Observation of WZγ Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter reports the observation of WZγ production and a measurement of its cross section using 140.1±1.2  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The WZγ production cross section, with both the W and Z bosons decaying leptonically, pp→WZγ→ℓ^{'}^{±}νℓ^{+}ℓ^{-}γ (ℓ^{(^{'})}=e, μ), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01±0.30(stat)±0.16(syst)  fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06  fb. The observed significance of the WZγ signal is 6.3σ, compared with an expected significance of 5.0σ.

Measurement and analysis of leakage neutron spectra from Lead slab samples with D-T neutrons

The leakage neutron spectra from three different sizes of Lead samples were measured by a TOF technique at 60° and 120°. The essential characteristic properties of the experimental measurement spectra can be reproduced well by MCNP code simulations with the ENDF/B-VIII.0, CENDL-3.2, JENDL-5.0, JEFF-3.3 and TENDL-2021 evaluated nuclear data libraries. The calculated results of JENDL-5.0 and JEFF-3.3 libraries agree better with the experimental data in the whole energy range. The results from ENDF/B-VIII.0 and CENDL-3.2 are overestimated in the 4-9 MeV range at 60° and in the 4-12.5 MeV range at 120°. The differences of the leakage neutron spectra by MCNP simulations using five evaluated nuclear data libraries mainly originate from the differences of the spectrum distributions of neutron reaction channels in these libraries. And the secondary neutron energy distribution and angular distribution from the five libraries have been present to explain it.

Direct Mass Measurements to Inform the Behavior of ^{128m}Sb in Nucleosynthetic Environments

Nuclear isomer effects are pivotal in understanding nuclear astrophysics, particularly in the rapid neutron-capture process where the population of metastable isomers can alter the radioactive decay paths of nuclei produced during astrophysical events. The β-decaying isomer ^{128m}Sb was identified as potentially impactful since the β-decay pathway along the A=128 isobar funnels into this state bypassing the ground state. We report the first direct mass measurements of the ^{128}Sb isomer and ground state using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. We find mass excesses of -84564.8(25)  keV and -84608.8(21)  keV, respectively, resulting in an excitation energy for the isomer of 43.9(33) keV. These results provide the first key nuclear data input for understanding the role of ^{128m}Sb in nucleosynthesis, and we show that it will influence the flow of the rapid neutron-capture process.

Combined Measurement of the Higgs Boson Mass from the H→γγ and H→ZZ^{*}→4ℓ Decay Channels with the ATLAS Detector Using sqrt[s]=7, 8, and 13 TeV pp Collision Data

A measurement of the mass of the Higgs boson combining the H→ZZ^{*}→4ℓ and H→γγ decay channels is presented. The result is based on 140  fb^{-1} of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11±0.09(stat)±0.06(syst)=125.11±0.11  GeV. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics.

Search for Dark Photons in Rare Z Boson Decays with the ATLAS Detector

A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139  fb^{-1} of sqrt[s]=13  TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}ϵ^{2}, in the dark photon mass range of [5, 40] GeV except for the ϒ mass window [8.8, 11.1] GeV. This search explores new parameter space not previously excluded by other experiments.

Clinical service evaluation of the feasibility and reproducibility of novel artificial intelligence based-echocardiographic quantification of global longitudinal strain and left ventricular ejection fraction in trastuzumab-treated patients

Introduction

Cardiotoxicity is a potential prognostically important complication of certain chemotherapeutic agents that may result in preclinical or overt clinical heart failure. In some cases, chemotherapy must be withheld when left ventricular (LV) systolic function becomes significantly impaired, to protect cardiac function at the expense of a change in the oncological treatment plan, leading to associated changes in oncological prognosis. Accordingly, patients receiving potentially cardiotoxic chemotherapy undergo routine surveillance before, during and following completion of therapy, usually with transthoracic echocardiography (TTE). Recent advancements in AI-based cardiac imaging reveal areas of promise but key challenges remain. There are ongoing questions as to whether the ability of AI to detect subtle changes in individual patients is at a level equivalent to manual analysis. This raises the question as to whether AI-based left ventricular strain analysis could provide a potential solution to left ventricular systolic function analysis in a manner equivocal to or superior to conventional assessment, in a real-world clinical service. AI based automated analyses may represent a potential solution for addressing the pressure of increasing echocardiographic demands within limited service-capacity healthcare systems, in addition to facilitating more accurate diagnoses.

Methods

This clinical service evaluation aims to establish whether AI-automated analysis compared to conventional methods (1) is a feasible method for assessing LV-GLS and LVEF, (2) yields moderate to good correlation between the two approaches, and (3) would lead to different clinical recommendations with serial surveillance in a real-world clinical population.

Results and Discussion

We observed a moderate correlation (r = 0.541) in GLS between AI automated assessment compared to conventional methods. The LVEF quantification between methods demonstrated a strong correlation (r = 0.895). AI-generated GLS and LVEF values compared reasonably well with conventional methods, demonstrating a similar temporal pattern throughout echocardiographic surveillance. The apical-three chamber view demonstrated the lowest correlation (r = 0.423) and revealed to be least successful for acquisition of GLS and LVEF. Compared to conventional methodology, AI-automated analysis has a significantly lower feasibility rate, demonstrating a success rate of 14% (GLS) and 51% (LVEF).

