Improving Dose Volume Histogram (DVH) Based Analysis of Clinical Outcomes Using Modern Statistical Techniques: A Systematic Answer to Multiple Comparisons Concerns

PURPOSE/OBJECTIVE(S)

DVH constraints are essential in the clinical practice of radiation therapy. Historically, DVH constraints were found through sparse sampling of all possible DVH indices to find one that appeared to be most predictive for clinical toxicity. This approach can lead to inconsistent results among studies and to multiple comparison concerns. We aim to solve both problems by examining a full array of DVH indices using statistical methods that account for strong correlations among DVH indices and incorporate radiobiological knowledge constraints.

MATERIALS/METHODS

We extracted a dense array of V%_D indices from a treatment planning system using ESAPI interface, with V%_D corresponding to the volume fraction irradiated to dose D, or higher. We used Fused Lasso as the base model to compensate for correlations among DVH indices because it applies a penalty on the difference between DVH variables with adjacent dose. The base model was augmented with additional constraints based on radiobiological considerations: the positivity constraint (beta_i > 0) which assumes that any tissue irradiation cannot reduce the risk of toxicity, and monotonicity constraint (beta_i+1 > = beta_i) which assumes that higher dose to a fixed volume fraction cannot be associated with a lower risk of toxicity. We called the hybrid model KC-Lasso (Knowledge Constrained Lasso) and applied it to two clinical examples: grade 2 acute rectal toxicity in conventionally fractionated RT for 79 prostate cancer patients (77.4 Gy + MR based boost to 81-83 Gy) and cardiac toxicity in conventionally fractionated RT for 119 locally advanced Non-small Cell Lung Cancer (NSCLC) patients (Median prescribed dose 62 Gy). We further examined alternative data driven models to determine the importance of knowledge constraints.

RESULTS

KC-Lasso detected two distinct dose thresholds for grade 2 rectal toxicity, at 35 Gy and 78 Gy. A threshold of 51 Gy was detected for reduced overall survival due to cardiac irradiation in NSCLC patients. An examination of KC-Lasso models at varying step size suggested that a single mid-range index can be used as a treatment planning constraint while full model can be used for confirmatory, final plan evaluation. Alternative models which lack knowledge constraints show patterns of negative and isolated coefficients which are difficult to interpret and are not likely to be generalizable.

CONCLUSION

A more systematic approach to the analysis of correlations between DVH constraints and clinical toxicity can lead to greater consistency of results among different studies, better understanding of true dose thresholds and results which are more generalizable.

Reinforcement Learning Powered Station Parameter Optimized Radiation Therapy (SPORT): A Novel Treatment Planning and Beam Delivery Technique

PURPOSE/OBJECTIVE(S)

Conventional intensity modulated radiation therapy (IMRT) with a typical 5-20 fixed beams often does not provide sufficient angular sampling required for conformal dose shaping, whereas current volumetric modulated arc therapy (VMAT) discretizes the angular space into equally spaced control points without considering the differential need for intensity modulation of different angles, leading to undersampling at some angles while oversampling at some other angles. Our goal is to develop a node or station parameter optimized radiation therapy (SPORT) strategy with simultaneously optimized angular sampling and beam modulation by leveraging state-of-the-art reinforcement learning and the unique capability of modern digital LINACs in dose delivery through programmable nodal points.

MATERIALS/METHODS

We developed a SPORT optimization framework, in which, the process of programming control points (or station parameters) was formulated as a stochastic dynamic programming problem, which was solved by a reinforcement learning-based algorithm. On-policy reinforcement learning method, namely, state-action-reward-state-action (SARSA) was integrated with deep convolutional neural network to predict station parameters by utilizing the patient's anatomical structures meanwhile considering the delivery capability of a typical digital LINAC machine. Here, the deep convolutional neural network estimated the state-action value by using the quality of the plan with current station parameters when a next potential station parameter was selected. The state-action value was then updated by SARSA learning. The quality of the plan was quantified by dosimetry constraints. The model was assessed by a retrospective study on a cohort of patients underwent head-and-neck radiation therapy. Dosimetric analysis and delivery efficiency comparisons were used to evaluate the performance of the proposed framework.

RESULTS

Our model was used to generate 16 plans unseen in the original training set. All the plans predicted by our model achieved better dose distributions without violating clinical planning constraints. Moreover, instead of using 4 full standard arcs in the original clinically used plans obtained via manual optimization, the predicted plans only used one full standard arc (about 178 control points) plus boost from a few sub-arcs (less than 30 degrees of gantry angles), which significantly improved the efficiency of the beam delivery. We are in the process of integrating the sub-arcs into the full arc by considering the programmable capability of modern LINACs.

CONCLUSION

We demonstrated that a machine learning-based SPORT framework capable of optimizing the spatial sampling and beam modulation simultaneously for modern radiation therapy. The framework not only significantly improves the quality and efficiency of beam delivery, but also has the potential to be incorporated into current clinical workflow to improve the efficiency of dose planning and delivery.

