Gut feelings: the relations between depression, anxiety, psychotropic drugs and the gut microbiome

The gut microbiome is involved in the bi-directional relationship of the gut - brain axis. As most studies of this relationship are small and do not account for use of psychotropic drugs (PTDs), we explored the relations of the gut microbiome with several internalizing disorders, while adjusting for PTDs and other relevant medications, in 7,656 Lifelines participants from the Northern Netherlands (5,522 controls and 491 participants with at least one internalizing disorder). Disorders included dysthymia, major depressive disorder (MDD), any depressive disorder (AnyDep: dysthymia or MDD), generalized anxiety disorder (GAD) and any anxiety disorder (AnyAnx: GAD, social phobia and panic disorder). Compared to controls, 17 species were associated with depressive disorders and 3 were associated with anxiety disorders. Around 90% of these associations remained significant (FDR <0.05) after adjustment for PTD use, suggesting that the disorders, not PTD use, drove these associations. Negative associations were observed for the butyrate-producing bacteria Ruminococcus bromii in participants with AnyDep and for Bifidobacterium bifidum in AnyAnx participants, along with many others. Tryptophan and glutamate synthesis modules and the 3,4-Dihydroxyphenylacetic acid synthesis module (related to dopamine metabolism) were negatively associated with MDD and/or dysthymia. After additional adjustment for functional gastrointestinal disorders and irritable bowel syndrome, these relations remained either statistically (FDR <0.05) or nominally (P < 0.05) significant. Overall, multiple bacterial species and functional modules were associated with internalizing disorders, including gut - brain relevant components, while associations to PTD use were moderate. These findings suggest that internalizing disorders rather than PTDs are associated with gut microbiome differences relative to controls.

Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at sqrt[s_{NN}]=200 GeV

The polarization of Λ and Λ[over ¯] hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sqrt[s_{NN}]=200  GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p_{T} dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and p_{T} dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

Exploring the ignored role of escaped algae in a pilot-scale DWDS: Disinfectant consumption, DBP yield and risk formation

Insufficient treatments during bloom-forming seasons allow algae to enter the subsequent drinking water distribution system (DWDS). Yet, scarce information is available regarding the role escaped algae to play in the DWDS, and how they interact with the system. Thus, three scenarios were conducted: a pilot DWDS with algae (a), pipe water (b), and pipe water with algae (c). Experimental results showed that, compared to biofilm and bulk water, escaped algae required fewer disinfectants. Competition for disinfectants varied with algal strains (Microcystis aeruginosa, MA; Pseudanabaena sp., PS) and disinfectant types (chlorine, Cl2; chloriamine, NH2Cl). Algae in the MA-Cl2 group showed the highest demand (6.25%-36.02%). However, the low-concentration disinfectants distributed to algae could trigger distinct algal status alternations. Cl2 diffused into intact MA cells and reacted with intracellular compositions. Damaged PS cells reached 100% within 2 h. Typical disinfection byproducts (DBPs), including trihalomethanes (THMs), haloacetic acids and halogenated acetonitriles were examined. Disinfectant types and algal strains affected DBP yield and distribution. Although disinfectants consumed by algae might not promote dissolved DBP formation, especially for THMs. DBP formation of the other components was affected by escaped algae via changing disinfectant assignment (reduced by 45.45% for MA-Cl2) and transformation efficiency (by 34.52%). The cytotoxicity risks were estimated. Dissolved DBP-induced risks were not added when escaped algae occurred, whereas disruption and release of intracellular substances increased risks; the maximum cytotoxicity did not occur at 12 h rather than at the end (24 h). Overall, this study provided an innovative perspective on algal-related water quality issues in water systems.

