Search

Surgical navigation-assisted interventions, providing augmented previously acquired image data to support the physician, are routinely used. Visualization techniques like extended reality (XR) promise improvements because the desired information can be shown where most suitable. The accuracy of such systems is essential for usability in clinical interventions but lacks research. This work shows a system to project thermal data for use in reconstructive surgery and investigates the accuracy of the XR technology. The system consists of a thermal camera (PI450, Optris GmbH, Germany), a depth camera system (D415, Intel Inc., USA), and a HoloLens2 (Microsoft Corp., USA). 5 probands annotated the locations of 9 marker points on a calibration pattern of the real object and the projection in the XR headset. The mean and max residual projection errors were 2.8 and 6.2 mm, respectively. An XR system to superimpose thermal images was shown. The mean projection error of 2.8 mm is sufficient for further exploration of medical applications.

Intraoperative near-infrared fluorescence angiography with indocyanine green (ICG-FA) is a well-established modality in gastrointestinal surgery. Its main drawback is the application of a fluorescent agent with possible side effects for patients. The goal of this review paper is the presentation of alternative, non-invasive optical imaging methods and their comparison with ICG-FA.The principles of ICG-FA, spectral imaging, imaging photoplethysmography (iPPG), and their applications in gastrointestinal surgery are described based on selected published works.The main applications of the three modalities are the evaluation of tissue perfusion, the identification of risk structures, and tissue segmentation or classification. While the ICG-FA images are mainly evaluated visually, leading to subjective interpretations, quantitative physiological parameters and tissue segmentation are provided in spectral imaging and iPPG. The combination of ICG-FA and spectral imaging is a promising method.Non-invasive spectral imaging and iPPG have shown promising results in gastrointestinal surgery. They can overcome the main drawbacks of ICG-FA, i.e. the use of contrast agents, the lack of quantitative analysis, repeatability, and a difficult standardization of the acquisition. Further technical improvements and clinical evaluations are necessary to establish them in daily clinical routine.

This newsletter highlights two interesting new projects recently started within ACBN: One of them is based on a highly prestigious START grant, the first one to be acquired by ACBN members! Another story features our activities within the European Researchers’ Night. Not all of you may know this yet: It is a Europe-wide public event organized by the EU that displays both ongoing research and its impact on citizen’s life. The golden rule of communication: Tua res agitur (it is matter that concerns you). Horaz was up to date. In this edition you will find: FWF board decided to fund the ESPRIT fellowship application submitted by Giorgia Nasi Functional Studies on Extra-lysosomal Legumain: START Project # Y01469 by Elfriede Dall The Molecular Immunology Lab

Recent results obtained from leading cosmic ray experiments indicate that simulations using LHC-tuned hadronic interaction models underestimate the number of muons in extensive air showers compared to experimental data. This is the so-called muon deficit problem. Determination of the muon component in the air shower is crucial for inferring the mass of the primary particle, which is a key ingredient in the efforts to pinpoint the sources of ultra-high energy cosmic rays.In this paper, we present a new method to derive the muon signal in detectors, which uses the difference between the total reconstructed (data) and simulated signals is roughly independent of the zenith angle, but depends on the mass of the primary cosmic ray. Such a method offers an opportunity not only to test/calibrate the hadronic interaction models, but also to derive the $\beta$ exponent, which describes an increase of the number of muons in a shower as a function of the energy and mass of the primary cosmic ray. Detailed simulations show a dependence of the $\beta$ exponent on hadronic interaction properties, thus the determination of this parameter is important for understanding the muon deficit problem. We validate the method by using Monte Carlo simulations for the EPOS-LHC and QGSJetII-04 hadronic interaction models, and showing that this method allows us to recover the ratio of the muon signal between EPOS-LHC and QGSJetII-04 and the average $\beta$ exponent for the studied system, within less than a few percent. This is a consequence of the good recovery of the muon signal for each primary included in the analysis., Comment: This work corresponds to the presentation at the ICNFP 2022 at Kolymbari, Crete, in September 2022. The proceedings will be published in Physica Scripta. arXiv admin note: text overlap with arXiv:2108.07527

Image-guided high-intensity focused ultrasound (HIFU) has been increasingly used in medicine over the past few decades, and several systems for such have become commercially available. HIFU has passed regulatory approval around the world for the ablation of various solid tumors, the treatment of neurologic diseases, and the palliative management of bone metastases. The mechanical and thermal effects of focused ultrasound provide a possibility for histotripsy, supportive radiation therapy, and targeted drug delivery. The integration of imaging modalities into HIFU systems allows for precise temperature monitoring and accurate treatment planning, increasing the safety and efficiency of treatment. Preclinical and clinical results have demonstrated the potential of image-guided HIFU to reduce adverse effects and increase the quality of life postoperatively. Interventional nuclear image–guided HIFU is an attractive noninvasive option for the future.