Patient-Specific 3D CT Images Reconstruction from 2D KV Images Via Vision Transformer-Based Deep-Learning

PURPOSE/OBJECTIVE(S)

In some proton therapy facilities, patient alignment relies on two 2D orthogonal kV images, taken at fixed, oblique angles, as no 3D on-the-bed-imaging is available. The visibility of the tumor in kV images is limited since the patient's 3D anatomy is projected onto a 2D plane, especially when the tumor is behind a high-density structure such as bone. This can lead to a large patient setup error. A solution to this problem is to reconstruct the 3D CT image from the kV images obtained in the treatment position.

MATERIALS/METHODS

An asymmetric autoencoder-like network built with vision-transformer blocks was developed. The data was collected from a head and neck patient: 2 orthogonal kV images (1024X1024 voxels), 1 3D CT with padding (512X512X512) acquired from the in-room CT-on-rails before kVs were taken and 2 digitally-reconstructed-radiograph (DRR) images (512X512) based on the CT. We resampled kV images every 8 voxels and DRR and CT every 4 voxels, thus formed a dataset consisting of 262,144 samples, in which the images had a dimension of 128 for each direction. The value of each voxel in CT was normalized to range 0-1 with a uniform shift of 1000 and a denominator of 4000. For kV and DRR, we ranked all voxels value in an ascending order and normalized the values of the first 80% voxels to range 0-0.8 and the rest to range 0.8-1, thus yielding a quasi-Gaussian distribution, which was favorable by the deep neural networks. We further cropped kV and DRR images with a self-supervised bitmap based on the voxels' gradients. In training, both kV and DRR were utilized, and the encoder was encouraged to learn the same feature maps for kV images and its corresponding DRR images with mean-absolute-error (MAE) as the similarity loss. Then the decoder would reconstruct the 3D CT image from the feature maps of the kV images with the CT-on-rails as ground-truth (gCT) and MAE as the reconstruction loss. In testing, only independent kV images were used. The full-size synthetic CT (sCT) was achieved by concatenating the sCTs generated by the model according to their spatial information. The image quality of the sCT was evaluated using MAE and per-voxel-absolute-CT-number-difference volume histogram (CDVH). The proposed network was implemented with PyTorch deep learning library and both distributed data parallel (DDP) and automatic mixed precision (AMP) were applied to saving memory and accelerating the training speed. We used the AdamW optimizer with β1 = 0.9 and β2 = 0.999 and a cosine annealing learning rate scheduler with an initial learning of 1e-7 and 20 warm-up epochs.

RESULTS

The model achieved a MAE of <40HU and the CDVH showed that <5% of the voxels had a per-voxel-absolute-CT-number-difference larger than 185HU. The profile of a typical gCT slice and its corresponding sCT slice exhibited a high agreement, indicating the high similarity between the gCT and sCT.

CONCLUSION

A patient-specific vision-transformer-based network was developed and shown to be accurate and efficient to reconstruct 3D CT images from kV images.

An Efficient Transformer Model for Synthesizing Dual Energy CT from Single Energy Scanner

PURPOSE/OBJECTIVE(S)

Dual-energy CT can be used to optimize radiation treatment. Recently, deep learning has been demonstrated to synthesize high-energy CT images from low-energy ones for dose reduction and lower CT system burden. As the state-of-the-art deep learning architecture, the computation burden of Transformer increases quadratically with the feature size, making the model training resource-demanding or even infeasible. Here, we introduce an efficient transformer for the balance between CT image synthesis quality and computational burden.

MATERIALS/METHODS

The model is a U-shape deep neural network with encoders and decoders built by Transformer blocks. The model input is low-energy 100kVp CT image and the output is high-energy 140kVp one. Each block has a Self Channel Correlation Unit (SCCU) and a Self Spatial Attention Unit (SSAU). Local shortcuts are applied for both units. Under-sampling operation achieved by pixel shuffling is used to obtain multi-scale feature maps, and the transformer block is applied on each feature scale. Symmetric skip connection sending features from shallow layers to deep layers, thus an additional 1 × 1 convolution is used for feature fusion in each decoder. In a SCCU, the feature is first mapped to one Query, one Key, and one Value. Then the Query and the Key tensors perform matrix multiplication to compute cross covariance of feature channels. The channel correlation score can be obtained by normalization of the covariance, and it is used to weight the Value tensor. As a result, the model complexity only increases linearly with the feature size. Besides the channel weighting, we enhance spatial information using SSAU, where the feature is mapped to two tensors. One tensor after activation is used to point-wisely calibrate another tensor. Additional Transformer blocks are cascaded to the last decoder for feature refinement. Because of the structure similarity of low- and high-energy CT images, a global shortcut is used to ease model training. Clinical iodine contrast-enhanced dual energy CT image datasets of 19 patients are used in this study. The dual-energy scanning is performed by a SOMATOM Definition Flash DECT scanner. We split the datasets into training dataset of 15 patients, validation dataset of 1 patient, and testing dataset of 3 patients. The image size is 512 × 512 with pixel size 0.5 × 0.5 mm2.

