114 research outputs found
Recent advances in transurethral resection of bladder tumors
Transurethral resection of the bladder tumor (TURBT) is a standard procedure in bladder cancer management. TURBT has two main goals: to resect completely all the tumor lesions in healthy tissues and to provide high-quality specimen to facilitate accurate diagnosis. To achieve these goals, urologists make use of several options to maximize the efficiency of the procedure. To make tumor detection as effective as possible, the European Association of Urology guidelines recommend using enhanced visualization methods such as photodynamic diagnostics (PDD) and narrow-band imaging (NBI). Novel en bloc technique enables one to provide specimens of a higher quality and to increase recurrence-free survival. Also, the use of new energy sources such as lasers helps to decrease bleeding and prevent several complications after TURBT, e.g., obturator nerve reflex and bladder perforation. This article summarizes the options available to enhance the TURBT procedure and reports on the latest data on their feasibility for clinical practice
Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND
Radioactive isotopes produced through cosmic muon spallation are a background
for rare-event detection in detectors, double--decay experiments,
and dark-matter searches. Understanding the nature of cosmogenic backgrounds is
particularly important for future experiments aiming to determine the pep and
CNO solar neutrino fluxes, for which the background is dominated by the
spallation production of C. Data from the Kamioka liquid-scintillator
antineutrino detector (KamLAND) provides valuable information for better
understanding these backgrounds, especially in liquid scintillators, and for
checking estimates from current simulations based upon MUSIC, FLUKA, and
GEANT4. Using the time correlation between detected muons and neutron captures,
the neutron production yield in the KamLAND liquid scintillator is measured to
be . For other isotopes,
the production yield is determined from the observed time correlation related
to known isotope lifetimes. We find some yields are inconsistent with
extrapolations based on an accelerator muon beam experiment.Comment: 16 pages, 20 figure
Neutron production by cosmic-ray muons at shallow depth
The yield of neutrons produced by cosmic ray muons at a shallow depth of 32
meters of water equivalent has been measured. The Palo Verde neutrino detector,
containing 11.3 tons of Gd loaded liquid scintillator and 3.5 tons of acrylic
served as a target. The rate of one and two neutron captures was determined.
Modeling the neutron capture efficiency allowed us to deduce the total yield of
neutrons neutrons per muon
and g/cm. This yield is consistent with previous measurements at similar
depths.Comment: 12 pages, 3 figure
A New Approach for Split Renal Function Assessment Based on 3D-Models Generated from Contrast-enhanced Multi-slice Computed Tomography (Msct) Scans and Mathematical Analysis: A Pilot Study
Introduction: Instrumental methods of examination may alter the course of treatment and patients’ management: from minimally invasive nephron-sparing procedures to radical operations. Objective:to present preliminary data on split kidney function assessment (in a kidney volume, e.g. segment) in patients with urological diseases.Materials and methods: A prospective study was launched in aResearch Institute for Uronephrology and Reproductive Health from November, 2015 to February, 2017. 31 patients were enrolled into the study: 15 with stone kidney disease, 2 with kidney anomalies, 14 with renal tumors. Contrast-enhanced CT with 3D-models andmathematical analysis were performed in all patients. Correlation between CT-based and renal scintigraphy-based measures of split renal function was estimated.