High intensity focused ultrasound is used as a surgical tool to treat completely non-invasively several diseases. Examples of clinical applications are uterine fibroids, prostate cancer, thyroid nodules, and varicose veins. Precise targeting is key for improving the treatment outcome. A method for an automated, robot-assisted tracking system was developed and evaluated. A wireless ultrasound scanner was used to acquire images of the target, in this case, a blood vessel. The active contour approach by Chan and Vese was used to segment and track while moving the scanner along the target structure with a collaborative robotic arm. The performance was assessed using a custom made Agar phantom. The mean tracking error, which is defined as the remaining distance of the lesion to the images’ centre line, was 0.27 mm ± 0.18 mm.

High-energy cosmic rays are observed indirectly by detecting the extensive air showers initiated in Earth’s atmosphere. The interpretation of these observations relies on accurate models of air shower physics, which is a challenge and an opportunity to test QCD under extreme conditions. Air showers are hadronic cascades, which give rise to a muon component through hadron decays. The muon number is a key observable to infer the mass composition of cosmic rays. Air shower simulations with state-of-the-art QCD models show a significant muon deficit with respect to measurements; this is called the Muon Puzzle. By eliminating other possibilities, we conclude that the most plausible cause for the muon discrepancy is a deviation in the composition of secondary particles produced in high-energy hadronic interactions from current model predictions. The muon discrepancy starts at the TeV scale, which suggests that this deviation is observable at the Large Hadron Collider. An enhancement of strangeness production has been observed at the LHC in high-density events, which can potentially explain the puzzle, but the impact of the effect on forward produced hadrons needs further study, in particular with future data from oxygen beam collisions., Astrophysics and space science;367(3)

The mass composition is one of the key observables to understand the nature and origin of ultra-high energy cosmic rays.The study of hadronic interactions at energies well beyond human-made accelerators is a fundamental probe of elementary particle physics. In previous analyses, the properties of the hadronic interactions were estimated under the assumption of a certain mass composition, typically proton-dominated, and the cross sections were calculated by fitting the tail of the $X_{max}$ distribution. In such an analysis, the impact of a possible He-contamination on the cross section measurement is quoted as a systematic uncertainty. Vice versa, the cosmic-ray mass composition is typically determined using air shower simulations by assuming the validity of the considered hadronic interaction models. In this contribution, we present a fully self-consistent approach of varying the proton-proton cross sections, with the nucleus-nucleus cross sections being predicted via the Glauber theory, and making a full $X_{max}$ distribution fit to get an independent and simultaneous estimation of the interaction cross sections and cosmic-ray primary composition. We will discuss the degeneracy between mass composition and hadronic interactions and compare the sensitivity of the proposed method to one of the previous approaches.

We explore the possibility of a common origin of ultrahigh energy cosmic rays (UHECRs) and astrophysical neutrinos and further constrain sources which are consistent with this possibility. We show that the common origin hypothesis can be satisfied for the Sibyll2.3c hadronic interaction model but is difficult to accommodate for EPOS-LHC, showing that multimessenger analyses have the power to also constrain hadronic physics beyond LHC energies. We constrain properties of UHECR source environments (and potentially astrophysical neutrino sources), including their photon temperature, gas density, size, magnetic field strength and coherence length, using UHECR and neutrino spectra and composition. Our analysis represents a new type of information on UHECR sources, independent of the mechanism responsible for the UHECR acceleration.