Association between chronic obstructive pulmonary disease and 28-day mortality in patients with sepsis: a retrospective study based on the MIMIC-III database

BACKGROUND

Sepsis is a common cause of mortality in critically ill patients, and chronic obstructive pulmonary disease (COPD) is one of the most common comorbidities in septic patients. However, the impact of COPD on patients with sepsis remained unclear. Therefore, the purpose of this study aimed to assess the effect of COPD on the prognosis of septic patients based on Medical Information Mart for Intensive Care (MIMIC-III) database.

METHODS

In this retrospective study based on the (MIMIC)-III database version 1.4 (v1.4), we collected clinical data and 28-day all-cause mortality from patients with sepsis in intensive care unit (ICU) and these patients met the diagnostic criteria of Sepsis 3 on ICU admission between 2008 and 2012. International Classification of Diseases (ICD-9) (4660, 490, 4910, 4911, 49120, 49121, 4918, 4919, 4920, 4928, 494, 4940, 4941, 496) was used to identified COPD. We applied Kaplan-Meier analysis to compare difference of 28-day all-cause mortality between septic patients with and without COPD. Cox proportional-hazards model was applied to explore the risk factor associated with 28-day all-cause mortality in patients with sepsis.

RESULTS

Six thousand two hundred fifty seven patients with sepsis were included in this study, including 955 (15.3%) patients with COPD and 5302 patients without COPD (84.7%). Compared with patients without COPD, patients with COPD were older (median: 73.5 [64.4, 82.0] vs 65.8 [52.9, 79.1], P < 0.001), had higher simplified acute physiology score II (SAPSII) (median: 40.0 [33.0, 49.0] vs 38.0 [29.0,47.0], P < 0.001) and greater proportion of mechanical ventilatory support (MV) (55.0% vs 48.9%, P = 0.001). In our study, septic patients with COPD had higher 28-day all-cause mortality (23.6% vs 16.4%, P < 0.001) than patients without COPD. After adjusting for covariates, the results showed that COPD was an independent risk factor for the 28-day all-cause mortality of patients with sepsis (HR 1.30, 95%CI: 1.12-1.50, P = 0.001).

CONCLUSIONS

COPD was an independent risk factor of 28-day all-cause mortality in septic patients. Clinically, septic patients with COPD should be given additional care.

Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector

This Letter reports the observation of single top quarks produced together with a photon, which directly probes the electroweak coupling of the top quark. The analysis uses 139  fb^{-1} of 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. Requiring a photon with transverse momentum larger than 20 GeV and within the detector acceptance, the fiducial cross section is measured to be 688±23(stat) _{-71}^{+75}(syst)  fb, to be compared with the standard model prediction of 515_{-42}^{+36}  fb at next-to-leading order in QCD.

Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02 TeV with the ATLAS Detector

This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02  TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72  nb^{-1} and 257  pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158 Collapse

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[Visual analysis of the current research status and hotspots of electric burns at home and abroad]

Objective: To analyze the literature on electric burns published at home and abroad, and to explore the research hotspots and frontiers of electric burns. Methods: The bibliometric method was used. The Chinese and English literature related to electric burns published in China National Knowledge Infrastructure, Wanfang database, VIP database and the core collection of Web of Science database from January 1, 2013 to December 31, 2022 were searched respectively, and the CiteSpace 6.2.R2 software was used for analysis. The number of papers, authors, countries, and institutions of Chinese and English literature were counted respectively, and the co-occurrence analysis of keywords and mutation analysis and cluster analysis on the basis of the co-occurrence analysis were conducted, besides, the clustering time line figure was obtained after the keywords were sorted by time to explore the current research status and the evolution process of hotspots in the field of electric burns. Results: A total of 398 English papers were retrieved from the core collection of Web of Science database, and a total of 523 Chinese papers were retrieved from China National Knowledge Infrastructure, Wanfang database, and VIP database after duplicate check. From 2013 to 2022, the number of English literature published in the field of electric burns showed a steadily upward trend, and the number of published Chinese literature showed a downward trend and tended to be stable. In Chinese literature, a total of 302 authors as the first author published papers related to electric burns, with 17 core authors published ≥3 papers; in English literature, a total of 320 authors as the first author published papers related to electric burns. Researches on electric burns were carried out in 65 countries, with United States having the most cooperation with other countries and the largest number of papers published. A total of 512 institutions at home and abroad published papers related to electric burns, and the institutions with the largest number of Chinese and English papers were Shanghai Electric Power Hospital in China (n=14) and Hallym University in Korea (n=11), respectively. A total of 1 176 Chinese keywords and 1 068 English keywords were included for co-occurrence analysis after excluding keywords related to the searching words. The top three keywords in frequency in Chinese literature were surgical flap, wound repair, and nursing, and the top three keywords in frequency in English literature were management, epidemiology, and children. Ten clusters were obtained by keyword analysis in Chinese literature, and the largest cluster was wound healing, followed by clinical effects and surgical flaps. Seven clusters were obtained by keyword analysis in English literature, and the largest cluster was reconstructive surgical procedures, followed by chronic pain and shock. The persistent clusters in Chinese literature were wound healing and clinical outcomes, etc., and the prominent nodes in the recent two years were surgical timing, limb electric burns, and hypertrophic scars; the persistent clusters in English literature were reconstructive surgical procedures and chronic pain, etc., and the prominent nodes in the recent two years were predictors and burn management, etc. In Chinese literature, the keyword with the longest duration of mutation (2017-2021) was wrist electric burns, and the keyword with the highest intensity of mutation was flap repair; in English literature, the keyword with the longest duration of the mutation (2019-2022) was voltage, and the keyword with the highest intensity of mutation was prevention. Conclusions: There are similarities and differences in the research directions and hotspots of electric burns at home and abroad. Surgical flap repair is a common research hotspot at home and abroad. At present, domestic research focuses on wound healing, wrist electric burns, and other aspects, while international research focuses on treatment management, epidemiology, reconstruction, and other aspects.

Measurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings

A key open question in the study of multiparticle production in high-energy pp collisions is the relationship between the "ridge"-i.e., the observed azimuthal correlations between particles in the underlying event that extend over all rapidities-and hard or semihard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To address this question, two-particle correlations are measured in pp collisions at sqrt[s]=13  TeV using data collected by the ATLAS experiment at the LHC, with an integrated luminosity of 15.8  pb^{-1}, in two different configurations. In the first case, charged particles associated with jets are excluded from the correlation analysis, while in the second case, correlations are measured between particles within jets and charged particles from the underlying event. Second-order flow coefficients, v_{2}, are presented as a function of event multiplicity and transverse momentum. These measurements show that excluding particles associated with jets does not affect the measured correlations. Moreover, particles associated with jets do not exhibit any significant azimuthal correlations with the underlying event, ruling out hard processes contributing to the ridge.

Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector

A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 140  fb^{-1} recorded by the ATLAS experiment at LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds are estimated based on a hybrid approach involving Monte Carlo simulations and data-driven methods. Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-J/ψ channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the J/ψ+ψ(2S) channel. The fitted masses and decay widths of the structures are reported.

Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector

This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44  nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057 Collapse

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Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10  TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60  TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

[Topography-guided transepithelial corneal collagen cross-linking by sequential ultraviolet A irradiation in different diameters for progressive keratoconus in adults]

Objective: To compare the efficacy and safety of a novel customized topography-guided transepithelial corneal collagen cross-linking (TG-CXL) procedure by sequential ultraviolet A irradiation in different diameters and conventional transepithelial corneal collagen cross-linking (TE-CXL) in adult patients with progressive keratoconus. Methods: A prospective cohort study was conducted. Adult patients diagnosed with progressive keratoconus in the Affiliated Xiamen Eye Center of Xiamen University were continuously recruited and randomly assigned to receive the TG-CXL or TE-CXL procedure from March 2020 to March 2021. Patients in the TE-CXL group were irradiated in the central 9-mm zone of the cornea (total energy, 7.2 J/cm2; irradiance, 45 mW/cm2), while patients in the TG-CXL group were first irradiated with the protocol used in the TE-CXL group, and further irradiated in the central 6-mm zone (total energy, 3.6 J/cm2; irradiance, 9 mW/cm2). The subjective symptom of pain and corneal fluorescein sodium staining were scored within postoperative 3 days. Slit lamp examination, measurements of uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), corneal topography, anterior segment optical coherence tomography, in vivo corneal confocal microscopy, corneal endothelial cell count, and non-contact tonometry were performed before surgery and at 3, 6, and 12 months after surgery. Results: A total of 66 patients were enrolled (mean age, 23.0±3.3 years old), with 33 patients (33 eyes) in each group. No statistically significant differences were found in age, gender, and maximum keratometry (Kmax) between the two groups (P>0.05). On day 1 after surgery, the average pain score of the TG-CXL group (2.21±0.45) was significantly higher than that of the TE-CXL group (1.32±0.33) (P<0.05). The pain was rapidly alleviated in both groups on days 2 and 3. On days 1 and 2, the corneal fluorescein sodium staining scores in the TG-CXL group (4.15±0.83 and 2.21±0.60, respectively) were significantly higher than those in the TE-CXL group (1.76±0.56 and 0.85±0.51, respectively, P<0.001), while there was no significant difference between the two groups at day3 (P=0.184). The UCVA and BCVA of the TG-CXL group at 3, 6, and 12 months after surgery were significantly improved when compared with the baseline. At 3, 6, and 12 months, the BCVA (LogMAR) of the TG-CXL group (0.21±0.15, 0.22±0.16, and 0.22±0.16, respectively) were significantly improved when compared with those of the TE-CXL group(0.32±0.15, 0.34±0.15, and 0.36±0.16, respectively, P<0.01). However, there was no significant difference in UCVA between groups at any time point after surgery (P>0.05). The spherical and cylindrical power values of the TG-CXL group were improved when compared with the baseline (P<0.05). However, no significant difference in spherical power values was found between the two groups at any time point after surgery (P>0.05). Meanwhile, there were significant differences in cylindrical power values between the two groups at 6 and 12 months after surgery (P<0.05). The Kmax in the TG-CXL group was improved at all of the time points after surgery when compared with the baseline (P<0.001), while no significant difference in Kmax was found at any time point after surgery in the TE-CXL group when compared with the baseline (P>0.05). At 6 and 12 months after surgery, the Kmax values in the TG-CXL group were significantly lower than the TE-CXL group (P<0.05). No significant differences were found in flat keratomety, steep keratometry, the minimal thickness of the cornea, endothelial cell density, and intraocular pressure between the two groups at any time point after surgery (P>0.05). Within one month after surgery, optical coherence tomography revealed the increased density in the anterior stroma in both groups. In most patients in the TG-CXL group, a demarcation line was visible in the central and para-central corneal stroma, representing a clear and continuous, high-signal arc-shaped linear structure, which was deeper in the central cornea than the para-central cornea. In contrast, a demarcation line, fuzzy and focally discontinuous, was visible only in a few patients in the TE-CXL group, with an almost uniform depth in the central and the para-central cornea. Confocal microscopy demonstrated an apparent mesh-like cross-linked collagen structure in the superficial and intermediate corneal stroma at all time points after surgery in the TG-CXL group, with thickening stromal collagen fibers and an increased number of interconnections. In contrast, the mesh-like structure and number of interconnections in the superficial corneal stroma were significantly reduced at 12 months after surgery in the TE-CXL group, with no cross-linking structure in the intermediate corneal stroma at any time point after surgery. No serious complications such as corneal infection, sterile corneal ulcer, and persistent epithelial defect were observed in both groups during the follow-up of 12 months. Conclusions: The TG-CXL procedure by sequential irradiation in two different diameters with ultraviolet A light was effective and safe in the management of progressive keratoconus in adults, achieving significant refractive improvement. This might be a good technical alternative for refractive corneal cross-linking surgery.