RESULTS

The U-Net model with 1.95M parameters and 44.87G FLOPS achieved the averaged PSNR value of 44.55 dB (s.t.d. 1.34) and averaged RMSE value of 0.0060 (s.t.d. 0.001). In comparison, our efficient Transformer with 1.408M parameters and 31.375G FLOPS achieved the averaged PSNR value of 44.78 dB (s.t.d. 1.37) and RMSE value of 0.0059 (s.t.d. 0.001), demonstrating our model has better performance with small model size and less computation.

CONCLUSION

The efficient Transformer model allows high-resolution CT image synthesis with small model scale and computation burden from low-energy CT image.

Morin protects chicks with T-2 toxin poisoning by decreasing heterophil extracellular traps, oxidative stress and inflammatory response

1. Fusarium tritici widely exists in a variety of grain feeds. The T-2 toxin is the main hazardous component produced by Fusarium tritici, making a serious hazard to poultry industry. Morin, belonging to the flavonoid family, can be extracted from mulberry plants and possesses anticancer, antioxidant and anti-inflammatory compounds, but whether morin protects chicks with T-2 toxin poisoning remains unclear. This experiment firstly established a chick model of T-2 toxin poisoning and then investigated the protective effects and mechanism of morin against T-2 toxin in chicks.2. The function of liver and kidney was measured by corresponding alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), blood urea nitrogen (BUN), creatinine (Cre) and uric acid (UA) kits. Histopathological changes were observed by haematoxylin-eosin staining. The status of oxidative stress was measured by MDA, SOD, CAT, GSH and GSH-PX kits. The mRNA levels of TNF-α, COX-2, IL-1β, IL-6, caspase-1, caspase-3 and caspase-11 were measured by quantitative real-time PCR. Heterophil extracellular trap (HET) release was analysed by immunofluorescence and fluorescence microplate.3. The model with T-2 toxin poisoning in chicks was successfully established. Morin significantly decreased T-2 toxin-induced ALT, AST, ALP, BUN, Cre and UA, and improved T-2 toxin-induced liver cell rupture, liver cord disorder and kidney interstitial oedema. Oxidative stress analysis showed that morin ameliorated T-2 toxin-induced damage by reducing malondialdehyde (MDA), increasing superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione peroxidase (GSH-PX). The qRT-PCR analysis showed that morin reduced T-2 toxin-induced mRNA expressions of TNF-α, COX-2, IL-1β, IL-6, caspase-1, caspase-3 and caspase-11. Moreover, morin significantly reduced the release of T-2 toxin-induced HET in vitro and in vivo.4. Morin can protect chicks from T-2 toxin poisoning by decreasing HETs, oxidative stress and inflammatory responses, which make it a useful compound against T-2 toxin poisoning in poultry feed.

A Machine Learning Method to Predict Pathological Complete Response of Esophageal Cancer after Neoadjuvant Chemoradiotherapy with Clinicohematological Markers and MR Radiomics: A Multi-Center Study

PURPOSE/OBJECTIVE(S)

Nearly 30% of patients with local advanced esophageal cancer achieved pathological complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT), who may benefit from organ-preservation strategy under accurate prediction of pCR. We aimed to develop and validate machine learning models based on clinicohematological markers and MR radiomics to accurately predict pCR of esophageal cancer after nCRT.

MATERIALS/METHODS

In this multi-center study, eligible patients with esophageal cancer who received baseline MR scan (T2-weighted image) and nCRT plus surgery were enrolled between September 2014 and September 2022 at institution 1 (training set) and between December 2017 and August 2021 at institution 2 (testing set). Pre-nCRT and post-nCRT blood test results were collected to calculate hematological markers. Models were constructed by machine learning based on clinicohematological markers and MR radiomics to predict pCR. Area under the curve (AUC) and cut-off analysis were used to evaluate model performances.

RESULTS

Totally 154 patients (81 in the training set and 73 in the testing set) were enrolled. The combined model integrating pre-nCRT monocyte-to-lymphocyte ratio and 6 radiomics features achieved AUC of 0.800 (95% CI 0.671-0.918) in the testing set, with sensitivity of 79.2% (95% CI 62.5%-95.8%), specificity of 83.7% (95% CI 73.5%-93.9%), positive predictive value of 76.0% (95% CI 62.5%-90.0%), and negative predictive value of 89.6% (95% CI 82.0%-95.8%).

