An Addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water is presented for electron beams with energies between 4 MeV and 22 MeV ( ). This updated formalism allows simplified calibration procedures, including the use of calibrated cylindrical ionization chambers in all electron beams without the use of a gradient correction. New data are provided for electron beams based on Monte Carlo simulations.
View Article and Find Full Text PDFPurpose: Canadian radiation oncology professionals have a strong history of involvement in global oncology initiatives worldwide. This pan-Canadian survey-based study was conducted to determine the current level of engagement of Canadian radiation oncologists (ROs) and medical physicists (MPs) in global oncology initiatives and broaden the development of these activities.
Materials And Methods: This was a cross-sectional study.
J Appl Clin Med Phys
November 2023
Background: Magnetic resonance (MR)-guided radiation therapy provides capabilities to utilize high-resolution and real-time MR imaging before and during treatment, which is critical for adaptive radiotherapy. This emerging modality has been promptly adopted in the clinic settings in advance of adaptations to reference dosimetry formalism that are needed to account for the presence of strong magnetic fields. In particular, the influence of magnetic field on the uncertainty of parameters in the reference dosimetry equation needs to be determined in order to fully characterize the uncertainty budget for reference dosimetry in MR-guided radiation therapy systems.
View Article and Find Full Text PDFPurpose: To use a portable 4°C cooled MR-compatible water calorimeter to measure absorbed dose in a magnetic resonance-guided radiation therapy (MRgRT) system. Furthermore, to use the calorimetric dose results and direct cross-calibration to experimentally measure the combined beam quality and magnetic field correction factor ( ) of a clinically used reference-class ionization chamber placed under the same radiation field.
Methods: An Elekta Unity MR-linac (7 MV FFF, B = 1.
Purpose: To measure ionization chamber dose response as a function of the angle between magnetic field direction and ionization chamber orientation in magnetic resonance-guided radiation therapy (MRgRT) system, and to evaluate angular dependence of magnetic field correction factor for reference dosimetry.
Methods: Measurements were performed on an Elekta MR-linac that integrates a 1.5-T Philips MRI and a 7-MV FFF photon beam accelerator.
Efficacy of miniinvasive endoscopic mucosal resection (EMR) and submucosal dissection (SD) of the gut neuroendocrine tumours (NET) was studied up. In the clinic in 2009-2013 yrs 5 patients were treated for NET. In 2 patients it was localized in stomach, in 1--in duodenal ampulla, in 1--in terminal portion of ileum (TPI), in 1--in rectum.
View Article and Find Full Text PDFThe ratio of the Λb(0) baryon lifetime to that of the B(0) meson is measured using 1.0 fb(-1) of integrated luminosity in 7 TeV center-of-mass energy pp collisions at the LHC. The Λb(0) baryon is observed for the first time in the decay mode Λb(0)→J/ψpK-, while the B(0) meson decay used is the well known B(0)→J/ψπ+ K- mode, where the π+ K- mass is consistent with that of the K(*0)(892) meson.
View Article and Find Full Text PDFA search for the rare decays Bs(0)→μ+ μ- and B(0)→μ+ μ- is performed at the LHCb experiment. The data analyzed correspond to an integrated luminosity of 1 fb(-1) of pp collisions at a center-of-mass energy of 7 TeV and 2 fb(-1) at 8 TeV. An excess of Bs(0)→μ+ μ- signal candidates with respect to the background expectation is seen with a significance of 4.
View Article and Find Full Text PDFPhys Rev Lett
September 2013
The charmless decays B±→K± π+ π- and B±→K± K+ K- are reconstructed using data, corresponding to an integrated luminosity of 1.0 fb(-1), collected by LHCb in 2011. The inclusive charge asymmetries of these modes are measured as ACP(B±→K± π+ π-)=0.
View Article and Find Full Text PDFA search for heavy Majorana neutrinos produced in the B- → π+ μ- μ- decay mode is performed using 3 fb(-1) of integrated luminosity collected with the LHCb detector in pp collisions at center-of-mass energies of 7 and 8 TeV at the LHC. Neutrinos with masses in the range 250 to 5000 MeV and lifetimes from zero to 1000 ps are probed. In the absence of a signal, upper limits are set on the branching fraction B(B- → π+ μ- μ-) as functions of neutrino mass and lifetime.
View Article and Find Full Text PDFThe first measurement of the effective lifetime of the B(s)(0) meson in the decay B(s)(0) → Ds-Ds+ is reported using a proton-proton collision data set, corresponding to an integrated luminosity of 3 fb(-1), collected by the LHCb experiment. The measured value of the B(s)(0) → Ds-Ds+ effective lifetime is 1.379 ± 0.
