SYnchrotron Radiation For MEdical Physics Beamline Research Articles

Multiscale biomedical imaging at the SYRMEP beamline of Elettra - Closing the gap between preclinical research and patient applications

Here we present the specifications and capabilities of the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline of the Italian Synchrotron “Elettra” in Trieste. SYRMEP was designed to provide X-ray imaging in an energy range that fits both biomedical research and clinical applications on patients. Additionally, SYRMEP covers a spatial resolution range of 100 μm down to 1 μm (1/50th the width of a human hair) with a comparably wide field-of-view (FOV), which enables studies in large specimens and therefore closes the gap between micro computed tomography (CT) in biomedical research and clinical CT imaging. Moreover, the possible long sample-to-detector distance allows for an effective use of free-propagation phase contrast that increases dose efficacy and soft-tissue contrast. These parameters and their function are further discussed on a set of examples of biomedical applications.

Quantitative pore network analysis and permeability evaluation of porous carbonate reservoir rocks using X-ray computed microtomography images

The texture and the morphology of the pore network exerts a primary control in the fluid storage and migration of geofluids within porous carbonates reservoirs. The architecture of the pore network of porous carbonates are highly variable because of primary depositional settings, diagenesis processes and deformation. This issue represents an important challenge for the characterization and exploitation plan of this type of reservoirs in different industries such as, hydrocarbon, ground water and geothermal energy. This type of rocks is widely studied because they represent important reservoirs for geofluids around the globe. However, there are few studies assessing the control exerted by the pore network properties (e.g. porosity, pore size distribution, connectivity, tortuosity) on the permeability. In this work the control exerted by the pore network on the storage and migration capacity in porous carbonates is evaluated by combining synchrotron X-ray computed microtomography (SR micro-CT) and computational fluid dynamics. The studied rock samples are mainly porous grainstones exposed in south and central Italy. Some samples may content deformation structures (i.e. deformation bands) or may be altered by diagenesis. Previous studies have reported permeability differences and significant variability of the in-situ hydrocarbon distribution in the studied rocks. The SR micro-CT imaging experiments were performed at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline (Elettra-Sincrotrone Trieste laboratory, Italy). This beamline was suitable for studying the rocks samples due to its nearly-parallel geometry and a high spatial coherence allowing the phase contrast effects to enhance the visibility of objects with similar linear attenuation coefficients. In this study, the selected spatial resolution of the images is variable (1.0-9.0 μm) depending on the grain size distribution of the rock sample. The SR micro-CT images were used for both performing a quantitative pore network analysis of the studied rock samples and performing computational fluid dynamics experiments. These experiments consist in simulating a pressure-driven flow by using the lattice-Boltzmann method (LBM) with multiple relaxation time (MRT) approach. This method generates viscosity-independent results of permeability. The permeability of the volume was calculated using Darcy’s law once steady conditions were reached. To evaluate isotropy, the results of permeability and the pore network properties were calculated in three dimensions. The results indicate that deformation and diagenetic processes may have and important impact on the pore network properties and therefore on storage (porosity) and migration (permeability) capacity of the studied rocks.

Synchrotron microtomography to evaluate effects of different polychemotherapy drugs on cortical bone structure

Purpose: To determine the effects of different polychemotherapy drugs on cortical bone structure, the femur diaphysis of rats were treated with two different chemotherapy drugs, AC (doxorubicin + cyclophosphamide) and TC (docetaxel + cyclophosphamide), and evaluated by 3D morphological analysis using synchrotron radiation microtomography.Materials and methods: Wistar rats were classified into three groups. One group received doses of docetaxel and cyclophosphamide (G1) – TC regimen; a second group received doses of doxorubicin and cyclophosphamide (G2) – AC regimen; while a control group (G0) received no further treatment. 3D tomographic images of the rats’ femurs were obtained at the SYRMEP (Synchrotron Radiation for Medical Physics) beamline at the ELETTRA Synchrotron Laboratory in Trieste, Italy, using monochromatic X-rays with resolution of 9 μm.Results: It could be shown that the treatment caused significant differences in morphological parameters measured from the 3D images of femur diaphysis of rats, among the studied groups, complementing a previous study using stereological methods, biochemistry and electron microscopy.Conclusions: Our results indicate that the same process of osteoporosis caused by advancing age might occur in young women treated with docetaxel + cyclophosphamide (TC) and doxorubicin + cyclophosphamide (AC). 3D microtomography was shown to be an outstanding technique for bone analysis.

Analysis of cortical bone porosity using synchrotron radiation microtomography to evaluate the effects of chemotherapy

Abstract Microporosities play important biologic and mechanical roles on health. One of the side effects caused by some chemotherapy drugs is the induction of amenorrhea, temporary or not, in premenopausal women, with a consequent decrease in estrogen production, which can lead to cortical bone changes. In the present work, the femur diaphysis of rats treated with chemotherapy drugs were evaluated by 3D morphometric parameters using synchrotron radiation microtomography. Control animals were also evaluated for comparison. The 3D tomographic images were obtained at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at the ELETTRA Synchrotron Laboratory in Trieste, Italy. Results showed significant differences in morphometric parameters measured from the 3D images of femur diaphysis of rats.