Dosimetric Advantages of Online Adaptative Radiotherapy for Cervical Cancer on 1.5T MR-Linac

PURPOSE/OBJECTIVE(S)

Online adaptative radiotherapy (ART) strategy can be applied to account for inter-fraction organ motion while limiting organ at risk (OAR) dose. This study aims to evaluate tumor target and OARs inter- and intrafraction motion using online MRI during the full course of MR-Linac radiotherapy fractions. Furthermore, quantify the dosimetric consequences of online adaptative compared with non-adaptative radiotherapy (non-ART) in cervical cancer.

MATERIALS/METHODS

Six cervix cancer patients were treated with 150 fractions on the 1.5 T Unity MR-Linac. Each fraction, pre-treatment MRI scans were obtained at the start of every treatment session, and post-treatment MRI scans were obtained at the end of every treatment session. A total 300 MR images were included in this study and the CTV, bladder and rectum were delineated on each MRI by the same radiation oncologist. The inter-fraction and intrafraction changes of contours were evaluated by dice similarity coefficient (DSC), Hausdorff distance (HD), volume difference (ΔV). The reference treatment plans were generated using step-and-shoot IMRT and utilized 9 beam groups on original CT. Then, the online adaptative treatment plans were obtained by re-optimizing based on the contours on daily pre-treatment MRI by "adapt to shape" workflow using the same beam parameters and optimization objectives from the reference plans. Non-ART plans for each patient were generated by recalculating the dose from the reference plans on daily online MRI by "adapt to position" workflow. CTV coverage and OARs constraints were used to compare ART and non-ART plans.

RESULTS

The results showed that large inter-fraction anatomical changes limited the efficacy of radiation therapy (CTV: DSC: 0.89±0.03, HD: 20.83±5.05mm, ΔV: 1.21%±5.44%; Bladder: DSC: 0.68±0.18, HD: 30.58±15.75mm, ΔV: -10.17%±61.19%; Rectum: DSC: 0.69±0.09, HD: 22.98±12.03mm, ΔV: 21.01%±20.59%).The intrafraction anatomical changes were smaller (CTV: DSC: 0.96±0.01, HD: 8.85±3.54mm, ΔV: -0.64%±1.90%; Bladder: DSC: 0.90±0.07, HD: 14.62±9.56mm, ΔV: 19.83%±21.71%; Rectum: DSC: 0.98±0.04, HD: 2.90±4.27mm, ΔV: 0.13%±5.04%) . Non-ART showed inadequate primary CTV coverage in 30% of the daily fractions. Online adaptative plans improved CTV coverage significantly (p<0.001) to 99%. Compared with non-ART, online ART decreased the fraction dose to bladder and rectum indicated by significant (p<0.001) improvements for daily D50%, D2% and Dmean.