Complex morphological traits are the product of many genes with transient or lasting developmental effects that interact in anatomical context. Mouse models are a key resource for disentangling such effects, because they offer myriad tools for manipulating the genome in a controlled environment. Unfortunately, phenotypic data are often obtained using laboratory-specific protocols, resulting in self-contained datasets that are difficult to relate to one another for larger scale analyses. To enable meta-analyses of morphological variation, particularly in the craniofacial complex and brain, we created MusMorph, a database of standardized mouse morphology data spanning numerous genotypes and developmental stages, including E10.5, E11.5, E14.5, E15.5, E18.5, and adulthood. To standardize data collection, we implemented an atlas-based phenotyping pipeline that combines techniques from image registration, deep learning, and morphometrics. Alongside stage-specific atlases, we provide aligned micro-computed tomography images, dense anatomical landmarks, and segmentations (if available) for each specimen (N=10,056). Our workflow is open-source to encourage transparency and reproducible data collection. The MusMorph data and scripts are available on FaceBase (www.facebase.org, doi.org/10.25550/3-HXMC) and GitHub (https://github.com/jaydevine/MusMorph).

Astrophysical candidates for the sources of ultra-high-energy cosmic rays (UHECRs) exhibit a large diversity in terms of their properties relevant for the acceleration of charged particles, such as luminosity, Lorentz factor, size and magnetic field. Yet, fits of the observed UHECR spectrum and composition often assume identical sources. Here we investigate a population of sources with a power-law distribution of maximum energies. We show that the allowed source-to-source variance of the maximum energy must be small to describe the UHECR data. Even in the most extreme scenario, with a very sharp cutoff of individual source spectra and negative redshift evolution of the accelerators, the maximum energies of 90% of sources must be identical within a factor of three – in contrast to the variance expected for astrophysical sources. However, the overall population variance can be large when maximum rigidities are distributed as a broken power law, with a steep decline above the break and with hard source spectra. In this scenario, most of the observed UHECR flux is produced by sources near the break.

We explore inferences on ultrahigh energy cosmic ray (UHECR) source environments -- constrained by the spectrum and composition of UHECRs and non-observation of extremely high energy neutrinos -- and their implications for the observed high energy astrophysical neutrino spectrum. We find acceleration mechanisms producing power-law CR spectra~$\propto E^{-2}$ are compatible with UHECR data, if CRs at high rigidities are in the quasi-ballistic diffusion regime as they escape their source environment. Both gas-dominated and photon-dominated source environments are able to account for UHECR observations, however photon-dominated sources give a better fit. Additionally, gas-dominated sources are in tension with current neutrino constraints. Accurate measurement of the neutrino flux at $\sim 10$ PeV will provide crucial information on the viability of gas-dominated sources, as well as whether diffusive shock acceleration is consistent with UHECR observations. We also show that UHECR sources are able to give a good fit to the high energy portion of the astrophysical neutrino spectrum, above $\sim$ PeV. This common origin of UHECRs and high energy astrophysical neutrinos is natural if air shower data is interpreted with the Sibyll2.3c hadronic interaction model, which gives the best-fit to UHECRs and astrophysical neutrinos in the same part of parameter space, but not for EPOS-LHC.

The number of muons in extensive air showers predicted using LHC-tuned hadronic interaction models, such as EPOS-LHC and QGSJetII-04, is smaller than observed in showers recorded by leading cosmic ray experiments. In this paper, we present a new method to derive muon rescaling factors by analyzing reconstructions of simulated showers. The z-variable used (difference of initially simulated and reconstructed total signal in detectors) is connected to the muon signal and is roughly independent of the zenith angle but depends on the mass of primary cosmic ray. The performance of the method is tested using Monte Carlo shower simulations for the hybrid detector of the Pierre Auger Observatory. Having an individual z-value from each simulated hybrid event, the corresponding signal at 1000 m from the shower axis, and using a parametrization of the muon fraction in simulated showers, we can calculate the multiplicative rescaling parameters of the muon signals in the ground detector even for an individual event. We can also study its dependence as a function of zenith angle and the mass of primary cosmic ray. This gives a possibility not only to test/calibrate the hadronic interaction models, but also to derive the $\beta$-exponent, describing an increase of the number of muons as a function of primary energy and mass of the cosmic ray. Detailed simulations show dependence of the $\beta$-exponent on hadronic interaction properties, thus the determination of this parameter is important for understanding the muon deficit problem., Comment: Proceedings of 37th International Cosmic Ray Conference (ICRC 2021), July 12th -- 23rd, 2021