A Pilot Study to Assess the Performance of Phase-Sensitive Breast Tomosynthesis.

Background A new modality, phase-sensitive breast tomosynthesis (PBT), may have similar diagnostic performance to conventional breast tomosynthesis but with a reduced radiation dose. Purpose To perform a pilot study of the performance of a novel PBT system compared with conventional digital breast tomosynthesis (DBT) in patients undergoing additional diagnostic imaging workup for breast lesions. Materials and Methods In a prospective study from June 2020 to March 2021, participants with suspicious breast lesions detected at screening DBT or MRI were recruited for additional PBT imaging before additional diagnostic workup or biopsy.

A phase sensitive x-ray breast tomosynthesis system: Preliminary patient images with cancer lesions.

Phase-sensitive x-ray imaging continues to attract research for its ability to visualize weakly absorbing details like those often encountered in biology and medicine. We have developed and assembled the first inline-based high-energy phase sensitive breast tomosynthesis (PBT) system, which is currently undergoing patient imaging testing at a clinical site. The PBT system consists of a microfocus polychromatic x-ray source and a direct conversion-based flat panel detector coated with a 1 mm thick amorphous selenium layer allowing a high detective quantum efficiency at high energies.

Mathematical estimation of half-value layer thicknesses.

Objective: The objective of this article is to introduce a simplified and swift method to satisfactorily estimate the half-value layers (HVL), quarter-value layer (QVL), and tenth-value layer (TVL) from the x-ray spectra emitted by any diagnostic radiology or kV radiotherapy x-ray tubes.

Methods: A CdTe x-ray and Gamma detector (X-123 CdTe, AmpTek Inc.) is used to measure the x-ray spectra at four different x-ray energies (low, mid, high energy x-rays) with different external filtering.

Development and preclinical evaluation of a patient-specific high energy x-ray phase sensitive breast tomosynthesis system.

Background: This article reports the first x-ray phase sensitive breast tomosynthesis (PBT) system that is aimed for direct translation to clinical practice for the diagnosis of breast cancer.

Purpose: To report the preclinical evaluation and comparison of the newly built PBT system with a conventional digital breast tomosynthesis (DBT) system.

Methods And Materials: The PBT system is developed based on a comprehensive inline phase contrast theoretical model.

The role of chest computed tomography in the management of COVID-19: A review of results and recommendations.

The impact of the COVID-19 pandemic has been worldwide, and clinicians and researchers around the world have been working to develop effective and efficient methods for early detection as well as monitoring of the disease progression. This minireview compiles the various agency and expert recommendations, along with results from studies published in numerous countries, in an effort to facilitate the research in imaging technology development to benefit the detection and monitoring of COVID-19. To the best of our knowledge, this is the first review paper on the topic, and it provides a brief, yet comprehensive analysis.

Simultaneous quantification of candesartan and irbesartan in rabbit eye tissues by liquid chromatography-tandem mass spectrometry.

Diabetic retinopathy is a major cause of vision loss in adults. Novel eye-drop formulations of candesartan and irbesartan are being developed for its cure or treatment. To support a preclinical trial in rabbits, it was critical to develop and validate a new LC-MS/MS method for simultaneous quantification of candesartan and irbesartan in rabbit eye tissues (cornea, aqueous humor, vitreous body and retina/choroid).

Aberrant DNA Methylation in Acute Myeloid Leukemia and Its Clinical Implications.

Acute myeloid leukemia (AML) is a heterogeneous disease that is characterized by distinct cytogenetic or genetic abnormalities. Recent discoveries in cancer epigenetics demonstrated a critical role of epigenetic dysregulation in AML pathogenesis. Unlike genetic alterations, the reversible nature of epigenetic modifications is therapeutically attractive in cancer therapy.

A defective flexible loop contributes to the processing and gating defects of the predominant cystic fibrosis-causing mutation.

People with the genetic disease cystic fibrosis (CF) often carry a deletion mutation ΔF508 on the gene encoding the CF transmembrane conductance regulator (CFTR) Cl channel. This mutation greatly reduces the CFTR maturation process and slows the channel opening rate. Here, we investigate whether residues near F508 contribute to these defects in ΔF508-CFTR.

Detectability comparison of simulated tumors in digital breast tomosynthesis using high-energy X-ray inline phase sensitive and commercial imaging systems.

This study compared the detectability of simulated tumors using a high-energy X-ray inline phase sensitive digital breast tomosynthesis (DBT) prototype and a commercial attenuation-based DBT system. Each system imaged a 5-cm thick modular breast phantom with 50-50 adipose-glandular percentage density containing contrast-detail (CD) test objects to simulate different tumor sizes. A commercial DBT system acquired 15 projection views over 15 degrees (15d-15p) was used to acquire the attenuation-based projection views and to reconstruct the conventional DBT slices.

Quantitative investigation of the edge enhancement in in-line phase contrast projections and tomosynthesis provided by distributing microbubbles on the interface between two tissues: a phantom study.

The objective of this study was to quantitatively investigate the ability to distribute microbubbles along the interface between two tissues, in an effort to improve the edge and/or boundary features in phase contrast imaging. The experiments were conducted by employing a custom designed tissue simulating phantom, which also simulated a clinical condition where the ligand-targeted microbubbles are self-aggregated on the endothelium of blood vessels surrounding malignant cells. Four different concentrations of microbubble suspensions were injected into the phantom: 0%, 0.

Characterization of Continuous and Pulsed Emission modes of a Hybrid Micro Focus X-ray Source for Medical Imaging Applications.

The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16-50 μm as the source output power changes from 10-39 W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution.

Using Microbubble as Contrast Agent for High-Energy X-Ray In-line Phase Contrast Imaging: Demonstration and Comparison Study.