CONCLUSION

In cervical cancer radiotherapy, a non-adaptive strategy led to inadequate target coverage for individual patients. Online adaptative radiotherapy corrected for day-to-day anatomical variations and resulted in adequate target coverage in all fractions. The dose to rectum and bladder was decreased significantly when applying online adaptative radiotherapy.

Hippocampal Sparing Whole Brain Radiation Therapy: 2 Arc Coplanar and 4 Arc Noncoplanar Planning Comparison

PURPOSE/OBJECTIVE(S)

Whole brain radiation therapy (WBRT) has been shown to provide palliation but with negative neurocognitive effects associated with radiation-induced damage to the hippocampus. Sparing of the hippocampus has been shown to reduce the risk of neurocognitive deficit. Hippocampal sparing WBRT plan optimization is commonly done using 2 arc coplanar technique. The purpose of this work is to show that 4 arc noncoplanar plans will improve hippocampal sparing without compromising PTV coverage.

MATERIALS/METHODS

Retrospective WBRT with hippocampal sparing using 2 arc coplanar and 4 arc noncoplanar VMAT technique were done on 10 patients previously treated for intracranial lesions. CT and MRI fused images were used to delineate the whole brain and hippocampus. Strictly following RTOG 0933 atlas guidelines, the hippocampus was manually delineated by a single Radiation Oncologist. Plans with prescription dose of 30 Gy in 10 fractions were generated using the 2 techniques. The 4 arc noncoplanar plan included 2 partial field arcs with couch angle at 90 degrees and 2 coplanar arcs. The 2 noncoplanar partial arcs consisted of a clockwise arc and a counterclockwise arc with gantry angles between 5 and 179 degrees. Lens were kept to < 7 Gy and pituitary gland to < 30 Gy. Dosimetric parameters from both techniques were compared by paired t-test.

RESULTS

Radiation dose to the hippocampus was significantly reduced using 4 arc noncoplanar plan when compared to 2 arc coplanar plan. While hippocampus D100% were similar (7.25 Gy vs 7.32 Gy, p = 0.557), the mean dose (9.46 Gy vs 9.87 Gy, p = 0.003) and D0.03cc (12.48 Gy vs 12.94 Gy, p < 0.001) were significantly reduced with 4 arc noncoplanar plans. Whole brain PTV coverage remained at V100% = 95% for both techniques. However, the 4 arc noncoplanar plans showed significantly improved D2% (32.56 Gy vs 32.97 Gy, P = 0.003), D98% (28.11 Gy vs 27.91 Gy, P = 0.01), and homogeneity index (0.141 vs 0.159, P < 0.001).

CONCLUSION

The 4 arc noncoplanar plans improved hippocampal sparing without compromising PTV coverage or compromise to other nearby organs at risk.

Radiation Therapy Sensitizes Head-and-Neck Cancer Cells to Killing by Chimeric Antigen Receptor (CAR)-NK Cells Targeting CD70

PURPOSE/OBJECTIVE(S)

CAR-T cell therapy is limited by toxicity, high cost, logistical manufacturing issues in the autologous setting and risk of GVHD in the allogeneic setting. Substitution of T cells with NK cells opens the possibility for an allogeneic off-the-shelf product with a better safety profile. However, the inadequate efficacy of CAR-NK cells against solid tumors can be extrapolated from experience with CAR-T cells. There is limited but promising preclinical evidence that radiation therapy (RT) enhances CAR-T cell tumoricidal activity against solid tumors. However, there is no data examining the potential synergy between RT and CAR-NK cell therapy.

MATERIALS/METHODS

We engineered CAR-NK cells with CD27 receptor as extracellular domain to target its natural ligand CD70, which is overexpressed in head-and-neck cancers (HNSCC). CAR-NK cell killing was assessed real-time through xCELLigence cytotoxicity assays. CD70+ OQ01 human HNSCCs were used for most experiments. FaDu is a CD70- HNSCC (negative ctrl). UMRC3 is a CD70+ kidney cancer cell line (positive ctrl). CD70 expression pre- and post-RT was assessed by flow cytometry and Western blot. Ionizing RT was compared at 5 doses: 0, 1.75, 3.5, 7, and 14 Gy. A single dose of 3.5 Gy was used for most experiments. Post-radiation effects were generally assessed at 3 days or 9 days post-RT. Intracellular staining was used to assess NK cell expression of IFN-γ, CD107a, and TNF-α by flow cytometry. CD27/CD70 interaction blockade was through α-CD27 pre-treatment of CAR-NK cells.

