Background: Systemic lupus erythematosus (SLE) is an autoimmune disease affecting multiple organ systems triggered by the production of autoantibodies. Previous clinical studies in humans and murine ...models suggest that type I interferons (IFNs) are important for the initiation and potentiation of SLE activity. Methods: 65 consecutive patients with SLE were identified from the University of California, San Francisco Lupus Clinic with moderate-severe disease activity. 94 serological samples were collected. Type I IFN levels and the ability of plasma to induce expression of several surface markers of dendritic cell maturation were measured. Results: Type I IFN levels correlated with the presence of cutaneous manifestations, and there was a trend towards correlation with renal disease. No correlation was found between type I IFN levels and neurological disease. Type I IFN levels correlated positively with the SLEDAI score and anti-dsDNA levels and inversely with C3 levels. Interestingly, type I IFN levels were highest in African American patients. SLE plasma also induced the expression of MHC class I, CD38, and CD123 on monocytes, and was blocked by the addition of a monoclonal antibody to IFNAR1. Conclusions: The pathogenic role of type I IFN is suggested by the induction of cell surface markers for dendritic cell maturation. The potential therapeutic utility of antibodies directed to either type I IFN or IFNAR1/IFNAR2 may be of interest in further studies.
Interference effects are included in the x-ray coherent scattering models used in Monte Carlo codes by modifying each material form factor through a proper interference function, which is obtained ...directly from the measured scattering pattern. This approach is effective for non-biological materials, but it is impractical for biological tissues, due the wide composition variability they can feature. Instead, a given biological sample can be considered as a proper mixture of four basis materials: fat, water, collagen and calcium hydroxyapatite. The sample form factor can then be obtained through a weighted mean of the form factors of the basis materials, which include interference effects. Here, we fully demonstrate the validity of the proposed segmentation method by applying it to 31 biological tissue samples whose form factors are available in the literature. The segmentation, namely the determination of the optimal weight of the basis components, was carried out through a multiple linear regression or, in some cases, by using a controlled trial and error sequence. The form factors of the basis materials were extracted from previous works and elaborated to include more scattering features. In particular, they were interpolated at a denser grid. Furthermore, the data measured separately in wide angle and small angle regimes, for fat and collagen, were merged. In general, a very good agreement was obtained between the original sample and the calculated mixture, being the mean relative difference of their scattering profiles and their attenuation coefficients ∼10%. The segmentation method is fully supported by our extension to the Geant4 model of x-ray coherent scattering, which was used to compare simulated scatter distributions with known experimental data. The developed Geant4 code and a series of molecular form factors, including those of the basis materials, are freely downloadable from a dedicated web repository.
•Synthetic mammography is superior to digital mammography in microcalcs contrast.•The contrast of microcalcs on synthetic images is on average 48 % higher.•Contrast enhancement is achieved regardless ...the size and breast glandularity.•Structure noise suppression increases microcalcs’ contrast on synthetic images.•A quantitative evaluation can better address the role of synthetic mammography.
The aim of this work was to compare, in a clinical study, digital mammography and synthetic mammography imaging by evaluating the contrast in microcalcifications of different sizes.
A retrospective review of microcalcifications from 46 patients was undertaken. A Hologic 3-Dimensions mammography system and a HD Combo protocol was used for simultaneous acquisition of the digital and synthetic images. Microcalcifications were classified in accordance with their size, and patient breast images were classified in accordance with their density as adipose, moderately dense and dense. The contrast of the microcalcifications was measured and the contrast ratio between synthetic and digital images was compared. An additional qualitative assessment of the images was presented to correlate the conspicuity of the microcalcifications with the suppression of the structure noise.
Microcalcifications in adipose background always exhibit a comparable or better contrast on synthetic images, regardless their size. For moderately dense background, synthetic images show a better contrast in 91.2 % of cases for small microcalcifications and in 90.9 % of cases for large microcalcifications. For a dense background, better contrast is seen in 89.5 % of cases for small microcalcifications, and in 85.7 % of cases for large microcalcifications. The contrast ratio increases with increasing breast glandularity. The suppression of structure noise also contributes to the enhancement of microcalcifications in the synthetic images.
Synthetic mammography imaging is superior to digital mammography imaging in terms of microcalcification contrast, regardless their size and breast density.
Coronary angiography is clinically used worldwide to diagnose diseases of coronary arteries. Despite its effectiveness, this technique is quite invasive and it is associated with significant risks ...due to the arterial catheterisation needed to inject the contrast agent. A valid alternative is using the K-edge subtraction (KES) method, which is based on the subtraction of two images acquired at energies bracketing the K-edge of the contrast element. The enhanced sensitivity of KES allows the intravenous injection of the contrast agent, thus reducing the risks of catheterisation. This technique can be effectively implemented by using intense and quasi-monochromatic x-ray beams. Synchrotron radiation has been proven to work well for this purpose, but its cost and size prevent a widespread clinical application. Inverse Compton sources are among the most promising innovative sources of intense and quasi-monochromatic x-rays. These sources are intrinsically more compact than those based on synchrotron radiation. In this work, the potential application of inverse Compton radiation to KES angiography is investigated. To this purpose, after a short review of the physics behind the inverse Compton process, an analytical framework is described. The proposed model is based on the application of the KES algorithm to calculate the SNR of details inside a suitable mathematical phantom. That allowed us to identify the characteristics of an inverse Compton source required for KES imaging. In particular, it was estimated that a photon fluence of 10
ph mm
is necessary to detect signals of clinical interest. Novel sources based on inverse Compton promise to achieve this requirement with an acquisition time of few hundreds of ms. This feature, together with compactness, broad two-dimensional radiation field, absence of harmonic contamination and the ability to deliver high photon fluxes also at high energies, makes this kind of sources promising for KES angiography and other diagnostic applications.
