77 research outputs found
PROBING SYNCHROTRON RADIATION COHERENCE: THE HETERODYNE SPECKLE APPROACH
No full textIn this manuscript we describe a novel method to map the two-dimensional transverse coherence of an x-ray beam using the dynamical near-field speckles formed by scattering from colloidal particles. The method is suitable for live beam diagnostics, allowing time-resolved measurements
Measure of the transverse coherence of a self amplified spontaneous emission of a free electron laser with the heterodyne speckle method
No full textWe describe the method of Heterodyne Near Field Speckles (HNFS) for the characterization of spatial and temporal coherence of radiation. The method relies on the statistical properties of the speckle field produced by spherical particles randomly distributed and suspended in a fluid. We report preliminary results obtained with broadband light sources. We discuss the results obtained with the Self-Amplified Spontaneous Emission free electron laser SPARC LAB. This method will enable to calibrate and realize a diagnostics for the X-ray, broadband betatron radiation emitted in laser-plasma accelerators
Probing Transverse Coherence with the Heterodyne Speckle Approach: Overview and Perspectives
No full textAbstractThe properties of spatial coherence of radiation emitted by relativistic electrons is far from being trivial. Assessing the coherence of high-brilliance X-ray sources (3rd generation synchrotrons or free electron lasers) is of crucial importance for machine diagnostics, as well as in planning experiments exploiting coherent techniques. The Heterodyne Speckles method, firstly described by Alaimo et al. (2009), is a valuable alternative to standard methods (e.g. Young's interferometer) which 1) provides a direct measure of transverse coherence without any a-priori assumption, 2) provides a full 2D map of coherence, 3) is capable of one shot, time-resolved measures, 4) is scalable over a wide range of wavelengths. It relies upon the statistical analysis of radiation scattered by spherical particles randomly distributed and suspended in a fluid. Here we give an overview of this method, from the theoretical framework to the operating conditions to be adopted in order to obtain coherence measurements in several conditions
Probing the transverse coherence of an undulator X-ray beam using Brownian particles
No full textWe present a novel method to map the two-dimensional transverse coherence of an x-ray beam using
the dynamical near-field speckles formed by scattering from colloidal particles. Owing to the statistical
nature of the method, the coherence properties of synchrotron radiation from an undulator source is
obtained with high accuracy. The two-dimensional complex coherence function is determined at the
sample position and the imaging optical scheme further allowed us to evaluate the coherence factor at the
undulator output despite the aberrations introduced by the focusing optics
First detection of porcine circovirus type 2e in Europe
No full textPorcine circovirus 2 (PCV-2) infections are among the most economically important in swine farming. Because of the high evolutionary rate of PCV-2, several variants have emerged and are currently classified into several genotypes. However, only three (i.e. PCV-2a, PCV-2b, and PCV-2d) have a worldwide distribution, with other genotypes restricted to certain geographical regions and/or for limited time periods. Underdiagnosis or underreporting of these genotypes cannot be excluded. This is the first report of the detection and genetic characterisation of the PCV-2e genotype in Europe, from sows on a farm in Italy showing no clinical evidence of porcine circovirus disease. A follow-up study demonstrated persistent subclinical evidence of PCV-2e on the farm, at low frequency and viral load. This incidental finding emphasises the need for more intensive routine monitoring activities involving asymptomatic animals, coupled with DNA sequencing and data sharing. Considering the relevant genetic and phenotypic divergence of such genotypes, the actual efficacy of currently applied vaccines and diagnostic assays should be further evaluated
Ultra-Hypofractionation for Whole-Breast Irradiation in Early Breast Cancer: Interim Analysis of a Prospective Study
No full textWe report on the early clinical outcomes of a prospective series of early breast cancer (EBC) patients treated with ultra-hypofractionated post-operative whole-breast irradiation (WBI) after breast-conserving surgery (BCS) and axillary management. Primary endpoints were patient's compliance and acute toxicity. Secondary endpoints included physician-rated cosmesis and ipsilateral breast tumour recurrence (IBTR). Acute toxicity was evaluated at the end of WBI, 3 weeks and 6 months thereafter, according to the Common Terminology Criteria for Adverse Events (v. 5.0). Patients were treated between September 2021 and May 2022. The treatment schedule for WBI consisted of either 26 Gy in 5 fractions over one week (standard approach) or 28.5 Gy in 5 fractions over 5 weeks (reserved to elders). Inverse planned intensity-modulated radiation therapy (IMRT) was used employing a static technique. A total of 70 patients were treated. Fifty-nine were treated with the 26 Gy/5 fr/1 w and 11 with the 28.5 Gy/5 fr/5 ws schedule. Median age was 67 and 70 in the two groups. Most of the patients had left-sided tumours (53.2%) in the 26 Gy/5 fr/1 w or right-sided lesions (63.6%) in the 28.5 Gy/5 fr/5 ws group. Most of the patients had a clinical T1N0 disease and a pathological pT1pN0(sn) after surgery. Ductal invasive carcinoma was the most frequent histology. Luminal A intrinsic subtyping was most frequent. Most of the patients underwent BCS and sentinel lymph node biopsy and adjuvant endocrine therapy. All patients completed the treatment program as planned. Maximum detected acute skin toxicities were grade 2 erythema (6.7%), grade 2 induration (4.4%), and grade 2 skin colour changes. No early IBTR was observed. Ultra-hypofractionated WBI provides favourable compliance and early clinical outcomes in EBC after BCS in a real-world setting