RESULTS

OQ01 HNSCCs heterogeneously express CD70 and are killed by CD70 CAR-NK cells in vitro. Pre-conditioning low-dose RT of 3.5 Gy applied to OQ01 HNSCCs 3 days prior to coculture with NK cells enhances CD70 CAR-NK cell killing, with ∼30% increased cytotoxicity against the tumor cells. Low-dose RT by itself did not induce acute cytolysis. As a possible mechanism for the increased sensitivity of irradiated OQ01 cells to CD70 CAR-NK cells, we found that RT enhances CD70 expression among HNSCCs in a dose-dependent manner. There was no increase in NK cell expression of IFN-γ, CD107a, and TNF-α with exposure to irradiated target cells. CD27/CD70 blockade does not solely abrogate RT-induced sensitization toward CAR-NK cell killing. Despite RT induction of transient increased expression of CD70, which normalizes by 9 days post-RT, there is persistent increase in RT-synergized target cell killing even at this later timepoint. Thus, altogether, RT sensitizes CD70-expressing HNSCC cells to CAR-NK cell killing in vitro.

CONCLUSION

This work represents the first preclinical study to identify the synergy of RT and CAR-NK cell therapy in solid tumors and is the first demonstration of CAR-NK cell activity against human HNSCCs. We show significantly enhanced potency of CAR-NK cells against irradiated tumor cells in vitro. Collectively, this research will be vital to guide efforts expanding into other target antigens and tumor types.

Effect of Anemia on Tumor Response to Preoperative Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

PURPOSE/OBJECTIVE(S)

Preoperative neoadjuvant chemoradiotherapy (nCRT) and total rectal mesenteric resection (TME) are the primary treatment options for locally advanced rectal cancer (LARC), but their efficacy varies. This study aimed to investigate the impact of anemia on the tumor response of patients with LARC receiving preoperative neoadjuvant chemoradiotherapy.

MATERIALS/METHODS

This study was a retrospective analysis of clinical and pathological data from patients with LARC who underwent nCRT and TME from January 2019 to May 2022 at a single institution. The tumor response was evaluated based on the tumor regression grade (TRG) and T-stage change of the primary tumor. Hemoglobin concentration was measured and graded to determine the presence of anemia. Anemia was categorized into four groups based on the hemoglobin levels: mild anemia (90-120 g/L), moderate anemia (60-90 g/L), severe anemia (30-60 g/L), and extreme anemia (less than 30 g/L). Finally, tumor response was quantified histologically using the AJCC 8th edition tumor regression grading system for rectal cancer and pre- and post-treatment T-grading.

RESULTS

A total of 88 patients with LARC who received nCRT and TME were included in the study, with 17 females and 71 males. Of these patients, 9 were moderately anemic and 37 were mildly anemic. The radiation therapy regimen was administered at a dose of 1.8-2 Gy per fraction, five times a week, for a total dose of 45-50.4 Gy. Capecitabine chemotherapy was also administered orally (825 mg/m2, twice a day) on the days of radiation therapy. Other chemotherapy regimens included XELOX and mFOLFOX6. The TRG was significantly different in anemic patients compared to non-anemic patients (P = 0.039). Only 2 out of 46 anemic patients (4%) showed an excellent response (TRG0), while 8 out of 42 non-anemic patients (19%) showed an excellent response (p = 0.043). There was also a significant difference in the incidence of anemia between cT3 and cT4 stages (p = 0.048), with 44% of cT3 patients and 67% of cT4 patients being anemic. The number of patients with poor response (TRG2-3) decreased as the degree of anemia decreased, but no significant difference was found. The incidence of TRG3 was 11% in patients with moderate anemia and 7% in non-anemic patients (P = 0.863). There was no significant difference in postoperative pathological T-stage between anemic and non-anemic patients. 89% of anemic patients had a pathological stage of ypT3 or less after chemoradiotherapy, while 95% of non-anemic patients did (P = 0.167). The pre- and post-treatment pathological staging did not significantly differ between anemic and non-anemic patients. 67% of anemic patients had descending tumors, while 59.5% of non-anemic patients had descending tumors (p = 0.509).

CONCLUSION

Patients with LARC who have normal hemoglobin concentrations during nCRT have better tumor regression compared to patients with anemia. Additionally, the incidence of anemia was higher among patients with advanced T-stage prior to treatment.

Inter-fractional Assessment during MR-guided Online Adaptive Radiotherapy for Glioblastoma

PURPOSE/OBJECTIVE(S)

Magnetic resonance image (MRI) guided radiation therapy has the potential to improve outcomes for glioblastoma by adapting to tumor changes during radiation therapy. This study aimed to assess the feasibility and potential benefits of MR-guided online adaptive radiotherapy (MRgOART) for patients with glioblastoma.

MATERIALS/METHODS

Twenty consecutive patients with glioblastoma were treated with MRgOART of 60 Gy in 30 fractions by the 1.5 T MR-Linac. The MRgOART fractions employed daily MR scans and the contours were utilized to create each adapted plan. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated on MRI of pre-treatment simulation (Fx0) and all fractions (Fx1, Fx2, Fx3 ... Fx30) to evaluate the inter-fractional changes. These changes were quantified using absolute/relative volume (∆V), Dice similarity coefficient (DSC) and Hausdorff distance (HD) metrics. The reference treatment plans were generated using step-and-shoot IMRT and utilized 7-9 beam groups on original CT. Before the treatment, a synthetic CT (sCT) quality assurance (QA) process was performed to assess the dose accuracy of bulk relative electron density (rED) assignment for online MRI based treatment plan in terms of gamma analysis, point dose comparison and dose volume histogram (DVH) parameters. Then, the online adaptative treatment plans were obtained by re-optimizing based on the contours on daily pre-treatment MRI by "adapt to shape" workflow. Non-adaptive plans for each patient were generated by recalculating the dose from the reference plans on daily online MRI by "adapt to position" workflow. GTV and CTV coverage and organ at risk (OAR) constraints were used to compare non-adaptive and adaptive plans.

