Split-bolus single-phase versus single-bolus split-phase CT acquisition protocols for staging in patients with testicular cancer: A retrospective study

INTRODUCTION

Computed tomography (CT) imaging has become indispensable in the management of medical oncology patients. Risks associated with high cumulative effective dose (CED) are relevant in testicular cancer patients. Split-bolus protocols, whereby the contrast medium injection is divided into two, followed by combining the required phase images in a single scan acquisition has been shown to provide images of comparable image quality and less radiation dose compared to single-bolus split-phase CT for various indications. We retrospectively evaluated the performance of split-bolus and single-bolus protocols in patients having follow-up CT imaging for testicular cancer surveillance.

METHODS

45 patients with testicular cancer undergoing surveillance CT imaging of the thorax, abdomen, and pelvis who underwent split-bolus and single-bolus protocols were included. Quantitative image quality analysis was conducted by placing region of interests in pre-defined anatomical sub-structures within the abdominal cavity. The signal-to-noise ratio (SNR) and radiation dose in the form of dose length product (DLP) and effective dose (ED) were recorded.

RESULTS

The DLP and ED for the single-bolus, split-phase acquisition was 506 ± 89 mGy cm and 7.59 ± 1.3 mSv, respectively. For the split-bolus, single-phase acquisition, 397 ± 94 mGy∗cm and 5.95 ± 1.4 mSv, respectively (p < 0.000). This represented a 21.5 % reduction in radiation dose exposure. The SNR for liver, muscle and fat for the single-bolus were 7.4, 4.7 and 8, respectively, compared to 5.5, 3.8 and 7.4 in the split-bolus protocol (p < 0.001).

CONCLUSION

In a testicular cancer patient cohort undergoing surveillance CT imaging, utilization of a split-bolus single-phase acquisition CT protocol enabled a significant reduction in radiation dose whilst maintaining subjective diagnostic acceptability.

IMPLICATIONS FOR PRACTICE

Use of split-bolus, single-phase acquisition has the potential to reduce CED in surveillance of testicular cancer patients.

Thermodynamics of Highly Interacting Blend PCHMA/dPS by TOF-SANS

We investigate the thermodynamics of a highly interacting blend of poly(cyclohexyl methacrylate)/deuterated poly(styrene) (PCHMA/dPS) with small-angle neutron scattering (SANS). This system is experimentally challenging due to the proximity of the blend phase boundary (>200 °C) and degradation temperatures. To achieve the large wavenumber q-range and flux required for kinetic experiments, we employ a SANS diffractometer in time-of-flight (TOF) mode at a reactor source and ancillary microscopy, calorimetry, and thermal gravimetric analysis. Isothermal SANS data are well described by random-phase approximation (RPA), yielding the second derivative of the free energy of mixing (G″), the effective interaction (χ̅) parameter, and extrapolated spinodal temperatures. Instead of the Cahn-Hilliard-Cook (CHC) framework, temperature (T)-jump experiments within the one-phase region are found to be well described by the RPA at all temperatures away from the glass transition temperature, providing effectively near-equilibrium results. We employ CHC theory to estimate the blend mobility and G″(T) conditions where such an approximation holds. TOF-SANS is then used to precisely resolve G″(T) and χ̅(T) during T-jumps in intervals of a few seconds and overall timescales of a few minutes. PCHMA/dPS emerges as a highly interacting partially miscible blend, with a steep dependence of G″(T) [mol/cm³] = -0.00228 + 1.1821/T [K], which we benchmark against previously reported highly interacting lower critical solution temperature (LCST) polymer blends.

Uniaxial polarization analysis of bulk ferromagnets: theory and first experimental results

On the basis of Brown's static equations of micromagnetics, the uniaxial polarization of the scattered neutron beam of a bulk magnetic material is computed. The approach considers a Hamiltonian that takes into account the isotropic exchange interaction, the antisymmetric Dzyaloshinskii–Moriya interaction, magnetic anisotropy, the dipole–dipole interaction and the effect of an applied magnetic field. In the high-field limit, the solutions for the magnetization Fourier components are used to obtain closed-form results for the spin-polarized small-angle neutron scattering (SANS) cross sections and the ensuing polarization. The theoretical expressions are compared with experimental data on a soft magnetic nanocrystalline alloy. The micromagnetic SANS theory provides a general framework for polarized real-space neutron methods, and it may open up a new avenue for magnetic neutron data analysis on magnetic microstructures.

