Breast cancer: imaging and radiotherapy with synchrotron radiation

The breast cancer is the most common cancer in woman worldwide. In this scenario, two aspects are very important: the early diagnosis and the efficacy of the care. The gold standard for the screening of breast cancer is the two-view mammography and the standard care includes surgery, usually coupled with chemotherapy or radiotherapy with 6-MV X-ray tangential beams from a linear accelerator. The problem of superimposition of tissue along the direction of the beam, which can make difficult the task of lesion detection in mammography, has led to the development of 3D techniques – such as Digital Breast Tomosynthesis (DBT) and Breast Computed Tomography (BCT) – which resolve the breast anatomy also in the longitudinal direction. In addition, in the last decades the use of phase-contrast (PhC) imaging techniques (which permit to detect the phase-shift of the X-ray beam in tissue) produced improvements in the detection of breast cancer. As regards adjuvant radiotherapy of breast cancer, an effective treatment has to guarantee the maximum sparing to the healty tissues, in particular to the skin. For this purpose, new techniques – such as IMRT, helical tomotherapy, VMAT – are under clinical investigation. Moreover, new kilovoltage rotational radiotherapy techniques with X-ray beam from orthovoltage X-ray tube as well as linear accelerator have been proposed. In this work, we investigated the use of the synchrotron radiation (SR) for both low-dose phase-contrast breast computed tomography (PhC-BCT) and breast rotational radiotherapy, via Monte Carlo simulations and measurements. Experiments were conducted at three different synchrotron radiation facilities: ELETTRA (Trieste, Italy), ESRF (Granoble, France), Australian Synchrotron (Melbourne, Australia). Phase contrast mammography on a cohort of patients was pioneered at ELETTRA in the last decade, showing the advantage of propagation based PhC imaging in producing higher conspicuity of breast masses; the ongoing projects at ELETTRA aim at devising a setup and a protocol for future computed tomography (CT) scans of the breast. The first part of the work, carried out in the framework of the SYRMA-CT/3D projects funded by INFN (National Institute for Nuclear Physics, Italy), showed the dosimetry measurements as well as the first imaging test of PhC-BCT at ELETTRA, carried out at 38 keV or lower energies. New dose metrics were introduced to take into account the partial breast irradiation envisaged for the exam; in addition, we carried out a characterization of dosimeters (TLD GR-200A and radiochromic film XR-QA2) to be employed for beam and phantom dosimetry. Finally, we showed the results of the first imaging test with a breast tissue specimen.In the second part of this PhD work, we demonstrated the feasibility of rotational breast radiotherapy with synchrotron radiation laying the foundations for the study of a new image-guided radiotherapy technique for breast cancer. This technique employs the same setup used for BCT but uses higher energies (60–120 keV) and higher intensity SR beams. The use of such low photon energies (with respect to megavoltage photon energies used in conventional radiotherapy) would provide a higher dose-enhancement when a radiosensitizing (e.g. gold nanoparticles) is used for breast radiotherapy. Possible applications of this technique could be the treatment of the small lesion and hypo-fractionated radiotherapy

The symmetric 3D organization of connective tissue around implant abutment: a key-issue to prevent bone resorption

Symmetric and well-organized connective tissues around the longitudinal implant axis were hypothesized to decrease early bone resorption by reducing inflammatory cell infiltration. Previous studies that referred to the connective tissue around implant and abutments were based on two-dimensional investigations; however, only advanced three-dimensional characterizations could evidence the organization of connective tissue microarchitecture in the attempt of finding new strategies to reduce inflammatory cell infiltration. We retrieved three implants with a cone morse implant–abutment connection from patients; they were investigated by high-resolution X-ray phase-contrast microtomography, cross-linking the obtained information with histologic results. We observed transverse and longitudinal orientated collagen bundles intertwining with each other. In the longitudinal planes, it was observed that the closer the fiber bundles were to the implant, the more symmetric and regular their course was. The transverse bundles of collagen fibers were observed as semicircular, intersecting in the lamina propria of the mucosa and ending in the oral epithelium. No collagen fibers were found radial to the implant surface. This intertwining three-dimensional pattern seems to favor the stabilization of the soft tissues around the implants, preventing inflammatory cell apical migration and, consequently, preventing bone resorption and implant failure. This fact, according to the authors’ best knowledge, has never been reported in the literature and might be due to the physical forces acting on fibroblasts and on the collagen produced by the fibroblasts themselves, in areas close to the implant and to the symmetric geometry of the implant itself

Energy response of GR-200A thermoluminescence dosemeters to CO-60 and to monoenergetic synchrotron radiation in the energy range 28-40 KEV

7noThe response of LiF:Mg,Cu,P thermoluminescence dosemeters (type GR-200A) to monoenergetic radiation of energy 28, 35, 38 and 40 keV was evaluated with respect to irradiation with a calibrated 60Co gamma-ray source. High-precision measurements of the relative air kerma response performed at the SYRMEP beamline of the ELETTRA synchrotron radiation facility (Trieste, Italy) showed a significant deviation of the average response to low-energy X-rays from that to 60Co, with an over-response from 6 % (at 28 keV) to 22 % (at 40 keV). These data are not consistent with literature data for these dosemeters, where model predictions gave deviation from unity of the relative air kerma response of about 10 %. The authors conclude for the need of additional determinations of the low-energy relative response of GR-200A dosemeters, covering a wider range of monoenergetic energies sampled at a fine energy step, as planned in future experiments by their group at the ELETTRA facility.Published online first 02 March 2015partially_openembargoed_20160302F. Emiro; F. Di Lillo; G. Mettivier; C. Fedon; R. Longo; G. Tromba; P. RussoF., Emiro; F., Di Lillo; G., Mettivier; Fedon, Christian; Longo, Renata; G., Tromba; P., Russ