Reentrance of interface superconductivity in a high-Tc cuprate heterostructure

Increasing the carrier density in a Mott insulator by chemical doping gives rise to a generic superconducting dome in high temperature superconductors. An intriguing question is whether a second superconducting dome may exist at higher dopings. Here we heavily overdope La2-xSrxCuO4 (0.45 ≤ x ≤ 1.0) and discover an unprecedented reentrance of interface superconductivity in La2-xSrxCuO4 /La2CuO4 heterostructures. As x increases, the superconductivity is weakened and completely fades away at x = 0.8; but it revives at higher doping and fully recovers at x = 1.0. This is shown to be correlated with the suppression of the interfacial charge transfer around x = 0.8 and the weak-to-strong localization crossover in the La2-xSrxCuO4 layer. We further construct a theoretical model to account for the sophisticated relation between charge localization and interfacial charge transfer. Our work advances both the search for and control of new superconducting heterostructures.

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.

Large-scale characterization of hospital wastewater system microbiomes and clinical isolates from infected patients: profiling of multi-drug-resistant microbial species

BACKGROUND

Hospital-acquired infections (HAIs) and infectious agents exhibiting antimicrobial resistance (AMR) are challenges globally. Environmental patient-facing wastewater apparatus including handwashing sinks, showers and toilets are increasingly identified as sources of infectious agents and AMR genes.

AIM

To provide large-scale metagenomics analysis of wastewater systems in a large teaching hospital in the Republic of Ireland experiencing multi-drug-resistant HAI outbreaks.

METHODS

Wastewater pipe sections (N=20) were removed immediately prior to refurbishment of a medical ward where HAIs had been endemic. These comprised toilet U-bends, and sink and shower drains. Following DNA extraction, each pipe section underwent metagenomic analysis.

FINDINGS

Diverse taxonomic and resistome profiles were observed, with members of phyla Proteobacteria and Actinobacteria dominating (38.23 ± 5.68% and 15.78 ± 3.53%, respectively). Genomes of five clinical isolates were analysed. These AMR bacterial isolates were from patients >48 h post-admission to the ward. Genomic analysis determined that the isolates bore a high number of antimicrobial resistance genes (ARGs).

CONCLUSION

Comparison of resistome profiles of isolates and wastewater metagenomes revealed high degrees of similarity, with many identical ARGs shared, suggesting probable acquisition post-admission. The highest numbers of ARGs observed were those encoding resistance to clinically significant and commonly used antibiotic classes. Average nucleotide identity analysis confirmed the presence of highly similar or identical genomes in clinical isolates and wastewater pipes. These unique large-scale analyses reinforce the need for regular cleaning and decontamination of patient-facing hospital wastewater pipes and effective infection control policies to prevent transmission of nosocomial infection and emergence of AMR within potential wastewater reservoirs.

Relativistic ultrafast electron diffraction at high repetition rates

The ability to resolve the dynamics of matter on its native temporal and spatial scales constitutes a key challenge and convergent theme across chemistry, biology, and materials science. The last couple of decades have witnessed ultrafast electron diffraction (UED) emerge as one of the forefront techniques with the sensitivity to resolve atomic motions. Increasingly sophisticated UED instruments are being developed that are aimed at increasing the beam brightness in order to observe structural signatures, but so far they have been limited to low average current beams. Here, we present the technical design and capabilities of the HiRES (High Repetition-rate Electron Scattering) instrument, which blends relativistic electrons and high repetition rates to achieve orders of magnitude improvement in average beam current compared to the existing state-of-the-art instruments. The setup utilizes a novel electron source to deliver femtosecond duration electron pulses at up to MHz repetition rates for UED experiments. Instrument response function of sub-500 fs is demonstrated with < 100 fs time resolution targeted in future. We provide example cases of diffraction measurements on solid-state and gas-phase samples, including both micro- and nanodiffraction (featuring 100 nm beam size) modes, which showcase the potential of the instrument for novel UED experiments.

Occlusal Force Maintains Alveolar Bone Homeostasis via Type H Angiogenesis

Physiologically, teeth and periodontal tissues are exposed to occlusal forces throughout their lifetime. Following occlusal unloading, unbalanced bone remodeling manifests as a net alveolar bone (AB) loss. This phenomenon is termed alveolar bone disuse osteoporosis (ABDO), the underlying mechanism of which remains unclear. Type H vessels, a novel capillary subtype tightly coupled with osteogenesis, reportedly have a role in skeletal remodeling; however, their role in ABDO is not well studied. In the present study, we aimed to explore the pathogenesis of and therapies for ABDO. The study revealed that type H endothelium highly positive for CD31 and endomucin was identified in the periodontal ligament (PDL) but rarely in the AB of the mice. In hypofunctional PDL, the density of type H vasculature and coupled osterix+ (OSX+) osteoprogenitors declined significantly. In addition, the angiogenic factor Slit guidance ligand 3 (SLIT3) was downregulated in the disused PDL, and periodontal injection of the recombinant SLIT3 protein partially ameliorated type H vessel dysfunction and AB loss in ABDO mice. With regard to the molecular mechanism, a mechanosensory signaling circuit, PIEZO1/Ca2+/HIF-1α/SLIT3, was validated by applying cyclic compression to 3-dimensional-cultured PDL cells using the Flexcell FX-5000 compression system. In summary, PDL plays a pivotal role in mechanotransduction by translating physical forces into the intracellular signaling axis PIEZO1/Ca2+/HIF-1α/SLIT3, which promotes type H angiogenesis and OSX+ cell-related osteogenensis, thereby contributing to AB homeostasis. Our findings advance the understanding of PDL in AB disorders. Further therapies targeting SLIT3 may provide new insights into preventing bone loss in ABDO.

MRI features for prediction of the intravenous chemotherapy effect in patients with retinoblastoma

AIM

To investigate the value of orbital magnetic resonance imaging (MRI) features in predicting the efficacy of intravenous chemotherapy (IVC) for patients with retinoblastoma (RB).

MATERIALS AND METHODS

The pretreatment clinical and MRI data of 100 eyes from 80 RB patients who underwent IVC were collected retrospectively. There were 59 eyes in the effective group and 41 eyes in the ineffective group, and the baseline data of the two groups were compared statistically. Three radiologists reviewed and evaluated each lesion independently based on 25 MRI features. The predictive values of the MRI features for IVC efficacy were assessed by multi-factor logistic regression analysis, and their odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Receiver operating characteristic curves (ROCs) with the area under the curve (AUC) were used to determine the predictive abilities. A predictive model was constructed by integrating all independent predictors visualised by the nomogram.

RESULTS

There were no statistically significant differences in sex or age between the effective and ineffective groups. The results of multivariate regression analysis showed that laterality, margin, and anterior eye segment enhancement were identified as independent factors that could predict IVC efficacy. The predictive model combining these three features was constructed, and it had an AUC of 0.732 (95% CI: 0.633, 0.831, p<0.01), a sensitivity of 71.2%, and a specificity of 70.7%.

CONCLUSION

The data demonstrate that the orbital MRI features can be used to predict IVC efficiency before RB patients are treated.

MRI-based radiomics analysis of bladder cancer: prediction of pathological grade and histological variant

AIM

To develop magnetic resonance imaging (MRI)-based radiomics models for the prediction of the pathological grade and histological variant of bladder cancer.

MATERIALS AND METHODS

A total of 227 patients who underwent bladder MRI and had histopathologically confirmed grades and variants were included retrospectively from January 2017 to March 2022. They were assigned to a training set (n=131) and a testing set (n=96) based on the MRI system. MRI-based radiomics features were extracted from manually segmented volumes of interest from high-b-value DWI images and ADC maps. The radiomics models were trained with all possible pipelines in the training set. One optimal model was selected using the fivefold cross-validation method and verified by the testing set according to the pathological results. Univariate and multivariate analyses were performed to identify the significant clinical and imaging factors for developing clinical-radiomics models.

RESULTS

The radiomics model for grade prediction had area under the curve (AUC) values of 0.784, 0.786, and 0.733 in the training, cross-validation, and testing sets, respectively. The radiomics model for variant prediction had AUC values of 0.748, 0.757, and 0.789 in the training, cross-validation, and testing sets, respectively. The performance of the clinical-radiomics model was significantly improved compared with the radiomics models alone for the total dataset (AUC for grade: 0.846 versus 0.756; AUC for variant: 0.810 versus 0.757, p<0.05).

CONCLUSION

MRI-based radiomics models could be used to predict the pathological grade and histological variants of bladder cancer with relatively good performance.

Observation of New Baryons in the Ξ_{b}^{-}π^{+}π^{-} and Ξ_{b}^{0}π^{+}π^{-} Systems

The first observation and study of two new baryonic structures in the final state Ξ_{b}^{0}π^{+}π^{-} and the confirmation of the Ξ_{b}(6100)^{-} state in the Ξ_{b}^{-}π^{+}π^{-} decay mode are reported using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9  fb^{-1}. In addition, the properties of the known Ξ_{b}^{*0}, Ξ_{b}^{'-} and Ξ_{b}^{*-} resonances are measured with improved precision. The new decay mode of the Ξ_{b}^{0} baryon to the Ξ_{c}^{+} π^{-} π^{+} π^{-} final state is observed and exploited for the first time in these measurements.

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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Precision Measurement of CP Violation in the Penguin-Mediated Decay B_{s}^{0}→ϕϕ

A flavor-tagged time-dependent angular analysis of the decay B_{s}^{0}→ϕϕ is performed using pp collision data collected by the LHCb experiment at the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6  fb^{-1}. The CP-violating phase and direct CP-violation parameter are measured to be ϕ_{s}^{ss[over ¯]s}=-0.042±0.075±0.009  rad and |λ|=1.004±0.030±0.009, respectively, assuming the same values for all polarization states of the ϕϕ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pp collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕ_{s}^{ss[over ¯]s}=-0.074±0.069  rad and |λ|=1.009±0.030. This is the most precise study of time-dependent CP violation in a penguin-dominated B meson decay. The results are consistent with CP symmetry and with the standard model predictions.

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.

Measurement of the Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} Differential Branching Fraction

The branching fraction of the rare decay Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} is measured for the first time, in the squared dimuon mass intervals q^{2}, excluding the J/ψ and ψ(2S) regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9  fb^{-1}. The result in the highest q^{2} interval, q^{2}>15.0  GeV^{2}/c^{4}, where theoretical predictions have the smallest model dependence, agrees with the predictions.

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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Preparation of three structurally similar stationary phases with different ionizable terminal groups and evaluation of their retention performances under multiple modes in high performance liquid chromatography

Three structurally similar silane reagents with different terminal groups were prepared and bonded to silica to obtain three structurally similar stationary phases (Sil-Ph-COOH, Sil-Phe and Sil-Ph-NH2). The prepared stationary phases were characterized through elemental analysis (EA) and Fourier Transform Infrared Spectroscopy (FT-IR). These three stationary phases provided acceptable retention repeatability (relative standard deviations between 0.08% and 0.13%) and high column efficiency (7.3 × 104 plates/m for uridine on Sil-Phe). The retention behavior of the three columns was investigated under different chromatographic conditions including different mobile phase ratio, salt concentration, pH etc. The retention mechanisms were explored by linear solvation energy relationships and Van't Hoff plots. Applications in separation under reversed phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC) and ion exchange chromatography (IEC) mode were investigated. The results showed that the retention capacity of the stationary phases with different terminal groups to the analytes is very different, especially for carboxylic acids, because the surface charges of amino groups and carboxyl groups under weakly acidic conditions produce different electrostatic effects with dissociated carboxylic acids. Finally, the Sil-Phe column was employed to detect ibuprofen extracted from pharmaceutical ibuprofen capsules and vitamins extracted from vitamin tablets.

[Application progress of implementation research on diabetes management]

Diabetes is one of the most important non-communicable chronic diseases. Although a large amount of clinical evidence on the effectiveness of diabetes prevention and treatment interventions has been established, the current quality of care and results are still insufficient. Implementation Research can bridge the gap between research and practice. Implementation Research on diabetes management can clarify what is effective and what is ineffective in management, and promote the transformation of complex, multi-component interventions into medical practice faster and more effectively. This paper reviews the main research contents and application of implementation research of diabetes management at home and abroad, aiming to provide reference for related research and promote the application of implementation research in diabetes management in China.

Influence of Contrast Materials on Dose Accuracy of MR-Linac in Patients with SBRT Liver Cancer

PURPOSE/OBJECTIVE(S)

Objective: Intravenous injection of contrast agent during CT scanning can improve the accuracy of target area contouring, however the contrast agent will cause dose bias due to the high relative electron density. This study aims to explore the influence of contrast agent on the accuracy of dose calculation of the planning system during SBRT based on MRI-Linac for liver cancer treatment.

MATERIALS/METHODS

Methods: In this study, 20 patients undergoing stereotactic body radiation therapy (SBRT) for liver cancer were selected, and their complete unenhanced CT, contrast-enhanced CT, and corresponding structures were imported into Monaco V.5.4. The target and organs at risk (OARs) in the unenhanced CT and contrast-enhanced CT were additionally contoured according to the target contouring guidelines and OARs were ranked. The average relative electron densities of OARs (lung, spinal cord, heart, rib, etc.) were calculated with Monaco TPS. The reference plan is based on unenhanced CT for plan calculation (plan1). To compare the dosimetry errors caused by the synthetic CT, the average relative electron density of all structures in unenhanced CT was forced and the plans were recalculated (plan2). To investigate dosimetric differences caused by the changes of relative electron density due to the contrast agent, the average relative electron density of all structures in contrast-enhanced CT was forced and the plans were recalculated(plan3). The dosimetric differences in groups A (plan 1 and plan2), B (plan 1 and plan3), and C (plan2 and plan3) were compared, respectively.

RESULTS

There were not significant difference between three groups in the affected lung, heart, liver, blood, all within 3%. However, differences were significantly different in the group B. The maximum deviation of spinal cord Dmax reached 4.78%. In addition, the deviation of the dose parameters in the target area was small, except that the maximum deviation of the CI value in group B was 3.23%.

CONCLUSION

For SBRT planning of liver cancer based on magnetic resonance accelerator, synthetic CT has little influence on the calculation of planned dose. The dose difference caused by contrast materials is also relatively small, although the deviation of the CI value of the target area exceeds 3%, which is also within the clinical acceptance range. However, the deviation of the maximum value of the spinal cord is relatively large, exceeding the clinically acceptable range. Therefore, when optimizing the SBRT plan for liver cancer, attention should be paid to important organs such as the spinal cord, and should be avoided as far as possible when setting the fields.

Pneumonitis After Concurrent Chemoradiation and Immune Checkpoint Inhibition in Patients with Locally Advanced Non-small Cell Lung Cancer

AIMS

Pneumonitis is a common and potentially deadly complication of combined chemoradiation and immune checkpoint inhibition (CRT-ICI) in patients with locally advanced non-small cell lung cancer (LA-NSCLC). In this study we sought to identify the risk factors for pneumonitis with CRT-ICI therapy in LA-NSCLC cases and determine its impact on survival.

MATERIALS AND METHODS

We conducted a retrospective chart review of 140 patients with LA-NSCLC who underwent curative-intent CRT-ICI with durvalumab between 2018 and 2021. Pneumonitis was diagnosed by a multidisciplinary team of clinical experts. We used multivariable cause-specific hazard models to identify risk factors associated with grade ≥2 pneumonitis. We constructed multivariable Cox proportional hazard models to investigate the impact of pneumonitis on all-cause mortality.

RESULTS

The median age of the cohort was 67 years; most patients were current or former smokers (86%). The cumulative incidence of grade ≥2 pneumonitis was 23%. Among survivors, 25/28 patients had persistent parenchymal scarring. In multivariable analyses, the mean lung dose (hazard ratio 1.14 per Gy, 95% confidence interval 1.03-1.25) and interstitial lung disease (hazard ratio 3.8, 95% confidence interval 1.3-11.0) increased the risk for pneumonitis. In adjusted models, grade ≥2 pneumonitis (hazard ratio 2.5, 95% confidence interval 1.0-6.2, P = 0.049) and high-grade (≥3) pneumonitis (hazard ratio 8.3, 95% confidence interval 3.0-23.0, P < 0.001) were associated with higher all-cause mortality.

CONCLUSIONS

Risk factors for pneumonitis in LA-NSCLC patients undergoing CRT-ICI include the mean radiation dose to the lung and pre-treatment interstitial lung disease. Although most cases are not fatal, pneumonitis in this setting is associated with markedly increased mortality.

Simulation-Omitted Replan with Cone Beam Computed Tomography based Adaptive Online Radiotherapy System - Transferring Adapted Plan to Non-Adaptive Ring Gantry Linear Accelerator for Image Guided Radiotherapy

PURPOSE/OBJECTIVE(S)

Artificial intelligence powered cone beam computed tomography (CBCT) based online adaptive radiotherapy (oART) system offers a streamlined and efficient process for daily ART as the default. In our prior work, we developed a workflow to utilize this oART system as simulation-omitted replan platform and treat the adapted plan on the oART system with image guided radiotherapy (IGRT) until next adaptation. However, the IGRT fractions will occupy the treatment slots of the machine. In this work, we aim to develop a semi-automatic workflow to allow the adapted plan to be treat on the non-adaptive ring gantry linear accelerator (non-ART Linac) and dedicate the oART system for adaptive treatments.

MATERIALS/METHODS

The oART system and the non-ART Linac were machine-matched to the same representative beam data. In the oART system, the initial plan is setup as 'adaptive' treatment and patients are only treated on the oART system for adaptive replan. The IGRT fractions are all treated on the non-ART Linac. An API script was developed to automatically (1) grab the adapted DICOM plan files from the secondary calculation system and write directly back to the database of the treatment management system (TMS), (2) change the DICOM tags to make the files compatible in the TMS system, (3) insert the kV-CBCT field to make the plan deliverable in the non-ART Linac. There are minimum remaining manual steps to setup the number of fractions to the intended number of IGRT fractions and to link plan to the prescription in TMS. We compare the required resources and the percentage of ART treatments on the oART system before and after the implementation of the proposed workflow to quantify the improvement of service.

RESULTS

The proposed workflow and automation eliminated the need to convert between IGRT/ART fractions in the Ethos system and reduced manual work by 25 minutes each adapted plan transfer. Table 1 summarizes the number of physics tasks and the percentage of ART fractions in oART system per month before and after the proposed workflow. This workflow reduced the physics IGRT/ART tasks from 107±31 to 65±21 tasks per month (p<0.05). Percentage of ART treatments on oART system increase from 30%±3% to 57%±13% (p<0.05). We also observed increased utilization of ART from 46% in the 1st month to 71% in the 6th month since it is easier to find a feasible time slot for the clinical team. The majority of the remaining IGRT on oART system are lung SBRT where the first fraction is not adapted due to being within a week of the simulation.

CONCLUSION

Leveraging CBCT based ART system as replan platform and non-ART Linac as IGRT platform is clinically feasible. This process significantly improved the turnaround time for replan, reduced the required resource and promotes the utilization of oART.

Machine Learning for the Prediction of Biochemical Recurrence in Patients Treated with Radical Prostatectomy

PURPOSE/OBJECTIVE(S)

Biochemical recurrence (BCR) occurs in about 40% of patients with prostate cancer following radical prostatectomy (RP). Our goal was to develop a machine learning model for the prediction of BCR five-years after RP, to improve patient prognostication.