The ability of microbubbles to benefit the imaging quality of high-energy in-line phase contrast as compared with conventional low-energy contact mode radiography was investigated. The study was conducted by comparing in-line phase contrast imaging with conventional contact-mode projection imaging under the same dose delivered to a phantom. A custom-designed phantom was employed to simulate a segment of human blood vessel injected with microbubble suspensions.

Detectability comparison between a high energy x-ray phase sensitive and mammography systems in imaging phantoms with varying glandular-adipose ratios.

The objective of this study was to demonstrate the potential benefits of using high energy x-rays in comparison with the conventional mammography imaging systems for phase sensitive imaging of breast tissues with varying glandular-adipose ratios. This study employed two modular phantoms simulating the glandular (G) and adipose (A) breast tissue composition in 50 G-50 A and 70 G-30 A percentage densities. Each phantom had a thickness of 5 cm with a contrast detail test pattern embedded in the middle.

Noise Power Characteristics of a Micro-Computed Tomography System.

Objective: The aim of this study was to investigate the noise power properties of a micro-computed tomography (micro-CT) system under different operating conditions.

Methods: A commercial micro-CT was used in the study that used a flat panel detector with a 127-μm-pixel pitch and a micro-focus x-ray tube. Conical tubes of various diameters were used under different acquisition conditions.

Use of basic mobile phase to improve chromatography and boost sensitivity for quantifying tetrahydrocurcumin in human plasma by LC-MS/MS.

Tetrahydrocurcumin (THC), a major metabolite of curcumin, is often quantified by LC-MS or LC-MS/MS using acidic mobile phases due to the concern of its instability in a basic medium. However, acidic mobile phases often lead to poor chromatography (e.g.

Low dose high energy x-ray in-line phase sensitive imaging prototype: Investigation of optimal geometric conditions and design parameters.

The objective of this study was to investigate the optimization of a high energy in-line phase sensitive x-ray imaging prototype under different geometric and operating conditions for mammography application. A phase retrieval algorithm based on phase attenuation duality (PAD) was applied to the phase contrast images acquired by the prototype. Imaging performance was investigated at four magnification values of 1.

Characterization of a high-energy in-line phase contrast tomosynthesis prototype.

Purpose: In this research, a high-energy in-line phase contrast tomosynthesis prototype was developed and characterized through quantitative investigations and phantom studies.

Methods: The prototype system consists of an x-ray source, a motorized rotation stage, and a CMOS detector with a pixel pitch of 0.05 mm.

Image quality and dose efficiency of high energy phase sensitive x-ray imaging: phantom studies.

The goal of this preliminary study was to perform an image quality comparison of high energy phase sensitive imaging with low energy conventional imaging at similar radiation doses. The comparison was performed with the following phantoms: American College of Radiology (ACR), contrast-detail (CD), acrylic edge and tissue-equivalent. Visual comparison of the phantom images indicated comparable or improved image quality for all phantoms.

Dose and detectability improvements with high energy phase sensitive x-ray imaging in comparison to low energy conventional imaging.

The objective of this study was to demonstrate the potential benefits of using high energy x-rays for phase sensitive breast imaging through a comparison with conventional mammography imaging. We compared images of a contrast-detail phantom acquired on a prototype phase sensitive x-ray imaging system with images acquired on a commercial flat panel digital mammography unit. The phase contrast images were acquired using a micro-focus x-ray source with a 50 µm focal spot at 120 kVp and 4.

A method of measuring gold nanoparticle concentrations by X-ray fluorescence for biomedical applications.

Purpose: This paper reports a technique that enables the quantitative determination of the concentration of gold nanoparticles (GNPs) through the accurate detection of their fluorescence radiation in the diagnostic x-ray spectrum.

Methods: Experimentally, x-ray fluorescence spectra of 1.9 and 15 nm GNP solutions are measured using an x-ray spectrometer, individually and within chicken breast tissue samples.

The effects of x-ray beam hardening on detective quantum efficiency and radiation dose.

The goal of this preliminary study was to investigate the effects of x-ray beam hardening on the detective quantum efficiency (DQE) and the radiation dose of an inline x-ray imaging system. The ability to decrease the risk of harmful radiation to the patient without compromising the detection capability would more effectively balance the tradeoff between image quality and radiation dose, and therefore benefit the fields of diagnostic x-ray imaging, especially mammography. The DQE and the average glandular dose were both calculated under the same experimental conditions for a range of beam hardening levels, corresponding to no added beam hardening and two thicknesses each of Rhodium (Rh) and Molybdenum (Mo) filters.

Dicer-dependent microRNA pathway controls invariant NKT cell development.

Invariant NK T (iNKT) cells are a separate lineage of T lymphocytes with innate effector functions. They express an invariant TCR specific for lipids presented by CD1d and their development and effector differentiation rely on a unique gene expression program. We asked whether this program includes microRNAs, small noncoding RNAs that regulate gene expression posttranscriptionally and play a key role in the control of cellular differentiation programs.

Episodic-like memory deficits in the APPswe/PS1dE9 mouse model of Alzheimer's disease: relationships to beta-amyloid deposition and neurotransmitter abnormalities.

Transgenic mice made by crossing animals expressing mutant amyloid precursor protein (APPswe) to mutant presenilin 1 (PS1dE9) allow for incremental increases in Abeta42 production and provide a model of Alzheimer-type amyloidosis. Here, we examine cognition in 6- and 18-month old transgenic mice expressing APPswe and PS1dE9, alone and in combination. Spatial reference memory was assessed in a standard Morris Water Maze task followed by assessment of episodic-like memory in Repeated Reversal and Radial Water maze tasks.