Results: CT-based methods for the calculation of split renal function with 3D-models showed correlation with renal scintigraphy (p<0.004, ttest). Conclusion: A new approach for split kidney function assessment based on contrast-enhanced CT with 3D-models and mathematical analysis allows for both acquiring detailed data on clinical anatomy and evaluation of renal function to promote preoperative decision-making
On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements
For the first time a complete set of the most recent direct data on primary
cosmic ray spectra is used as input into calculations of muon flux at sea level
in wide energy range GeV. Computations have been performed
with the CORSIKA/QGSJET and CORSIKA/VENUS codes. The comparison of the obtained
muon intensity with the data of muon experiments shows, that measurements of
primary nuclei spectra conform to sea level muon data only up to several tens
of GeV and result in essential deficit of muons at higher energies. As it
follows from our examination, uncertainties in muon flux measurements and in
the description of nuclear cascades development are not suitable to explain
this contradiction, and the only remaining factor, leading to this situation,
is underestimation of primary light nuclei fluxes. We have considered
systematic effects, that may distort the results of the primary cosmic ray
measurements with the application of the emulsion chambers. We suggest, that
re-examination of these measurements is required with the employment of
different hadronic interaction models. Also, in our point of view, it is
necessary to perform estimates of possible influence of the fact, that sizable
fraction of events, identified as protons, actually are antiprotons. Study of
these cosmic ray component begins to attract much attention, but today nothing
definite is known for the energies GeV. In any case, to realize whether
the mentioned, or some other reasons are the sources of disagreement of the
data on primaries with the data on muons, the indicated effects should be
thoroughly analyzed
Pion and neutron production by cosmic-ray muons underground
The production of positive pions and neutrons by cosmic muons at underground
sites of various depths is investigated. We first test the equivalent photon
method in the particular case of excitation by the muon. We find that
this method, when it neglects the momentum dependence of the transverse
response, reproduces remarkably well the theoretical muon cross-section. This
success has lead us to apply the method to higher energies, where it has not
been tested. We evaluate in this way the production of positive pions in liquid
scintillator from known photo-absorption cross-sections. At a shallow depth of
20 meters our estimate reproduces the measurement. As for the neutron emission,
we include the obvious sources, such as the giant-resonance excitation, the
quasi-deuteron process, the quasi- free pion production as well as neutrons
emitted following pion capture. Our evaluation underestimates the number of
neutrons produced and finds a too weak dependence on the depth. This suggests
that secondary neutron production is important at all depths.Comment: 29 pages, late
Upper Limit on the Prompt Muon Flux Derived from the LVD Underground Experiment
We present the analysis of the muon events with all muon multiplicities
collected during 21804 hours of operation of the first LVD tower. The measured
depth-angular distribution of muon intensities has been used to obtain the
normalization factor, A, the power index, gamma, of the primary all-nucleon
spectrum and the ratio, R_c, of prompt muon flux to that of pi-mesons - the
main parameters which determine the spectrum of cosmic ray muons at the sea
level. The value of gamma = 2.77 +/- 0.05 (68% C.L.) and R_c < 2.0 x 10^-3 (95%
C.L.) have been obtained. The upper limit to the prompt muon flux favours the
models of charm production based on QGSM and the dual parton model.Comment: 10 pages, 4 figures, RevTex. To appear in Phys. Rev.
Retrospective analysis of prostate cancer detection using mpMR/US-fusion and cognitive biopsy
Introduction. Transrectal biopsy under US-control has been standard diagnostic method for prostate cancer (PCa) detection for over 30 years. However, TRUS-guided biopsy is not without well-known drawbacks. MR-targeted biopsy methods were proposed to eliminate the drawbacks and improve detection rate of clinically significant Pca. Cognitive and mpMR/US-fusion biopsies have become the most widely used MR-targeted biopsies. However, there are contradictory data on detection of clinically significant Pca when comparing mpMR/US-fusion and cognitive biopsies.Objective. To compare the detection rate of clinically significant prostate cancer performing cognitive and mpMR/US-fusion biopsies.Materials and methods. Inclusion criteria: PSA > 2.0 ng/ml and/or a positive DRE, and/or a suspicious lesion on TRUS, and PI-RADSv2.1 score ≥ 3. The outcomes evaluated are the detection of clinically significant Pca (ISUP ≥ 2), the overall PСa detection, the detection of clinically insignificant Pca, histological yield (proportion of positive cores, maximum cancer core length).Results. Retrospective data analysis was performed: cognitive biopsy was performed in 102 patients and mpMR/US-fusion biopsy in 176 patients. The median age was 63 years, prostate volume 46 cc. The median PSA was 6.4 ng/ml in the mpMR/US-fusion and 6.7 ng/ml in the cognitive biopsy group. MpMR/US-fusion and cognitive biopsies were comparable about the detection rate of clinically significant (30.3% vs 25.0%; p=0.329) and overall Pca detection rate (50.5% and 42.1%; p = 0.176). It was detected to be less clinically insignificant Pca in the cognitive biopsy group (11.8% vs. 25.5%; p = 0.007). The proportion of positive cores (30.5% and 29.5% respectively; p = 0.754) and maximum cancer core length (6.6 mm vs 7.6 mm; p = 0.320) were equal when comparing cognitive and mpMR/US-fusion biopsies. The proportion of positive cores with clinically significant Pca was higher in the cognitive biopsy group (18.6% vs 13.1%; p = 0.029).Conclusion. Both cognitive and mpMR/US-fusion biopsies are equally accurate for clinically significant Pca detection. Therefore, cognitive biopsy may be an alternative to mpMR/US-fusion biopsy in hospitals where mpMR/US-fusion technology is not currently available
- …