MATERIALS/METHODS

Patients treated with RP at a tertiary care medical center between 1990 and 2017 were included. A gradient boosted decision trees-based machine learning model modified to handle survival data was trained on 80% of the dataset. The model's performance was evaluated on the remaining 20%. Input variables were age at surgery, prostate specific antigen (PSA) at diagnosis (in ng/mL), pathologic Gleason grade group (GG), pathologic T stage (organ confined disease vs. extracapsular extension (ECE) vs. seminal vesicle invasion (SVI)), lymph node involvement, and surgical margin status. Model performance was assessed using time-dependent area under curve of the receiver operator curve (AUC).

RESULTS

The full dataset included 11,139 patients, of whom 1,153 (10%) developed BCR. Median age at surgery was 59 and PSA at diagnosis was 5.4 ng/mL. Only 1,080 (9.7%) patients had GG 3, and 707 (6.3%) GG 4 and 5. 1,366 (12%) patients had positive surgical margins and 134 (1.2%) had lymph node involvement. Most patients had organ confined disease with EPE and SVI diagnosed in 2,759 (25%) and 392 (3.5%) patients, respectively. Median follow-up was 5 years and median time to BCR was 4 years. When validated on the hold-out set of 2,228 patients, the model shows a time-dependent AUC of 0.82 (95% CI 0.78 - 0.86) for BCR at t = 5 years.

CONCLUSION

Our machine learning model can be used to estimate risk of BCR following RP and shows exceptional performance, with implications on patient prognostication and follow-up. We are currently working on validating its performance on an external dataset.

Deep Learning-Based Quality Assurance for Auto-Segmentation Masks in Radiotherapy

PURPOSE/OBJECTIVE(S)

Deep learning-based auto-contouring has shown great promise in several disease sites including GU and head and neck. However, quality assurance (QA) is key to identify poor auto-contours which is time consuming. We hypothesis that training a deep learning model to predict contour quality metrics, such as Dice coefficients (DSC) and associated uncertainties for QA.

MATERIALS/METHODS

We trained a 3D U-Net-based DL model for segmenting the target and three clinical-relevant OARs (bladder and rectum). To mimic the slice-by-slice review process in clinical practice, we then trained a 2D ResNet-based DL model to predict the 2D DSC for each 2D slice's contour, generated by the 3D segmentation model. Using the Monte Carlo dropout technique, we made 20 independent predictions per slice, with the final DSC calculated as their average and uncertainty estimated as 95% prediction intervals (PI). The study cohort consisted of 912 prostate cancer patients who received definitive radiotherapy. The 3D auto-segmentation model was trained on 129 patients and validated on 20, before being tested on 763 patients. The 2D DSC prediction model was trained on 293 patients with 11116 slices, validated on 73 patients with 2804 slices, and tested on 366 patients with 14117 slices. Rectum was chosen to test the 2D contour QA model as it is the most challenging OAR. We categorized 2D slices into three groups based on the lower and upper bounds of the prediction intervals. "no/minor edits" (lower bound > = 0.9), "major edits" (lower bound < 0.9 and upper bound > = 0.8), and "not acceptable" (upper bound < 0.8). The model performance was quantified by calculating correlation coefficients between predicted and ground truth DSC and the fraction of cases that were correctly identified in each category.

RESULTS

The results of the study showed that the overall correlation coefficient between predicted, and ground truth DSC was 0.842. The model was able to correctly identify 78.3%, 60.7%, and 53.4% of the "no/minor edits", "major edits", and "not acceptable" cases, respectively.

CONCLUSION

This study provides a valuable tool for clinicians in making quick decisions on the acceptance, rejection, or revision of auto-segmented masks during the radiation therapy planning process by providing quantitative results on predicted DSC and associated uncertainties.