Synchrotron based planar imaging and digital tomosynthesis of breast and biopsy phantoms using a CMOS active pixel sensor

The SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at Elettra is performing the first mammography study on human patients using free-space propagation phase contrast imaging. The stricter spatial resolution requirements of this method currently force the use of conventional films or specialized computed radiography (CR) systems. This also prevents the implementation of three-dimensional (3D) approaches. This paper explores the use of an X-ray detector based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology as a possible alternative, for acquisitions both in planar and tomosynthesis geometry.Results indicate higher quality of the images acquired with the synchrotron set-up in both geometries. This improvement can be partly ascribed to the use of parallel, collimated and monochromatic synchrotron radiation (resulting in scatter rejection, no penumbra-induced blurring and optimized X-ray energy), and partly to phase contrast effects. Even though the pixel size of the used detector is still too large – and thus suboptimal – for free-space propagation phase contrast imaging, a degree of phase-induced edge enhancement can clearly be observed in the images.

Synchrotron radiation X-ray microtomography and histomorphometry for evaluation of chemotherapy effects in trabecular bone structure

Three-dimensional microtomography has the potential to examine complete bones of small laboratory animals with very high resolution in a non-invasive way. One of the side effects caused by some chemotherapy drugs is the induction of amenorrhea, temporary or not, in premenopausal women, with a consequent decrease in estrogen production, which can lead to bone changes. In the present work, the femur heads of rats treated with chemotherapy drugs were evaluated by 3D histomorphometry using synchrotron radiation microcomputed tomography. Control animals were also evaluated for comparison. The 3D tomographic images were obtained at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at the Elettra Synchrotron Laboratory in Trieste, Italy. Results showed significant differences in morphometric parameters measured from the 3D images of femur heads of rats in both analyzed groups.

Phase-Contrast Mammography at the SYRMEP Beamline of Elettra

At the SYnchrotron Radiation for MEdical Physics (SYRMEP) beamline of Elettra, a widespread research activity in bio-medical imaging has been developed since 1997 [1]. The core program carried out by the SYRMEP research team concerns the use of synchrotron radiation (SR) for mammography in the effort of improving image diagnostic quality innovating the imaging technique and the detection system.

Evaluation of charge -sharing effects on the spatial resolution of the PICASSO detector

A double -layer “edge-on” silicon microstrip detector has been designed and realized in the frame of the PICASSO (Phase Imaging for Clinical Application with Silicon detector and Synchrotron radiatiOn) project at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline of Elettra (Trieste, Italy). The detector meets the requirements for synchrotron radiation mammography with patients inregarding: (a) size, since it covers the full beam width (210 mm); (b) spatial resolution, determined by the 0.05 mm strip pitch; (c) single-photon counting capabilities, because it is able to handle more than 10 6 photons/(pixel×s); (d) contrast resolution, thanks to a threshold trim DAC that equalizes the channel sensitivity; (e) efficiency, due to the high absorption in the 15–20 mm sensor depth. Experimental measurements evidence charge sharing, though not compromising the spatial resolution.

Clinical mammography at the SYRMEP beam line

The synchrotron radiation (SR) clinical mammography, using as detector a commercial screen-film system, is a further crucial step of the SYRMEP (Synchrotron Radiation for Medical Physics) Project. In March and April of this year, mammographic examinations on nine patients have been carried out with X-rays from ELETTRA, the SR laboratory in Trieste, Italy. The facility for Phase Contrast (PhC) SR mammography is now operative in patient mode and is used for patient examinations, producing breast images in different projections. The entire procedure is automated and is able to achieve the correct exposure on the film taking into consideration the requested limits on the applied dose, as a function of the thickness and glandularity of the breast. The SR mammography shows a higher spatial resolution and contrast detail visibility, in comparison with the conventional analog or digital mammography, with a comparable or lower dose. In some cases of these first nine patients, the radiologists have clarified the ambiguity of the previous examinations. These preliminary results are encouraging and a complete evaluation of the clinical impact of the new method is in progress.

A digital detector for breast computed tomography at the SYRMEP beamline

A silicon strip detector in edge on configuration with a single photon counting read-out electronics was developed for the MATISSE (MAmmographic and Tomographic Imaging with Silicon detectors and Synchrotron radiation at Elettra) project. MATISSE is an experiment aiming at a pre-clinical phase of breast computed tomography examinations at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at the Elettra synchrotron light source in Trieste (Italy). A monochromatic beam in the energy range 8–35 keV is available at SYRMEP. The MATISSE detector is side illuminated, thus allowing direct conversion of X-rays with a high efficiency. The read-out electronics operates in single photon counting mode, maximizing the contrast resolution of the images. Thanks to the characteristics of the radiation spectrum and to the high efficiency of the detector, the dose delivered in a tomographic examination results comparable to the one delivered in planar conventional mammography. Detector prototypes have been assembled and tested with promising results that will be presented in this contribution.

Medical applications of synchrotron radiation at the SYRMEP beamline of ELETTRA

The main purpose of the SYRMEP (SYnchrotron Radiation for MEdical Physics) research team is the investigation and development of innovative techniques for medical imaging. A dedicated beamline has been built at ELETTRA to evaluate the effectiveness of synchrotron-based techniques in medical radiology with particular interest to mammography, and more in general, to the imaging of biological and biomedical samples, either in planar or tomographic set-ups. Taking advantage of the high intensity and high spatial coherence of Synchrotron Radiation (SR), phase sensitive techniques such as Phase Contrast (PhC) and Diffraction Enhanced Imaging (DEI) can be applied. After successful studies carried out on test objects and in vitro samples, the research in mammography is aiming at in vivo clinical trials. For this purpose, the layout of the SYRMEP beamline has been substantially modified and the safety system has been completely redesigned to guarantee the compliance with current radiation protection guidelines. In the present paper, the main characteristics of the beamline and an overview of the results obtained in different contexts of biomedical imaging are presented. Moreover, the status of the project for clinical mammography is outlined.