View Article and Find Full Text PDFDecays of B(s)(0) and B(0) mesons into J/ψ π+π-π+π- final states, produced in pp collisions at the LHC, are investigated using data corresponding to an integrated luminosity of 3 fb-1 collected with the LHCb detector. B(s)(0) → J/ψ f1(1285) decays are seen for the first time, and the branching fractions are measured. Using these rates, the f1(1285) mixing angle between strange and nonstrange components of its wave function in the qq structure model is determined to be ±(24.
View Article and Find Full Text PDFPhys Rev Lett
January 2014
A study of indirect CP violation in D0 mesons through the determination of the parameter AΓ is presented using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0 fb(-1), collected with the LHCb detector and recorded at the center-of-mass energy of 7 TeV at the LHC. The parameter AΓ is the asymmetry of the effective lifetimes measured in decays of D0 and D0 mesons to the CP eigenstates K- K+ and π- π+.
View Article and Find Full Text PDFThe results of endoscopic resection of intestinal mucosa for colorectal neoplasia were analyzed. There were excised 148 colorectal lesions in 116 patients.The operation was performed, using submucosal injection of adrenaline solution with indigocarmine and the loop resection technique.
View Article and Find Full Text PDFThe laterally spreading colon tumors (LST) constitute a kind of flat superficial neoplasia, which may cause colorectal cancer. There was studied the efficacy of colonoscopy and chromoscopy, using indigocarmine and acetic acid in the LST diagnosis in 897 patients. In 85 (9.
View Article and Find Full Text PDFThe charmless decays B± → K+ K- π± and B± → π+ π- π± are reconstructed in a data set of pp collisions with an integrated luminosity of 1.0 fb(-1) and center-of-mass energy of 7 TeV, collected by LHCb in 2011. The inclusive charge asymmetries of these modes are measured to be A(CP)(B± → K+ K- π±) = -0.
View Article and Find Full Text PDFMeasurements of charm mixing parameters from the decay-time-dependent ratio of D0 → K+ π- to D0 → K- π+ rates and the charge-conjugate ratio are reported. The analysis uses data, corresponding to 3 fb(-1) of integrated luminosity, from proton-proton collisions at 7 and 8 TeV center-of-mass energies recorded by the LHCb experiment. In the limit of charge-parity (CP ) symmetry, the mixing parameters are determined to be x'2=(5.
View Article and Find Full Text PDFCharged particle multiplicities are studied in proton-proton collisions in the forward region at a centre-of-mass energy of [Formula: see text]TeV with data collected by the LHCb detector. The forward spectrometer allows access to a kinematic range of [Formula: see text] in pseudorapidity, momenta greater than [Formula: see text] and transverse momenta greater than [Formula: see text]. The measurements are performed using events with at least one charged particle in the kinematic acceptance.
View Article and Find Full Text PDFEur Phys J C Part Fields
May 2014
The polarisation of prompt [Formula: see text] mesons is measured by performing an angular analysis of [Formula: see text] decays using proton-proton collision data, corresponding to an integrated luminosity of 1.0[Formula: see text], collected by the LHCb detector at a centre-of-mass energy of 7 TeV. The polarisation is measured in bins of transverse momentum [Formula: see text] and rapidity [Formula: see text] in the kinematic region [Formula: see text] and [Formula: see text], and is compared to theoretical models.
View Article and Find Full Text PDFEur Phys J C Part Fields
May 2014
The lifetime of the [Formula: see text] meson is measured using semileptonic decays having a [Formula: see text] meson and a muon in the final state. The data, corresponding to an integrated luminosity of [Formula: see text], are collected by the LHCb detector in [Formula: see text] collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is [Formula: see text]where the first uncertainty is statistical and the second is systematic.
View Article and Find Full Text PDFPhys Rev Lett
November 2013
We present a measurement of form-factor-independent angular observables in the decay B(0)→K*(892)(0)μ(+)μ(-). The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment in pp collisions at a center-of-mass energy of 7 TeV.
View Article and Find Full Text PDFThe result of a search for the decay B(c)(+) → B(s)(0) π+ is presented, using the B(s)(0) → D(s)(-)π+ and B(s)(0) → J/ψ Ø channels. The analysis is based on a data sample of pp collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1 fb(-1) taken at a center-of-mass energy of 7 TeV, and 2 fb(-1) taken at 8 TeV. The decay B(c)(+) → B(s)(0)π+ is observed with significance in excess of 5 standard deviations independently in both decay channels.
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