460 research outputs found
Is It Time to Call Time on Bone Marrow Biopsy for Staging Ewing Sarcoma (ES)?
Primary malignant bone sarcomas are rare and Ewing sarcoma (ES), along with osteosarcoma, predominates in teenagers and young adults. The well-established multimodality treatment incorporates systemic chemotherapy with local control in the form of surgery, with or without radiation. The presence and extent of metastases at diagnosis remains the most important prognostic factor in determining patient outcome; patients with skeletal metastases or bone marrow infiltration having a significantly worse outcome than those with lung metastases alone. There is, however, no accepted staging algorithm for ES. Large cooperative groups and national guidelines continue to advocate bone marrow biopsy (BMB) for staging but functional imaging techniques, such as 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) with computerised tomography (CT) have been increasingly used for staging cancers and whole-body magnetic resonance imaging (WB-MRI) for staging skeletal metastases. This review outlines the current literature, from which we conclude that BMB is no longer required for the staging of ES as it does not influence the standard of care management. BMB may, however, provide prognostic information and insights into the biology of ES in selected patients on prospective clinical trials
Improving Outcomes After Relapse in Ewing's Sarcoma: Analysis of 114 Patients From a Single Institution
The outcome for patients with relapsed Ewing's sarcoma is poor. A retrospective analysis was carried out to identify factors associated with improved survival. Between 1992 and 2002, 114 patients presented with relapsed or progressive disease. Median time to progression/relapse was 13 months (range, 2â128). Treatment at relapse included high dose treatment (HDT) in 29 patients, and surgery or definitive radiotherapy in 29. 2 and 5-year post relapse survival (PRS) was 23.5% and 15.2%, respectively. In multivariate analysis, the most significant factors associated with improved survival were disease confined locally or to the lungs (2-year PRS, 40% versus 6%; P < .001), relapse > 18 months from diagnosis (2-year PRS, 53% versus 8%; P < .001), HDT at relapse (2-year PRS, 62% versus 11%; P < .001), and surgery and/or radiotherapy at relapse (2-year PRS, 51% versus 14%; P < .001). First treatment failure in Ewing's sarcoma is mostly fatal. Improved survival can be achieved in selective patients with aggressive treatment. These improvements are confined to those without bone or bone marrow metastases
Identification and rejection of scattered neutrons in AGATA
Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were
measured in an AGATA experiment performed at INFN Laboratori Nazionali di
Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors
(12 36-fold segmented high-purity germanium crystals), placed at a distance of
50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment
was to study the interaction of neutrons in the segmented high-purity germanium
detectors of AGATA and to investigate the possibility to discriminate neutrons
and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were
used for a time-of-flight measurement, which gave an independent discrimination
of neutrons and gamma rays and which was used to optimise the gamma-ray
tracking-based neutron rejection methods. It was found that standard gamma-ray
tracking, without any additional neutron rejection features, eliminates
effectively most of the interaction points due to recoiling Ge nuclei after
elastic scattering of neutrons. Standard tracking rejects also a significant
amount of the events due to inelastic scattering of neutrons in the germanium
crystals. Further enhancements of the neutron rejection was obtained by setting
conditions on the following quantities, which were evaluated for each event by
the tracking algorithm: energy of the first and second interaction point,
difference in the calculated incoming direction of the gamma ray,
figure-of-merit value. The experimental results of tracking with neutron
rejection agree rather well with Geant4 simulations
Oscillations above the barrier in the fusion of 28Si + 28Si
Fusion cross sections of 28Si + 28Si have been measured in a range above the
barrier with a very small energy step (DeltaElab = 0.5 MeV). Regular
oscillations have been observed, best evidenced in the first derivative of the
energy-weighted excitation function. For the first time, quite different
behaviors (the appearance of oscillations and the trend of sub-barrier cross
sections) have been reproduced within the same theoretical frame, i.e., the
coupled-channel model using the shallow M3Y+repulsion potential. The
calculations suggest that channel couplings play an important role in the
appearance of the oscillations, and that the simple relation between a peak in
the derivative of the energy-weighted cross section and the height of a
centrifugal barrier is lost, and so is the interpretation of the second
derivative of the excitation function as a barrier distribution for this
system, at energies above the Coulomb barrier.Comment: submitted to Physics Letters
The new educational project Televascular Games during the Coronavirus Disease 2019 pandemic
Objective: To report methodology and first-year results of a new educational project called Televascular Games,â which took place during coronavirus disease 2019 pandemic. Methods: Complex aneurysmal aortic disease was discussed during a 2-hour competition webinar, according to three modalities. (1) Planning case competition (PCC): Two to four preoperative computed tomography angiography (CTA) scans of an already performed selected case were submitted for the competition. CTA scans were uploaded anonymously, without any reference to the center or the surgeon who performed the case. The competitor had to prepare a presentation of how he or she would have diagnosed, sized, planned, treated, and followed up the case, of the medical therapy and of the bail-out maneuvers. (2) Challenging case competition (CCC): The competitor elaborates a presentation of an already treated case concerning an aortic topic and discusses sizing, planning, treatment, possible bail-out maneuvers and obtained results. For