The optical method based on gas injection overestimates leaf vulnerability to xylem embolism in three woody species

Plant hydraulic traits related to leaf drought tolerance like the water potential at turgor loss point (TLP) and the water potential inducing 50% loss of hydraulic conductance (P50), are extremely useful to predict potential impacts of drought on plants. While novel techniques allowed the inclusion of TLP in studies targeting a large group of species, fast and reliable protocols to measure leaf P50 are still lacking. Recently, the optical method coupled with the gas-injection (GI) technique has been proposed as a possibility to speed up P50 estimation. Here, we present a comparison of leaf optical vulnerability curves (OVc) measured in three woody species, namely F Acer campestre (Ac), Ostya carpinifolia (Oc) and Populus nigra (Pn), based on bench dehydration (BD) or gas-injection (GI) of detached branches. For Pn, we also compared optical data with direct micro-CT imaging in both intact saplings and cut shoots subjected to BD. Based on the BD e procedure, Ac, Oc and Pn had P50 values of -2.87, -2.47 and -2.11 MPa, respectively, while the GI procedure overestimated leaf vulnerability (2.68, 2.04 and 1.54 MPa for Ac, Oc and Pn, respectively). The overestimation was higher for Oc and Pn than for Ac, likely reflecting the species-specific e vessel lengths. According to micro-CT observations performed on Pn, the leaf midrib showed none or very few embolized conduits at -1.2 MPa, consistent with the OVc obtained with the BD procedure but at odds with that derived on the basis of GI. Overall, our data suggest that coupling the optical method with GI might not be a reliable technique to quantify leaf hydraulic vulnerability, since it could be affected by the ‘open-vessel’ artefact. Accurate detection of xylem embolism in the leaf vein network should be based on BD, preferably of intact up-rooted plants

Teaching with What you Are: The Importance of Teachers’ Positive Resources and of the Neuropsychopedagogical Training Envisioning the Future on Adolescents’ Well-Being. A Correlational and Analysis of Variance Study

The literature shows that teachers’ psychological characteristics can influence adolescents’ mental health. Additionally, neuropsychopedagogical interventions, like the Envisioning the Future (EF) training, can positively impact wellbeing. The study aims at: (i) exploring the relationships between teachers’ and students’ characteristics and (ii) investigating the impact of EF on students’ wellbeing. The sample consists of N = 113 Italian adolescents, whose data were matched with their teachers’ (N = 12). Participants completed validated self-report questionnaires on self-compassion, emotion regulation, resilience, and an ad-hoc scale of frequency of bullying episodes. Correlational analyses highlight that: teachers’ avoidance, social isolation, and self-judgment negatively correlate with the frequency with which students perceive bullying episodes; teachers’ self-kindness, optimism, and self-efficacy in regulating emotions positively correlate with the frequency with which the students’ perceive bullying; teachers’ cognitive focus positively correlates with students’ self-determination toward future decisions; students’ self-judgment negatively correlates with teachers’ resilience and self-efficacy in managing positive emotions, while it positively correlates with teachers’ avoidance. In addition, after EF training, students had improved in negative emotion regulation, frequency of perceiving bullying, common humanity, and self-determination. The study underscores the importance of the relationship between teachers’ and students’ resources and the impact of EF training on adolescents’ wellbeing

2022-RA-767-ESGO Machine learning to implement the accuracy of magnetic resonance imaging (MRI) in the detection of lymph node metastasis in patients with locally advance cervical cancer treated with neoadjuvant chemotherapy

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High resolution propagation-based lung imaging at clinically relevant X-ray dose levels

Absorption-based clinical computed tomography (CT) is the current imaging method of choice in the diagnosis of lung diseases. Many pulmonary diseases are affecting microscopic structures of the lung, such as terminal bronchi, alveolar spaces, sublobular blood vessels or the pulmonary interstitial tissue. As spatial resolution in CT is limited by the clinically acceptable applied X-ray dose, a comprehensive diagnosis of conditions such as interstitial lung disease, idiopathic pulmonary fibrosis or the characterization of small pulmonary nodules is limited and may require additional validation by invasive lung biopsies. Propagation-based imaging (PBI) is a phase sensitive X-ray imaging technique capable of reaching high spatial resolutions at relatively low applied radiation dose levels. In this publication, we present technical refinements of PBI for the characterization of different artificial lung pathologies, mimicking clinically relevant patterns in ventilated fresh porcine lungs in a human-scale chest phantom. The combination of a very large propagation distance of 10.7 m and a photon counting detector with [Formula: see text] pixel size enabled high resolution PBI CT with significantly improved dose efficiency, measured by thermoluminescence detectors. Image quality was directly compared with state-of-the-art clinical CT. PBI with increased propagation distance was found to provide improved image quality at the same or even lower X-ray dose levels than clinical CT. By combining PBI with iodine k-edge subtraction imaging we further demonstrate that, the high quality of the calculated iodine concentration maps might be a potential tool for the analysis of lung perfusion in great detail. Our results indicate PBI to be of great value for accurate diagnosis of lung disease in patients as it allows to depict pathological lesions non-invasively at high resolution in 3D. This will especially benefit patients at high risk of complications from invasive lung biopsies such as in the setting of suspected idiopathic pulmonary fibrosis (IPF)

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects