (FSA) and sodium fluosilicate (NaFSA), are used to fluoridate over 90% of US fluoridated municipal water supplies. Living in communities with silicofluoride treated water (SiFW) is associated with two neurotoxic effects: (1) Prevalence of children with elevated blood lead (PbB>10microg/dL) is about double that in non-fluoridated communities (Risk Ratio 2, chi2p<0.01).

Reducing lead exposure from drinking water: recent history and current status.

This article discusses the issue of lead contamination of drinking water, noting the various regulatory-driven measures that have been adopted in the U.S. since 1986 to address this public health issue.