CONCLUSION

A machine learning model based on clinicohematological markers and MR radiomics to predict pCR after nCRT for patients with esophageal cancer was developed and validated, providing a novel tool for personalized treatment. It is necessary to further validate in more large datasets.

Polymetastatic Recurrence-Free Survival in Patients with Repeat Oligometastases on the SABR-5 Trial

PURPOSE/OBJECTIVE(S)

To determine polymetastatic recurrence-free survival (PMRFS) in patients with repeat oligometastases (OM) on the SABR-5 trial.

MATERIALS/METHODS

SABR-5 is a prospective, multi-center trial that evaluated the safety of stereotactic ablative radiotherapy (SABR) in patients with 1-5 OM or oligoprogressive lesions. On SABR-5, patients were followed post-SABR according to standardized protocols. Patients with repeat extra-cranial OM after metastasis-directed therapy (MDT; SABR, surgery, or thermoablation) to all initial OM (including those treated before enrolment on SABR-5) were identified. Exclusion criteria included history of multiple primary malignancies and incomplete re-staging. PMRFS was defined as time from presentation of repeat oligometastases to death or presentation of 6 or more progressing metastases, leptomeningeal metastases, lymphangitic carcinomatosis, malignant ascites, or malignant pleural effusion. PMRFS, overall survival (OS), and progression-free survival (PFS) were calculated using the Kaplan-Meier method.

RESULTS

Seventy-six patients with repeat OM were included, of which 44 (58%) received second MDT to all OM. The most common histology in patients who received second MDT was colorectal cancer (10/44 [23%]) and in those who did not was prostate cancer (17/32 [53%]). Patients who did vs. did not receive second MDT had fewer metastases at repeat OM (mean 1.3 vs 2.2; p<0.001) and no difference in time between initial OM and repeat OM (16 vs. 17 months; p = 0.74). For patients who received second MDT, median follow-up from presentation of repeat OM was 2.6 years. Median PFS after first and second MDT were 15 months (95% CI 11-18) and 11 months (95% CI 7-17), respectively. At last follow-up, 22/44 patients (50%) were alive without polymetastatic recurrence. 3-year PMRFS and OS from presentation of repeat OM were 51% (95% CI 33-66%) and 66% (95% CI 47-79%), respectively.

CONCLUSION

Patients presenting with repeat OM after MDT may still have favorable 3-year PMRFS and OS, which may justify exploring aggressive local treatments in this subpopulation. Further randomized trials in this space are needed.

Efficacy and Toxicity of Different Target Volume Delineations of Radiotherapy Based on the Updated RTOG/NRG and EORTC Guidelines in Patients with High Grade Glioma: A Randomized, Controlled Clinical Trial

PURPOSE/OBJECTIVE(S)

Postoperative radiotherapy with concomitant and adjuvant temozolomide (TMZ) is the standard of care for newly diagnosed high grade glioma, but the optimal method for target volume delineations for intensity modulated radiation therapy (IMRT) is still unclear. We hypothesized that compared with the EORTC guidelines, IMRT based on the updated RTOG/NRG guidelines was equally effective, without increasing toxicities for patients with high-grade glioma. The purpose of this randomized phase 2 study was to compare the efficacy and toxicity of IMRT based on different target volume delineations (updated RTOG/NRG versus EORTC guidelines) with concomitant and adjuvant TMZ for patients with high grade glioma.

MATERIALS/METHODS

A total of 302 patients with newly diagnosed high-grade glioma (WHO grade 3-4) were randomly assigned (1:1) to receive postoperative IMRT based on either updated RTOG/NRG guidelines (RTOG/NRG group, n = 151) or EORTC guideline (EORTC group, n = 151), with concomitant and adjuvant TMZ. In the RTOG/NRG group, an initial volume consisting of enhancement, postoperative cavity, plus surrounding edema (or fluid-attenuated inversion recovery [FLAIR] abnormality defined by magnetic resonance imaging [MRI]) and a 2-cm margin received 46 Gy in 23 fractions followed by a boost of 14 Gy in 7 fractions to the area of enhancement plus the cavity and a 2-cm margin. In the EORTC group, a single planning volume was used to deliver 60 Gy in 30 fractions to the area of enhancement and the cavity with a 2-cm margin. The primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS) and toxicities associated with each treatment.

RESULTS

No statistically significant differences were observed between groups for 1-year OS (71.8% for RTOG/NRG group and 69.9% for EORTC group, respectively; P = 0.759) or 1-year PFS (46.7% for RTOG/NRG group and 43.6% for EORTC group, respectively; P = 0.674). Efficacy did not differ by MGMT methylation status. There were no differences in grade 3-4 toxicities (leukopenia, lymphopenia, neutropenia, thrombocytopenia, fatigue, nausea and vomiting) between the two groups. No grade 5 toxicities were observed in both groups. Multivariate analyses showed that tumor MGMT status (methylated vs unmethylated) and WHO grade (grade 3 vs grade 4) were associated with OS and PFS. However, radiation type (RTOG/NRG group vs EORTC), sex, age, and Karnofsky scale did not significantly influence OS or PFS.

CONCLUSION

Compared with EORTC guidelines for postoperative radiotherapy, IMRT based on RTOG/NRG guidelines was equally effective, without increasing toxicities for patients with high-grade glioma. This trial is registered with chictr.org.cn, number ChiCTR2100046667.

High Resolution Imaging with Focused kV X-Rays for Small Animal Radio-Neuromodulation

PURPOSE/OBJECTIVE(S)

High precision radiotherapy for small animal radio-neuromodulation requires conformal treatment to very small targets down to 2.5 mm. A focused kV technique based on novel usage of polycapillary x-ray lenses can focus x-ray beams to <0.2 mm in diameter, which is ideal for such uses. Such application also requires high resolution CT images for treatment planning and setup, which was hard to achieve using conventional x-ray tube. In this work, we demonstrate the feasibility of using a virtual focal spot generated with an x-ray lens to perform high-resolution CBCT acquisition.

MATERIALS/METHODS

The experiment with x-ray lens was set up on an x-ray tabletop system to generate a virtual focal spot. A pinhole image was acquired for the virtual focal spot and compared with the one acquired with the conventional focal spot without the lens. The planar imaging resolution with and without the lens were evaluated using a line pair resolution phantom. The spatial resolution of the two settings were estimated by reconstructing a 0.15-mm wire phantom and comparing its full width half maximum (FWHM). A CBCT scan of a rodent head was also acquired to further demonstrate the improved resolution using the x-ray lens.

RESULTS

Compared to conventional imaging acquisition with a measured x-ray focal spot of 0.395 mm FWHM, the virtual focal spot size was measured at 0.175 mm. The reduction in focal spot size with lens leads to an almost doubled planar imaging resolution and a 26% enhancement in 3D spatial resolution. A realistic CBCT acquisition of a rodent head mimicked the imaging acquisition step for radio-neuromodulation and further showed the improved visualization for fine structures.

CONCLUSION

This work demonstrated that the focused kV x-ray technique was capable of generating small focal spot size of <0.2 mm. The proposed method provides an adaptive imaging platform to acquire x-ray and CBCT images for treatment planning and setup with improved spatial resolution compared to conventional CBCT image acquisition.

Chemoradiotherapy Combined with Nab-Paclitaxel plus Cisplatin in Patients with Locally Advanced Borderline Resectable or Unresectable Esophageal Squamous Cell Carcinoma: A Phase I/II Study

PURPOSE/OBJECTIVE(S)

To evaluate the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-PTX) plus cisplatin as the regimen of conversional chemoradiotherapy (cCRT) in locally advanced borderline resectable or unresectable esophageal squamous cell carcinoma (ESCC).

MATERIALS/METHODS

Patients with locally advanced ESCC (cT3-4, Nany, M0-1, M1 was limited to lymph node metastasis in the supraclavicular area) were enrolled. All the patients received the cCRT of nab-PTX plus cisplatin. After the cCRT, those resectable patients received esophagectomy; those unresectable patients continued to receive the definitive chemoradiotherapy (dCRT). The locoregional control (LRC), overall survival (OS), progression-free survival (PFS), distant metastasis free survival (DMFS), pathological complete response (pCR), R0 resection rate and adverse events (AEs) were calculated.

RESULTS

A total of 45 patients with ESCC treated from October 2019 to May 2021 were finally included. The median follow-up time was 30.3 months. The LRC, OS, EFS, DMFS at 1and 2 years were 81.5%, 86.6%, 64.3%, 73.2% and 72.4%, 68.8%, 44.8%, 52.7% respectively. 21 patients (46.7%) received conversional chemoradiotherapy plus surgery (cCRT+S). The pCR rate and R0 resection rate were 47.6% and 84.0%. The LRC rate at 1 and 2 years were 95.0%, 87.1% in cCRT+S patients and 69.3%, 58.7% in dCRT patients respectively (HR, 5.14; 95% CI, 1.10-23.94; P = 0.021). The OS rate at 1 and 2 years were 95.2% and 84.2% in resectable patients compared to 78.8% and 54.4% in unresectable patients (HR, 3.41; 95% CI, 1.10-10.61; P = 0.024). The toxicities during chemoradiotherapy were tolerated, the most common grade 3-4 toxicities were radiation esophagitis (15.6%).

CONCLUSION

Nab-PTX plus cisplatin were effective and safe as the regimen of conversional chemoradiotherapy of ESCC. The patients receiving conversional chemoradiotherapy plus surgery (cCRT+S) were prone to have a better survival.

Multi-Institutional Report of Re-Irradiation for Recurrent High-Grade Glioma

PURPOSE/OBJECTIVE(S)

Significant heterogeneity exists with regards to prior published reports of re-irradiation (re-RT) in patients with recurrent high grade glioma (HGG). A multi-institutional database of 10 academic centers across the United States was created to analyze prognostic outcomes for re-RT for recurrent HGG, which included WHO Grade III and Grade IV tumors.

MATERIALS/METHODS

Patients with HGG who had initially received standard radiotherapy (RT) and were subsequently treated with a course of re-RT at recurrence were included in the study. Factors assessed to delineate a significant association with overall survival (OS) and toxicity included age, KPS, number of relapses, dose, use of bevacizumab (BEV) or temozolomide (TMZ), time from prior RT, histology, RT target, re-RT target> 5cm and extent of resection, and MGMT methylation status. The Kaplan-Meier Method was used to estimate OS. Cox proportional hazards regression models were used to identify factors associated with OS. Toxicity outcomes were assessed using logistic regression. Significance was assumed if p<0.05. Data management and decision management software were used for all analyses.

RESULTS

Between 2001 and 2022, 280 patients from 10 academic institutions were treated with re-RT for diagnosis of recurrent HGG. 133 patients (71.1%) had a histologic glioblastoma (GBM) at the time of re-RT, with the remainder having Grade 3 gliomas. Median dose delivered at re-RT was 47 Gy BED10 (IQR 47 - 53 Gy BED10), with the most common regimen being 35 Gy in 10 fractions. 83 patients (56%) had GTV greater than 5 cm treated with re-RT. 183 patients (79%) received concurrent systemic therapy, including 95 (41%) who received concurrent TMZ and 86 (45%) who received concurrent BEV. Median OS for the entire cohort was 10 months. Increasing dose at re-RT was associated with improved OS (OR 0.80 95% CI 0.67-0.95, p = 0.10 per 10 Gy BED10), as was dose greater than 47 Gy BED10, which is equivalent to 35 Gy in 10 fractions (OR 0.70, 95% CI 0.54-0.91). Concurrent TMZ was also associated with improved OS (OR 0.68, 95% CI 0.46-0.83, p < 0.01). 32/143 (22%) patients evaluable for toxicity experienced Grade 2 or greater adverse radiation effect (ARE). Use of BEV was associated with decreased toxicity (OR 0.45, 95% CI 0.21-0.98, p = 0.05). Dose at re-RT (OR 1.07 per 10 Gy BED10, p = 0.78), a GTV > 5cm (OR 1.39, p = 0.44), and the use of concurrent TMZ (OR 1.90, p = 0.10) were not associated with Grade 2 or greater ARE.

CONCLUSION

Higher dose of re-RT and use of concurrent TMZ led to improved OS in recurrent HGG patients without an associated increased rate of ARE. Use of BEV decreased the likelihood of Grade 2 or greater ARE in the re-RT setting for these recurrent HGG patients.

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the 'arrow of time' that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11-13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.

[The application of ultrasound in the diagnosis of small bowel volvulus in adults]

Objective: To analyze the ultrasound characteristics of small bowel volvulus among adults and to investigate the value of ultrasound in the diagnosis of small bowel volvulus. Methods: Totally 34 adults with small bowel volvulus confirmed by clinical diagnosis or surgery and who underwent ultrasound examination at Peking Union Medical College Hospital from August 2017 to October 2022 were enrolled, including 19 males and 15 females, aged (55.0±21.8) years (range: 19 to 94 years). The clinical characteristics, CT images and ultrasound images of the patients were retrospectively reviewed, and the ultra, sound features of small bowel volvulus and its diagnostic efficacy were analyzed. Results: Abdominal pain was the typical clinical symptom of all patients. Other symptoms included 21 cases of abdominal distension, 19 cases of nausea and vomiting, and 13 cases of cessation of passage of stool or flatus. Eight patients had signs of peritonitis and 22 patients had abnormal bowel sounds. Twenty patients had a history of abdominal surgery. Twenty-seven patients underwent surgery for intestinal obstruction, and the remaining 7 patients improved after conservative treatment. All cases were evaluated by ultrasound, 11 cases showed a "whirl sign" and were diagnosed as small bowel volvulus, the diagnostic accuracy rate was 32.4% (11/34), ultrasound simultaneously diagnosed intestinal obstruction in 21 cases, 17 cases of abdominal effusion, 4 cases of intestinal wall thickening, 2 cases of abdominal mass, 1 case of intussusception, 1 case of right sided inguinal hernia. CT and ultrasound had a consistent positive discovery in 88.2% (30/34) of all the patients. Conclusion: Ultrasound is valuable in the diagnosis of small bowel volvulus and the evaluation of complications.