RESULTS

For both criteria, the 1%/1mm (98.58%±0.15%) and 2%/2mm (99.88%±0.18%) gamma passing rate results were always clinically acceptable in sCT QA process. The differences on point dose and DVH parameters between the plans based on sCT and original CT were less than 1%. A total of 20 patients with 600 fractions were evaluated. The results showed that large inter-fractional changes for GTV limited the efficacy of radiation therapy (DSC: 0.78±0.08, HD: 20.94±3.64mm, ∆V: 2.92%±6.36%). The inter-fractional CTV changes were smaller (DSC: 0.91±0.04, HD: 15.31±3.09mm, ∆V: 1.41%±1.29%). GTV coverage of non-adaptive plans was below the prescribed coverage in 228/600 fractions (38%), with 90 (15%) failing by more than 10%. For CTV coverage of non-adaptive plans, the changes were less than 5%. Online adaptative plans improved GTV and CTV coverage significantly (p<0.001) to 99%. The adaptive plans also had lower dose to whole brain than non-adaptive plans (p<0.001).

CONCLUSION

Significant inter-fractional tumor changes could be found during radiotherapy in patients with glioblastoma treated by the 1.5 T MR-Linac. Daily MR-guided re-optimization of treatment plans corrected for day-to-day anatomical variations and resulted in adequate target coverage in all fractions.

Adaptive Auto-Segmentation for MRI-Guided Online Adaptive Radiotherapy of Cervical Carcinoma

PURPOSE/OBJECTIVE(S)

Accurate and efficient delineation of organs and targets on session images is critical in MRI-guided online adaptive radiotherapy (MRgOART). This study proposes a registration-guided deep learning image segmentation framework to assist online delineation of cervical carcinoma.

MATERIALS/METHODS

A total of 300 T2-weighted MR images were acquired for patients with cervical carcinoma treated by a 1.5T Unity MR-Linac. The CTV, bladder, rectum, pelvic bone and femoral joints were delineated on each MRI by the same radiation oncologist. To overcome these obstacles to online MRI segmentation, we propose a registration-guided DL (RgDL) segmentation framework that integrates image registration algorithms and DL segmentation models. Firstly, the DL segmentation model was trained using nnU-net. Then, for each treatment fraction, the deformable image registration (DIR) algorithm generates initial contours from previous treatment fraction, which were used as guidance by DL model to obtain the accurate current segmentation. The segmentation accuracy of alone DIR, DL and RgDL were evaluated by dice similarity coefficients (DSC) and other distance-based metrics.

RESULTS

Compared to the baseline approaches using the DIR and the DL alone, RgDL achieved a DSC of 91.12% on CTV, higher than DIR and DL alone by 15.54% and 10.13%. The DSC of RgDL were improved to 95.58%, 93.65%, 87.8% and 94.84% for bladder, pelvic bone, rectum and femoral joints, higher than DIR and DL alone by 9.61% on average.

CONCLUSION

The proposed adaptive auto-segmentation method can achieve accurate and efficient segmentation and potentially overcome these obstacles to MRgOART.

Influence of Eyes Movement on Lens Dose during MR-Guided Radiotherapy for Brain Tumor

PURPOSE/OBJECTIVE(S)

Modern radiotherapy techniques achieve highly conformal target doses while avoiding organs at risk such as lens. The magnitude of eyes movement and its influence on lens dose is unclear. The lens dose is relevant for cataract formation. This study aims to evaluate the movement-range of lens and its influence on dose distribution during MR-guided radiotherapy for brain cancer patients.

MATERIALS/METHODS

Fifty patients with brain cancer who were treated with MR-guided radiotherapy on 1.5 T MR-Linac were included in this study. All patients underwent a pre-treatment MRI and post-treatment MRI for each fraction. The eyes and lens were delineated on each MR image by a radiation oncologist. The reference treatment plans based original CT were recalculated on each MRI by "adapt to position" workflow. Then, we created planning risk volume (PRV) for lens by adding population margin and reoptimized the reference plans to evaluate the dose changes for lens. Inter-fraction and intrafraction variability for eyes and lens were evaluated with the Dice similarity coefficient (DSC), the Hausdorff distance (HD) and mean distance to agreement (MDA). Differences in daily dose (Dmax and Dmean) for eyes and lens were assessed.

RESULTS

A total of 300 MR images were analyzed in this study. The eyes motion was observed (minimum DSC: 0.57; maximum HD: 10.53; maximum MDA: 3.13). And the obvious lens motion also was found (minimum DSC: 0.01; maximum HD: 10.78; maximum MDA: 5.68). The maximum dose changes for eyes were up to 34.1% and the mean dose changes were up to 18.1%. The maximum dose changes for lens were up to 97.9% and the mean dose changes for eyes were up to 89%. When the reoptimized plans were generated by PRV lens, the dose changes were decreased nearly to 0.

CONCLUSION

Eyes movements in all radiotherapy fractions result in higher lens doses and potentially increase cataract formation rate. Adding margin expansions in treatment planning, to account for eyes motion, is the feasible approach to limit lens dose.

Megf10-related engulfment of excitatory postsynapses by astrocytes following severe brain injury

AIMS

To investigate astrocyte-related phagocytosis of synapses in the ipsilateral hippocampus after traumatic brain injury (TBI).

METHODS

We performed controlled cortical impact to simulate TBI in mice. Seven days postinjury, we performed cognitive tests, synapse quantification, and examination of astrocytic phagocytosis in association with Megf10 expression.

RESULTS

During the subacute stage post-TBI, we found a reduction in excitatory postsynaptic materials in the ipsilateral hippocampus, which was consistent with poor performance in the cognitive test. The transcriptome data suggested that robust phagocytosis was responsible for this process. Coincidently, we identified phagocytic astrocytes containing secondary lysosomes that were wrapped around the synapses in the ipsilateral hippocampus. Moreover, a significant increase in the co-location of GFAP and PSD-95 in the CA1 region suggested astrocytic engulfment of excitatory postsynaptic proteins. After examining the reported phagocytic pathways, we found that both the transcription level and protein expression of Megf10 were elevated. Co-immunofluorescence of GFAP and Megf10 demonstrated that the expression of Megf10 was spatially upregulated in astrocytes, exclusively in the CA1 region, and was related to the astrocytic engulfment of PSD-95.

CONCLUSION

Our study elaborated that the Megf10-related astrocytic engulfment of PSD-95 in the CA1 region of the ipsilateral hippocampus aggravated cognitive dysfunction following severe TBI.

Pilot Study of a Novel Ring Gantry-Based PET/CT Linear Accelerator in Patients with Prostate Cancer Receiving [18F]-DCFPyL for PSMA PET Imaging

PURPOSE/OBJECTIVE(S)

The RefleXion X1® system is a hybrid PET imaging-radiotherapy system that uses real-time positron emissions from a PET tracer to deliver biologically guided radiotherapy (BgRT). This study (NCT05470699) evaluated the hypothesis that the X1 PET imaging subsystem would be able to detect [18F]-DCFPyL PSMA PET signal sufficient to generate a deliverable BgRT plan in patients with prostate cancer.

MATERIALS/METHODS

Patients with prostate cancer scheduled for a diagnostic [18F]-DCFPyL PSMA PET scan as part of standard of care were eligible. Upon completion of the diagnostic PSMA PET scan, images were transferred to the radiotherapy planning system for target identification and contouring. If at least one PET avid tumor lesion was identified, the patient was then scanned on the X1 unit. BgRT planning was performed on each X1 scanned patient. The target lesion volume, activity concentration (AC) and normalized target signal (NTS) were acquired. Successful and deliverable BgRT plans required that the target AC was ≥ 5 kBq/ml and NTS ≥ 2.7.

RESULTS

Twenty-six patients underwent [18F]-DCFPyL PET scans (13 with rising PSA after surgery or radiotherapy, 6 with known metastases and 7 with newly diagnosed high-risk prostate cancer). Median (range) PSA was 3.40 (0.04-122). In 16 patients a PET avid tumor was identified and contoured for planning (4 lymph nodes, 5 bone, 6 prostate gland, and 1 prostate bed). In 13 patients the target lesion was visualized on the X1 PET scan, while in 3 patients the target lesion was too close to the bladder to be clearly visualized. BgRT planning was feasible and met standard of care published SBRT organ dose constraints in 8 patients (3 prostate gland, 3 bone, 2 lymph nodes). BgRT planning was not feasible in 8 patients due to insufficient AC, low NTS or proximity of the target lesion to the PET avid bladder. The accompanying table compares median (range) target volume, AC and NTS for feasible versus not feasible plans.

CONCLUSION

This is the first study to investigate the feasibility of using [18F]-DCFPyL PET imaging for BgRT plan generation on the X1 system in patients with prostate cancer. Lesions that are relevant to radiotherapy of prostate cancer can be visualized including lymph node and bone metastases. A dedicated BgRT workflow with PSMA PET imaging on the X1 at 60 minutes post injection will result in higher target AC and will optimize BgRT planning. PET avid lesions < 1 cm or close to the bladder may make BgRT planning challenging. [18F]-DCFPyL-guided BgRT is technically feasible using the RefleXion X1. BgRT using targeted PET radiopharmaceuticals to biologically guide external beam radiotherapy represents a promising new dimension in radiation oncology and warrants further investigation.