Superchaotropic nano-ions as foam stabilizers

HYPOTHESIS

Weakly hydrated nanometric ions, called superchaotropes, were recently shown to adsorb strongly to non-ionic surfaces affecting drastically the surface's physical-chemical properties due to a charging effect. Superchaotropic ions could serve as stabilizing agents for non-ionic colloidal systems, such as non-ionic surfactant foams.

EXPERIMENTS

We study foams of the non-ionic surfactant BrijO10 (C_18:1E₁₀) without and in presence of the superchaotropic Keggin-ion SiW₁₂O₄₀^4- (SiW). The foams are investigated under free drainage conditions by image analysis and conductimetry to reveal the effect of SiW on the foam stability, liquid drainage, and bubble size. Additionally, small angle neutron scattering on the same foams, but in a dry quasi-stationary state, provides insight into effects of SiW on the foam films.

FINDINGS

SiW strongly stabilizes non-ionic surfactant foams at millimolar concentrations by inducing electrostatic repulsions between foam film interfaces resulting in thicker and monodisperse foam films. A similar effect is observed with the ionic surfactant sodium dodecylsulfate (SDS) but to a lesser extent and with a different mechanism. At the foam films' interface, SiW adsorbs to the polar non-ionic surfactant heads driven by the superchaotropic effect whereas DS^- anchors between non-ionic surfactant alkyl chains by the hydrophobic effect. The potential of superchaotropic ions as foam stabilizers is herein demonstrated.

Three-dimensional characterization of first instar horse and rhinoceros stomach bot fly larvae (Oestridae: Gasterophilinae: Gasterophilus, Gyrostigma): novel morphology and evolutionary implications

Larval characters are of importance in systematic and evolutionary studies of Diptera but lag behind characters of adults due to difficulties in obtaining relevant information. Larvae of stomach bot flies are obligate parasites completing development exclusively in the alimentary tract of equids and rhinoceroses. They possess diversified morphological adaptations, providing remarkable examples to further our understanding of larval evolution. Herein, three-dimensional structures of first instar Gasterophilus pecorum and Gyrostigma rhinocerontis are compared using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). We suggest CLSM has a large potential for exploiting cryptic character systems of micro fly larvae, as spectral range and intensity of autofluorescence emitted by sclerotized structures and soft tissues are distinct, presenting a high-contrast mechanism for multistructural visualization with non-destructive sample preparation. Five new potential synapomorphies are proposed to corroborate the sister-group Gasterophilus and Gyrostigma. The upward curving mouth-hooks of first instar Gasterophilus and Gyrostigma are distinctive in Cyclorrhapha and possibly serve to facilitate the larval subcutaneous migration within the host. Three types of mouthhooks are recognized in first instar Oestridae, with the gently curved and gradually tapered type optimized as the ancestral state, from which the gasterophiline and hypodermatine types evolved independently.

Deep Learning Methods On Neutron Scattering Data

Recently, by using deep learning methods, a computer is able to surpass or come close to matching human performance on image analysis and recognition. This advanced methods could also help extracting features from neutron scattering experimental data. Those data contain rich scientific information about structure and dynamics of materials under investigation. Deep learning could help researchers better understand the link between experimental data and materials properties. Moreover,it could also help to optimize neutron scattering experiment by predicting the best possible instrument configuration. Among all possible experimental methods, we begin our study on the small-angle neutron scattering (SANS) data and by predicting the structure geometry of the sample material at an early stage. This step is a keystone to predict the experimental parameters to properly setup the instrument as well as the best measurement strategy. In this paper, we propose to use transfer learning to retrain a convolutional neural networks (CNNs) based pre rained model to adapt the scattering images classification, which could predict the structure of the materials at an early stage in the SANS experiment. This deep neural network is trained and validated on simulated database, and tested on real scattering images.