The Impact of Intra-Fraction Bowel Motion on Luminal Gastrointestinal Organ at Risk Dosimetry When Using Stereotactic Adaptive Radiotherapy for Abdominal Malignancies

PURPOSE/OBJECTIVE(S)

Daily online adaptive radiotherapy (ART) provides inter-fraction motion management of the luminal gastrointestinal (GI) structures when delivering abdominal SBRT. One potential drawback of ART is the time-consuming process, and intra-fraction GI changes from completion of the ART process to the end of treatment delivery have not been thoroughly evaluated. We explored intra-fraction bowel motion for patients receiving abdominal stereotactic adaptive radiotherapy (sART) MATERIALS/METHODS: Six patients with abdominal malignancies treated with CT-guided sART on a prospective feasibility trial had additional CBCT's acquired post-treatment (pTx-CBCT). All patients were prescribed to 50 Gy/5 fractions (fx), and the constraint for all GI OARs was V33≤0.5 cc. Time from initial CBCT (I-CBCT) used for adaptive planning to pTx-CBCT was collected. The luminal GI OAR (stomach (S), duodenum (D), small bowel (SB), and large bowel (LB)) were retrospectively contoured on pTx-CBCT. The OAR doses were compared between the I-CBCT and pTx-CBCT. The adaptive plan (PA) and initial plan (PI) doses were overlayed on the pTx-CBCT contours. The PA pTx-CBCT OAR doses were then compared to the PI pTx-CBCT OAR doses. A Boolean OAR structure of all GI OARs was evaluated to remove potential differences in structure definitions between providers. The T-test was used to compare differences in instances of D0.5cc ≥ 33 and 50 Gy. Patient charts were reviewed for grades (G) ≥ 3 toxicity.

RESULTS

Thirty fractions (fx) of sART were delivered and pTx-CBCT were acquired in 26 fx. Mean time from I-CBCT to pTx-CBCT acquisition was 66 min (38-98 min). On average at 0.5 cc the PA overdosed the S by 1.74 Gy based on pTx-CBCT anatomy compared to 2.35 Gy by the PI, the D by 0.47 Gy (PA) vs .84 Gy (PI), the SB by 1.14 Gy (PA) vs 1.43 Gy (PI), and the LB by 0.13 Gy (PA) vs 0.60 Gy (PI). The dose to the Boolean OAR structure was on average 2.51 Gy/fx higher than expected when overlaying the PA on the pTx-CBCT compared to 3.38 Gy/fx higher when overlaying the PI on the pTx-CBCT. There was no significant difference in the instance of the PA exceeding D0.5 cc ≥33 Gy vs the PI (p = 0.083), but the PA significantly reduced the instances of D0.5cc≥50 Gy (p = 0.001) compared to the PI. No patient experienced G≥3 toxicity at a median follow-up of 8 months (3-12).

CONCLUSION

These data demonstrate sART led to a significant decrease in dose to GI OARs, particularly for prescription dose or greater, even after accounting for intra-fractional bowel motion. While both the PI and the PA violated the V33 luminal GI OAR constraint in approximately ½ of pTx-CBCTs, the fraction of OARs receiving at least 50 Gy was significantly higher when overlaying the PI compared to the PA. While no G3 toxicities were reported in this small cohort, further studies are needed to characterize if the increased dose to GI OARs over the expected dose is clinically significant.

A novel bivalent anti-c-MET/PD-1 bispecific antibody exhibits potent cytotoxicity against c-MET/PD-L1-positive colorectal cancer

Previously, we generated a novel bispecific antibody (BsAb) simultaneously targeting both c-MET and PD-1 (PDCD1), which can bridge T cells and c-MET positive tumor cells. However, the specific mechanisms and antitumor activities of the BsAb against c-MET/PD-L1 (CD274) positive colorectal cancer (CRC) is not completely understood. In this study, in addition to the tumor intrinsic mechanism investigation with molecular biology assay in vitro, a humanized mouse model was used to evaluate antitumor activity of the BsAb in vivo. The BsAb could inhibit c-MET/PD-L1+ CRC cell migration and show strong antitumor activity against HCT116 tumors in mice, potentially by inducing the degradation of c-MET protein in a dose and time-dependent manner. The BsAb could suppress the phosphorylation of c-MET downstream proteins GRB2-associated-binding protein 1 (Gab1) and focal adhesion kinase (FAK). Considering the tumor extrinsic mechanism, the BsAb may promote phagocytosis of macrophage. Furthermore, the level of plasma exosomal-c-MET/PD-L1 is able to distinguish CRC patients from healthy controls. In summary, the BsAb exhibited potent anti-tumor activities by two distinguished mechanisms: inhibition of c-MET signal transduction and promotion of macrophage-mediated phagocytosis. Our BsAb may provide a novel therapeutic agent for patients with c-MET/PD-L1+ CRC, and the status of exosomal-c-MET/PD-L1 can serve as a biomarker to predict responsiveness to treatment of our BsAb.