the CCC and PCC, the competitors with the best score were preselected to present and discuss their plan during the webinars. (3) Quiz competition: Two to six CTA scans of already performed selected aortic cases were submitted for the competition. A quiz with multiple choice questions was answered by the competitors. The top four competitors were selected for the webinars and then they discussed the cases during the webinar. Finally, at the end of the case discussion, the effective case resolution and follow-up were shown. A final winner was voted via televoting, based on six preestablished criteria. The project was endorsed by different national and international societies. Results: Between October 2020 and December 2021, there were 12 Italian and 1 international webinars with 1695 participants overall (mean, 130; range, 86-177). Competitors were 54 years of age (mean, 27 years; range, 22-38 years). Two editions were CCCs, two quiz competitions, and nine PCCs. The reliability of the interobserver sizing of competitors was Îș = 0.43 and Îș = 0.62 for the proximal and distal sealing measurements respectively and very good (Îș = 0.88-0.95) in the evaluation of orientation of the vessels, presence of angulations, calcifications, and thrombus. The sizing discrepancy resulted in a significant variability of the planning (Îș = 0.45). The project ranked 9.6 on a 10-point rating scale by all the participants and competitors. Conclusions: The formula of gaming and collegial discussion of aortic cases herein reported has proved valid and attractive during coronavirus disease 2019 pandemic period. The variability of the results on sizing and planning suggested to confer with a second opinion, especially for less experienced surgeons
Fusion of 28Si + 28Si: oscillations above the barrier and the behavior down to 1ÎŒb
Fusion excitation functions of light heavy-ion systems show oscillatory structures above the Coulomb barrier, caused by resonances or due to the penetration of successive centrifugal barriers well separated in energy. In heavier systems, the amplitude of oscillations decreases and the peaks get nearer to each other. This makes the measurements very challenging. We have performed a first experiment for 28Si + 28Si, by measuring fusion cross sections (Ï) in an energy range of â15 MeV above the barrier, with a small ÎElab = 0.5 MeV step. Three regular oscillations are clearly observed, which are best revealed by plotting the energy-weighted derivative of the excitation function. The excitation function has been recently measured down to cross sections â€1ÎŒb with larger energy steps. Coupled-channel (CC) calculations based on a shallow potential in the entrance channel are able to reproduce the oscillations. A further analysis will provide a stringent test for the calculations, in particular for the choice of the ion-ion potential, because the subbarrier excitation function has to be reproduced as well. Coupled-channel (CC) calculations based on a shallow potential in the entrance channel are able to reproduce the oscillations. A further analysis will provide a stringent test for the calculations, in particular for the choice of the ion-ion potential, because the subbarrier excitation function has to be reproduced as well
Contrasting properties of particle-particle and hole-hole excitations in 206Tl and 210Bi nuclei
A complete-spectroscopy investigation of low-lying, low-spin states in the one-proton-hole and one-neutron-hole nucleus 206Tl has been performed by using thermal neutron capture and \u3b3-coincidence technique with the FIPPS Ge array at ILL Grenoble. The new experimental results, together with data for the one-proton-particle and one-neutron-particle nucleus 210Bi (taken from a previous study done at ILL in the EXILL campaign), allowed for an extensive comparison with predictions of shell-model calculations performed with realistic interactions. No phenomenological adjustments were introduced in the calculations. In 210Bi, state energies, transition multipolarities and decay branchings agree well with theory for the three well separated multiplets of states which dominate the low-lying excitations. On the contrary, in 206Tl significant discrepancies are observed: in the same energy region, six multiplets were identified, with a significant mixing among them being predicted, as a consequence of the smaller energy separation between the active orbitals. The discrepancies in 206Tl are attributed to the larger uncertainties in the determination of the off-diagonal matrix elements of the realistic shell-model interaction with respect to the calculated diagonal matrix elements, the only ones playing a major role in the case of 210Bi. The work points to the need of more advanced approaches in the construction of the realistic interactions
Transition probabilities in the X(5) candidate Ba
To investigate the possible X(5) character of 122Ba, suggested by the ground
state band energy pattern, the lifetimes of the lowest yrast states of 122Ba
have been measured, via the Recoil Distance Doppler-Shift method. The relevant
levels have been populated by using the 108Cd(16O,2n)122Ba and the
112Sn(13C,3n)122Ba reactions. The B(E2) values deduced in the present work are
compared to the predictions of the X(5) model and to calculations performed in
the framework of the IBA-1 and IBA-2 models
(n,γ) reactions on rare Ca isotopes: Valence-hole - Coreexcitation couplings in47Ca
Recent results on the structure of 47Ca will be presented. The nucleus of interest was populated via the cold-neutron capture 46Ca(n,\u3b3) reaction, on a rare 46Ca target, during the EXILL experimental campaign at the nuclear reactor of Institut Laue- Langevin in Grenoble. High-resolution \u3b3-ray spectroscopy, performed with a composite array of HPGe detectors, enabled the identification of new transitions deexciting states between the neutron-capture level and the ground state. Experimental data will be compared with a novel microscopic theoretical model, currently under development, specifically designed to describe the low-lying structure of odd-mass nuclei with one valence particle/hole outside a spherical doubly-magic core, using the Skyrme effective interaction self-consistently
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