Prevention of malignant seeding at drain sites after invasive procedures (surgery and/or thoracoscopy) by hypofractionated radiotherapy in patients with pleural mesothelioma
No full textIntroduction. Literature data show that mesothelioma cells can implant along the surgical pathway of invasive procedures such as thoracotomy and thoracoscopy. We investigated the use of hypofractionated radiotherapy for preventing such malignant seeding. Material and methods. Thirty-two consecutive patients diagnosed with pleural mesothelioma were included in the present retrospective study. All patients underwent surgery and/or thoracoscopy for diagnosis, staging or talc pleurodesis. They were treated with electron external beam radiation therapy (21 Gy in 3 fractions over 1 week), directed to the surgical pathway after the invasive procedure. After completion of radiation treatment, 20 of 32 patients (63%) underwent chemotherapy. Results. After a mean follow-up of 13.6 months (range 341) from the end of radiation therapy, no
patient had tumour progression in the treated area. The treatment was well tolerated, as only erythema grade I (Radiation Therapy Oncology Group, RTOG, scale) was noted in 11 patients. Seventeen patients died of disease with local progression after a mean survival time of 12.6 months (range 327); thirteen patients are alive with disease after a mean follow-up of 13.9 months (range 441); two patients are alive without evidence of disease after a mean follow-up of 16.50 months (range 6-27). Discussion. The present study shows the efficacy and safety of local radiotherapy in preventing malignant seeding after thoracoscopy in patients with pleural mesothelioma although larger prospective trials are probably still needed to validate this treatment approach
Voice quality after treatment for T1a glottic carcinoma--radiotherapy versus laser cordectomy
No full textThe purpose of this study was to assess the anatomic and functional outcomes and compare the voice quality in patients affected by T1a glottic carcinoma treated with curative intent with radiotherapy or laser cordectomy. Fifty-seven cases were analysed: 27 after curative
radiotherapy and 30 after laser cordectomy. All patients were studied with videolaryngostroboscopy, voice analysis by narrow spectrogram, and vocal parameters (Jitter, Shimmer, noise/harmonic ratio, and diplophonia). Videolaryngostroboscopy showed severe glottic inadequacy
in 25% of cases treated with radiation and insufficient compensation ‘ventricular band’ or ‘with arytenoid hyperadduction’ in 65% of cases after surgery. Severe dysphonia on the electro-acoustic analysis of voice was observed in 25% of cases after radiation and 70% after laser (pB/0.001). Fundamental frequency and vocal parameters showed more favourable results in the radiation group (pB/0.001). Voice assessment
showed better results after radiotherapy compared with laser cordectomy. Voice outcome should be carefully considered in the treatment decision for T1 glottic carcinoma
Delineation of target volume for radiotherapy of high-grade gliomas by 99m Tc-MIBI SPECT and MRI fusion
No full textBACKGROUND AND PURPOSE:
Computed tomography (CT) and magnetic resonance imaging (MRI) are traditionally used for treatment planning of high-grade glioma. 99m Tc-methoxy-isobutyl-isonitrile (MIBI) single-photon emission computed tomography (SPECT) showed high sensitivity and specificity in literature series. In the present study, it was investigated how the information provided by 99m Tc-MIBI SPECT and MRI fusion could affect target delineation for radiotherapy of high-grade glioma.
PATIENTS AND METHODS:
21 patients with high-grade glioma were studied by MRI and 99m Tc-MIBI SPECT imaging. The gross tumor volume (GTV) was outlined on MRI (MRI-GTV) and SPECT images (SPECT-GTV). Three additional volumes were analyzed: the (MRI+SPECT)-GTV representing the whole amount of MRI-GTV plus SPECT-GTV, the (MRI&SPECT)-GTV identified by the overlapping region of MRI-GTV and SPECT-GTV, and the (SPECT/MRI)-GTV identified by the extension of SPECT-GTV outside MRI-GTV.
RESULTS:
MRI contrast-enhanced and 99m Tc-MIBI SPECT-positive lesions were found in all 21 patients. The average SPECT-GTV was slightly larger than the average MRI-GTV, with greater difference for resected than for unresected cases. The average increment of (MRI+SPECT)-GTV compared to MRI-GTV was 33%, being significantly higher for resected than for unresected cases (p = 0.006).
CONCLUSION:
The fusion of 99m Tc-MIBI SPECT and MRI significantly affected the delineation of the target volume identified by MRI alon
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