High-energy X-ray phase-contrast CT of an adult human chest phantom.

Propagation-based phase-contrast X-ray imaging is a promising technique for in vivo medical imaging, offering lower radiation doses than traditional attenuation-based imaging. Previous studies have focused on X-ray energies below 50keV for small-animal imaging and mammography. Here, we investigate the feasibility of high-energy propagation-based computed tomography for human adult-scale lung imaging at the Australian Synchrotron's Imaging and Medical Beamline.

3DMPR - a robust morphological approach for applying phase retrieval in proximity to highly attenuating objects in computed tomography.

X-ray imaging is a fast, precise and non-invasive method of imaging which, when combined with computed tomography, provides detailed 3D rendering of samples. Incorporating propagation-based phase contrast can vastly improve data quality for weakly attenuating samples via phase retrieval, allowing radiation exposure to be reduced. However, applying phase retrieval to multi-material samples commonly requires the choice of which material boundary to tune the reconstruction.

Low-dose, high-resolution CT of infant-sized lungs via propagation-based phase contrast.

Many lung diseases require high-resolution imaging for accurate diagnosis and treatment. Computed tomography (CT) is the gold-standard technique for non-invasive lung disease detection, but it presents a risk to the patient through the relatively high ionising radiation dose required. Utilising the X-ray phase information has demonstrated improvements in image quality over absorption contrast in small animal models, at equal or lower radiation levels.

Single-exposure x-ray dark-field imaging via a dual-energy propagation-based setup.

X-ray dark-field imaging visualizes scattering from sample microstructure and has found application in medical and security contexts. While most x-ray dark-field imaging techniques rely on masks, gratings, or crystals, recent work on the Fokker-Planck model of diffusive imaging has enabled dark-field imaging in the propagation-based geometry. Images captured at multiple propagation distances or x-ray energies can be used to reconstruct dark-field from propagation-based images but have previously required multiple exposures.

Using X-ray velocimetry to measure lung function and assess the efficacy of a pseudomonas aeruginosa bacteriophage therapy for cystic fibrosis.

Phase contrast x-ray imaging (PCXI) provides high-contrast images of weakly-attenuating structures like the lungs. PCXI, when paired with 4D X-ray Velocimetry (XV), can measure regional lung function and non-invasively assess the efficacy of emerging therapeutics. Bacteriophage therapy is an emerging antimicrobial treatment option for lung diseases such as cystic fibrosis (CF), particularly with increasing rates of multi-drug-resistant infections.

Printable Perovskite Diodes for Broad-Spectrum Multienergy X-Ray Detection.

Multienergy X-ray detection is critical to effectively differentiate materials in a variety of diagnostic radiology and nondestructive testing applications. Silicon and selenium X-ray detectors are the most common for multienergy detection; however, these present poor energy discrimination across the broad X-ray spectrum and exhibit limited spatial resolution due to the high thicknesses required for radiation attenuation. Here, an X-ray detector based on solution-processed thin-film metal halide perovskite that overcomes these challenges is introduced.

Precise phase retrieval for propagation-based images using discrete mathematics.

The ill-posed problem of phase retrieval in optics, using one or more intensity measurements, has a multitude of applications using electromagnetic or matter waves. Many phase retrieval algorithms are computed on pixel arrays using discrete Fourier transforms due to their high computational efficiency. However, the mathematics underpinning these algorithms is typically formulated using continuous mathematics, which can result in a loss of spatial resolution in the reconstructed images.

Quantifying lung aeration in neonatal lambs at birth using lung ultrasound.

Background: Lung ultrasound (LUS) is a safe and non-invasive tool that can potentially assess regional lung aeration in newborn infants and reduce the need for X-ray imaging. LUS produces images with characteristic artifacts caused by the presence of air in the lung, but it is unknown if LUS can accurately detect changes in lung air volumes after birth. This study compared LUS images with lung volume measurements from high-resolution computed tomography (CT) scans to determine if LUS can accurately provide relative measures of lung aeration.

When the emotions really started kicking in, which ended up being a problem: sex, HIV, and emotions among young gay and bisexual men.

Interviews from 10 young gay and bisexual men aged 18 to 29 were examined to explore how young gay and bisexual men make decisions regarding sexual behaviors in the age of AIDS. Three main themes emerged: (a) disconnections between what an individual knows about HIV, their motivations to remain HIV-negative, and their sexual behaviors; (b) a struggle to connect emotionally and intimately with another man; and (c) a power dynamic whereby the individual acts as an autonomous decider in the decision-making process. Participants indicated high levels of HIV knowledge, and were engaged in a struggle to balance emotional experiences with sexual partners in a complex gendered dynamic.

Alcohol use among young men who have sex with men.

This study reveals associations between alcohol use and demographic variables, as well as the relation between alcohol use and sexual activity, using episodic data. Data were obtained during summer and fall 2008 from a sample of 558 gay, bisexual, and other young men who have sex with men (YMSM), ages of 13-29 years in New York City. Recruitment strategies targeted potential participants at gay-related venues and public spaces often frequented by YMSM.

Substance use in the MSM population of New York City during the era of HIV/AIDS.

This literature review considers the historical significance, emergence of, and interplay between the HIV and illicit drug use epidemics among gay, bisexual, and other men who have sex with men (MSM) in New York City (NYC). The continual rise in HIV infections in recent years among MSM, particularly among young MSM (YMSM), commands a need for the examination of the effectiveness of current HIV prevention strategies and a more comprehensive understanding of the complex biopsychosocial influences that place YMSM at risk. A chronological perspective of both the HIV and illicit drug use epidemics affecting NYC MSM is presented, followed by a review of the existing research on the synergistic relation between the two.

Environmental factors in relation to unprotected sexual behavior among gay, bisexual, and other MSM.

This descriptive article illustrates the casual sexual behaviors of a diverse sample (N = 311) of gay, bisexual, and other men who have sex with men (MSM) regularly attending gyms in New York City. Approximately 88% of the sample noted sex with a casual partner in the previous 6 months. Participants reported the frequency of unprotected sexual acts, the perceived HIV status of their partners, and the contexts where they met their casual sex partners.

Sexual practices of gay, bisexual, and other nonidentified MSM attending New York City gyms: patterns of serosorting, strategic positioning, and context selection.

This descriptive paper characterizes the sexual behaviors of a diverse sample (N=311) of gay, bisexual, and other nonidentified men who have sex with men (MSM) who regularly attended gyms in New York City. Approximately 50% of the sample indicated sex with primary male partners, while 88% of the men had sexual relations with male casual partners in the 6 months prior to assessment. The participants met their casual partners in a variety of different venues, including the Internet.