•Dual-energy and K-edge subtraction imaging.•Rotational radiotherapy of breast cancer.•Phase-contrast imaging with coherence areas of about 10 μm.
MariX is a research infrastructure conceived for ...multi-disciplinary studies, based on a cutting-edge system of combined electron accelerators at the forefront of the world-wide scenario of X-ray sources. The generation of X-rays over a large photon energy range will be enabled by two unique X-ray sources: a Free Electron Laser and an inverse Compton source, called BriXS (Bright compact X-ray Source). The X-ray beam provided by BriXS is expected to have an average energy tunable in the range 20–180 keV and intensities between 1011 and 1013 photon/s within a relative bandwidth ΔE/E=1–10%. These characteristics, together with a very small source size (~20 μm) and a good transverse coherence, will enable a wide range of applications in the bio-medical field. An additional unique feature of BriXS will be the possibility to make a quick switch of the X-ray energy between two values for dual-energy and K-edge subtraction imaging. In this paper, the expected characteristics of BriXS will be presented, with a particular focus on the features of interest to its possible medical applications.
The SPARC_LAB Thomson source Vaccarezza, C.; Alesini, D.; Anania, M.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2016, Volume:
829
Journal Article
Peer reviewed
The SPARC_LAB Thomson source is a compact X-ray source based on the Thomson backscattering process presently under its second phase of commissioning at the LNF. The electron beam energy ranges ...between 30 and 150MeV, the electrons collide head-on with the Ti:Sapphire FLAME laser pulse the energy of which ranges between 1 and 5J with pulse lengths in the 25 fs–10ps range, this provides an X-ray energy tunability in the range of 20–500keV, with the further capability to generate strongly non-linear phenomena and to drive diffusion processes due to multiple and plural scattering effects. The experimental results of the obtained X-ray radiation are presented.
Many research and application areas demand photon sources capable of producing quasi-monochromatic X-ray beams in the multi-keV energy range with reasonably high fluxes and compact footprints. ...Besides industrial, research, commercial and cultural heritage applications, various biomedical applications could benefit from the features of this type of X-ray sources. The main target of our proposal is the production of X-ray beams with energy range tunability, monochromaticity, flux and pulse duration, compatible with those required by various pre-clinical imaging modalities and material characterization techniques, through inverse Compton scattering. This kind of source involves an infrastructure much more compact than a large Synchrotron facility and can be realized on a laboratory scale enabling an easier access to a local community of users.
•Implementation of molecular interference in the X-ray coherent scattering.•Extension to Geant4 Monte Carlo code to include updated molecular form factors.•Capability to simulate SAXS experiments for ...medical applications.
An extension to Geant4 Monte Carlo code was developed to take into account inter-atomic (molecular) interference effects in X-ray coherent scattering. Based on our previous works, the developed code introduces a set of form factors including interference effects for a selected variety of amorphous materials useful for medical applications, namely various tissues and plastics used to build phantoms. The code is easily upgradable in order to include new materials and offers the possibility to model a generic tissue as a combination of a set of four basic components. A dedicated Geant4 application for the simulation of X-ray diffraction experiments was created to validate the proposed upgrade of Rayleigh scattering model. A preliminary validation of the code obtained through a comparison with EGS4 and an experiment is presented, showing a satisfactory agreement.
A compton spectrometer to monitor the ELI-NP gamma beam energy Borgheresi, R.; Adriani, O.; Albergo, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Volume:
936
Journal Article
Peer reviewed
The ELI-NP facility (Extreme Light Infrastructure-Nuclear Physics) will deliver an intense and almost monochromatic gamma beam for frontier research in nuclear physics. Peculiar devices and ...techniques have been developed to measure and monitor the beam parameters during the commissioning and the operational phase. In this work we will present the Compton Spectrometer, designed to reconstruct the γ beam energy spectrum, by measuring the energy and the position of Compton scattered electrons. The energy and the angle of the scattered electron are measured by a High Purity Germanium detector and a double sided silicon strip detector. The associated photon is detected in coincidence with the electron by barium fluoride (BaF2) crystals for trigger purpose. In this work we report the status of the characterization carried out on the detectors composing the spectrometer.
•Compton spectrometer, designed to reconstruct the ELI-NP γ beam energy spectrum.•Energy of the scattered e− measured with a High Purity Germanium detector.•Scattered angle determined by a double sided silicon strip detector.•Scattered photon detected in coincidence by BaF2 crystals for trigger purpose.•Tests carried out on the components of the spectrometer are presented.
ELI–nuclear physics (NP) Gamma Beam System (GBS) is an intense and monochromatic gamma beam source based on inverse Compton interaction, currently being built in Bucharest, Romania. The gamma beam ...produced, with energy ranging from 0.2 to 20MeV, energy bandwidth 0.5% and flux of about 108photons/s, will be devoted to investigate a broad range of applications such as nuclear physics, astrophysics, material science and life sciences. The radiation produced by an inverse Compton interaction is not intrinsically monochromatic. In fact, the energy of the photons produced is related to the emission angle, therefore the energy bandwidth can be modified adjusting the collimation of the gamma beam. In order to define the optimal layout and evaluate the performance of a collimation system for the ELI–NP–GBS low-energy beamline (0.2–3.5MeV), a detailed Monte Carlo simulation activity has been carried out. The simulation, using Geant4 and MCNPX codes, included the transport of the gamma beam from the interaction point to the experimental area passing through vacuum pipes, vacuum chambers, collimation system and relative shielding. The effectiveness of the collimation system, in obtaining the required energy distribution and avoiding the contamination due to secondary radiation production, was evaluated. Also, the background radiation generated by collimation and the shielding layout have been studied.
PDF