Focusing and imaging of cold neutrons with a permanent magnetic lens

This paper reports imaging of objects with slow neutrons, specifically very cold neutrons and cold neutrons, at Institut Laue Langevin, using novel, permanent magnet (Nd₂Fe₁₄B) compound refractive lenses (MCRL) with a large 2.5 cm bore diameter. The MCRL focuses and images spin-up neutrons and defocuses spin-down neutrons via a large, radial magnetic field gradient. A single lens neutron microscope, composed of an MCRL objective lens with 2-fold magnification, was tested using very cold (slow) neutrons at 45 Å wavelength. One-to-one imaging was obtained using 16.7 Å polarized neutrons. The magnetic field gradient of the MCRL was measured by raster-scanned pencil beams on D33. Finally, a compound neutron microscope was realized using an MCRL condenser lens, which provided increased illumination of objects, and an MCRL as objective lens to produce 3.5-fold magnification.

Towards generalized data reduction on a chopper-based time-of-flight neutron reflectometer

The calculation of neutron reflectivity from raw time-of-flight data including instrumental corrections and an improved resolution calculation is presented. The theoretical calculations are compared with experimental data measured on the vertical sample plane reflectometer D17 and the horizontal sample plane reflectometer FIGARO at the Institut Laue–Langevin (ILL), Grenoble, France. This article comprises the mathematical body of the time-of-flight reflectivity data-reduction software COSMOS which is used on D17 and FIGARO.

Magnetic field-dependent spin structures of nanocrystalline holmium

The results are reported of magnetic field-dependent neutron diffraction experiments on polycrystalline inert-gas condensed holmium with a nanometre crystallite size (D = 33 nm). At T = 50 K, no evidence is found for the existence of helifan(3/2) or helifan(2) structures for the nanocrystalline sample, in contrast with results reported in the literature for the single crystal. Instead, when the applied field H is increased, the helix pattern transforms progressively, most likely into a fan structure. It is the component of H which acts on the basal-plane spins of a given nanocrystallite that drives the disappearance of the helix; for nanocrystalline Ho, this field is about 1.3 T, and it is related to a characteristic kink in the virgin magnetization curve. For a coarse-grained Ho sample, concomitant with the destruction of the helix phase, the emergence of an unusual angular anisotropy (streak pattern) and the appearance of novel spin structures are observed.

Muons as local probes of three-body correlations in the mixed state of type-II superconductors

The vortex glass state formed by magnetic flux lines in a type-II superconductor is shown to possess nontrivial three-body correlations. While such correlations are usually difficult to measure in glassy systems, the magnetic fields associated with the flux vortices allow us to probe these via muon-spin rotation measurements of the local field distribution. We show via numerical simulations and analytic calculations that these observations provide detailed microscopic insight into the local order of the vortex glass and more generally validate a theoretical framework for correlations in glassy systems.

Persistence length of titin from rabbit skeletal muscles measured with scattering and microrheology techniques

The persistence length of titin from rabbit skeletal muscles was measured using a combination of static and dynamic light scattering, and neutron small angle scattering. Values of persistence length in the range 9-16 nm were found for titin-II, which corresponds to mainly physiologically inelastic A-band part of the protein, and for a proteolytic fragment with 100-nm contour length from the physiologically elastic I-band part. The ratio of the hydrodynamic radius to the static radius of gyration indicates that the proteins obey Gaussian statistics typical of a flexible polymer in a -solvent. Furthermore, measurements of the flexibility as a function of temperature demonstrate that titin-II and the I-band titin fragment experience a similar denaturation process; unfolding begins at 318 K and proceeds in two stages: an initial gradual 50% change in persistence length is followed by a sharp unwinding transition at 338 K. Complementary microrheology (video particle tracking) measurements indicate that the viscoelasticity in dilute solution behaves according to the Flory/Fox model, providing a value of the radius of gyration for titin-II (63 +/- 1 nm) in agreement with static light scattering and small angle neutron scattering results.

Establishment of functional B cell memory against parvovirus B19 capsid proteins may be associated with resolution of persistent infection

Parvovirus B19 (B19) infection can occur during acute lymphoblastic leukemia and persistent viral infection can occur despite intravenous immunoglobulin administration. Here, evidence is presented that resolution of persistent B19 infection in an acute lymphoblastic leukemia patient may be associated with the simultaneous strengthening of antigen-specific B cell memory against the B19 capsid protein VP2 and diminution in the memory response against the B19 non-structural protein 1 (NS1). Determination of antigen-specific B cell memory status may enhance the serological and molecular analyses of persistent B19 infection.