8 research outputs found
Prognostic significance of normalized FDG-PET parameters in patients with multiple myeloma undergoing induction chemotherapy and autologous hematopoietic stem cell transplantation: a retrospective single-center evaluation
Purpose: The purpose of this study was to determine retrospectively, through a single-center evaluation, whether FDG PET-CT normalized semi-quantitative parameters may predict response to induction chemotherapy (iChT) and hematopoietic stem cell transplantation (HSCT), as well as disease progression and progression-free survival in multiple myeloma (MM) patients, thus becoming a tool of personalized medicine. Methods: Patients undergoing iChT and HSCT with baseline and post-treatment FDG PET-CTs from January 2008 to July 2015 were included. The following baseline and post-treatment parameters were obtained: SUVmax, SUVmean, SUVpeak, MTVsum, TLGsum, rPET (lesion SUVmax/liver SUVmax) and qPET (lesion SUVpeak/liver SUVmean). Baseline-to-post-treatment changes (Δ) were also calculated. Metabolic and clinical laboratory progression or response at follow-up were noted; time-to-metabolic-progression (TMP) was defined as the interval from post-treatment scan to eventual progression at follow-up FDG PET-CTs. Possible association between each functional parameter and metabolic/clinical-laboratory progression or response was determined. Kaplan-Meier curves allowed to depict the TMP trend according to FDG PET-CT parameters. Results: Twenty-eight patients were included. Significantly higher ΔrPET and ΔqPET values were observed in ten patients with “metabolic response”, with respect to 18 patients having “metabolic progression” (median 0.62 [IQR 0.32 – 1.34] vs median 0.00 [IQR -0.25 – 0.49] for ΔrPET; P = 0.045; median 0.51 [IQR 0.32 – 1.13] vs median 0.00 [IQR -0.31 – 0.67] for ΔqPET; P = 0.035). Neither normalized nor non normalized parameters differed significantly between the 20 patients with “clinical-laboratory response” and the eight patients with “clinical-laboratory progression”. ΔrPET value lower than 0.38 and ΔqPET value lower than 0.27 predicted a significantly shorter TMP (P = 0.003 and P = 0.005, respectively). Conclusions: Normalized semi-quantitative parameters are effective in predicting persistent response to treatment and shorter TMP in patients with MM undergoing iChT and HSCT
Cross sections for the γp→K*+Λ and γp→K*+Σ0 reactions measured at CLAS
The first high-statistics cross sections for the reactions γp→K*+Λ and γp→K*+Σ0 were measured using the CLAS detector at photon energies between threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. Differential cross sections are presented over the full range of the center-of-mass angles, and then fitted to Legendre polynomials to extract the total cross section. Results for the K*+Λ final state are compared with two different calculations in an isobar and a Regge model, respectively. Theoretical calculations significantly underestimate the K*+Λ total cross sections between 2.1 and 2.6 GeV, but are in better agreement with present data at higher photon energies
Observation of beam spin asymmetries in the process ep→e^{'}π^{+}π^{-}X with CLAS12
The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function G_{1}^{⊥}. A clear sign change is observed around the ρ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark
Prognostic significance of normalized FDG-PET parameters in patients with multiple myeloma undergoing induction chemotherapy and autologous hematopoietic stem cell transplantation: a retrospective single-center evaluation
Double polarisation observable G for single pion photoproduction from the proton
We report measurements of and meson photoproduction from longitudinally spin-polarised protons by an energy tagged (0.73-2.3 GeV) and linearly polarised photon beam. A close to complete solid angle coverage for the reaction products was provided by the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The double-polarisation observable is extracted from Maximum Likelihood fits to the data, enabling the first accurate determination for the reaction , while also significantly extending the kinematic coverage for . This large data set provides an important constraint on the properties and spectrum of excited nucleon states decaying to Nπ in the mass range from 1.4 to 2.2 GeV, as well as for background (non-resonant) photoproduction processes. The considerable improvement achieved in the description of the observable within the SAID and Bonn-Gatchina approaches after implementation of our data, illustrates that the partial-wave analyses now significantly extend the knowledge on Nπ photoproduction amplitudes at GeV. A partial-wave analysis using the new high-precision data set has a large impact on the extracted properties of high-spin nucleon excited states
12C(e,e'pN) measurements of short range correlations in the tensor-to-scalar interaction transition region
High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the 12C and 12C reactions (where N is either n or p), at high- and . The data span a missing-momentum range of 300–1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon (NN) interaction models. This agreement suggests that the measured high missing-momentum protons up to 1000 MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured 12C / 12C and 12C / 12C cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor NN interaction at ∼400 MeV/c to an isospin-independent scalar interaction at high-momentum around ∼800 MeV/c as predicted by theoretical calculation
Photoproduction of the f_{2}(1270) meson using the CLAS detector
The quark structure of the f_{2}(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq[over ¯]) resonance with quantum numbers J^{PC}=2^{++}. Recently, it was proposed that the f_{2}(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π^{+}π^{-}, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π^{0}π^{0}p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f_{2}(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations
Photoproduction of η mesons off the proton for 1.2<Eγ<4.7GeV using CLAS at Jefferson Laboratory
Photoproduction cross sections are reported for the reaction
γ
p
→
p
η
using energy-tagged photons and the CLAS spectrometer at Jefferson Laboratory. The
η
mesons are detected in their dominant charged decay mode,
η
→
π
+
π
−
π
0
, and results on differential cross sections are presented for incident photon energies between 1.2 and 4.7 GeV. These new
η
photoproduction data are consistent with earlier CLAS results but extend the energy range beyond the nucleon resonance region into the Regge regime. The normalized angular distributions are also compared with the experimental results from several other experiments, and with predictions of
η
-MAID 2018 and the latest solution of the Bonn-Gatchina coupled-channel analysis. Differential cross sections
d
σ
/
d
t
are presented for incident photon energies
E
γ
>
2.9
GeV
(
W
>
2.5
GeV
), and compared with predictions which are based on Regge trajectories exchange in the
t
-channel (Regge models). The data confirm the expected dominance of
ρ
,
ω
vector-meson exchange in an analysis by the Joint Physics Analysis Center