A Model of Type II Collagen-Induced Spondylitis and Arthritis in F1 Hybrid Male Mice

In this study, we tested a new model of ankylosing spondylitis in order to determine its histological and radiological features needed to investigate peripheral arthritis, spondylitis, and formation of the new bone tissues. F1 hybrid male mice (BALB/c×DBA/1), a progeny of spondylitis-susceptible BALB/c male mice and rheumatoid arthritis-susceptible DBA/1 female mice, were immunized intraperitoneally with bovine type II collagen (CII) mixed with adjuvant dimethyldioctadecylammonium bromide. Radiological and histological studies were performed at the peak of swelling, redness, and stiffness. The incidence of peripheral arthritis and spondylitis induced by CII in F1 hybrid mice were 66 and 62%, respectively. X-ray examination revealed bone erosion and spondylitis in the peripheral joints, as well as the formation of new bone tissues in the coccygeal vertebrae and between LIII and LIV vertebrae. The histological study showed lymphocyte and plasma cell infiltration, capillary dilation, congestion, and endochondral ossification of the lumbar vertebrae. This novel model of CII-induced spondylitis in F1 hybrid mice provoked axial and peripheral arthritides inducing chronic inflammation. In this model, the formation of new bone tissue in the stiff spine is characterized by endochondral ossification. The advanced model is an additional and valuable tool for investigation of the autoimmune reactions in spondylitis.

Activation of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 6 by Porphyromonas gingivalis regulates programmed cell death in epithelium

Background/purpose

Gingival epithelial cells form a physiological barrier against bacterial invasion. Programmed cell death (PCD) regulated by pathogen precognition receptors (PRRs) lead to tissue destruction and is closely related to inflammatory diseases. The purpose of this study was to investigate whether nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 6 (NLRP6) expresses in periodontal epithelium and induces PCD of epithelial cells infected by Porphyromonas gingivalis (P. gingivalis), therefore involves in periodontitis.

Material and methods

The expression of NLRP6 was detected in periodontal epithelium from human gingival sections and HaCaT cells stimulated by P. gingivalis. NLRP6 was over-expressed by adenovirus infection in HaCaT or knocked down by siRNA in P. gingivalis infected HaCaT, and the cell death was observed by transmission electron microscopy and flow cytometry analysis. In addition, qPCR and Western blot were performed to determine the expression of NLRP6 and the pyroptosis excutors, caspase-1 and gasdermin D. Enzyme-linked immunosorbent assay were performed to detect the secretion of IL-1β and IL-18.

Results

NLRP6 was up-regulated in both gingival epithelium of patients with periodontitis and P. gingivalis infected HaCaT. Over-expression of NLRP6 in HaCaT led to caspase-1 dependent pyroptosis. Interestingly, knockdown of NLRP6 with siRNA followed by P. gingivalis stimulation inhibited pyroptosis and induced apoptosis.

Conclusion

Up-regulation of NLRP6 by P. gingivalis in HaCaT led to pyroptosis, while knocking down NLRP6 inhibited pyroptosis and induced apoptosis, which indicated this PRR may play a crucial role in periodontitis by regulating PCD in periodontal epithelium.

CTGF promotes the repair and regeneration of alveoli after acute lung injury by promoting the proliferation of subpopulation of AEC2s

BACKGROUND

Functional alveolar regeneration is essential for the restoration of normal lung homeostasis after acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Lung is a relatively quiescent organ and a variety of stem cells are recruited to participate in lung repair and regeneration after lung tissue injury. However, there is still no effective method for promoting the proliferation of endogenous lung stem cells to promote repair and regeneration.

METHODS

Using protein mass spectrometry analysis, we analyzed the microenvironment after acute lung injury. RNA sequencing and image cytometry were used in the alveolar epithelial type 2 cells (AEC2s) subgroup identification. Then we used Sftpc+AEC2 lineage tracking mice and purified AEC2s to further elucidate the molecular mechanism by which CTGF regulates AEC2s proliferation both in vitro and in vivo. Bronchoalveolar lavage fluid (BALF) from thirty ARDS patients who underwent bronchoalveolar lavage was collected for the analysis of the correlation between the expressing of Krt5 in BALF and patients' prognosis.

RESULTS

Here, we elucidate that AEC2s are the main facultative stem cells of the distal lung after ALI and ARDS. The increase of connective tissue growth factor (CTGF) in the microenvironment after ALI promoted the proliferation of AEC2s subpopulations. Proliferated AEC2s rapidly expanded and differentiated into alveolar epithelial type 1 cells (AEC1s) in the regeneration after ALI. CTGF initiates the phosphorylation of LRP6 by promoting the interaction between Krt5 and LRP6 of AEC2s, thus activating the Wnt signaling pathway, which is the molecular mechanism of CTGF promoting the proliferation of AEC2s subpopulation.

CONCLUSIONS

Our study verifies that CTGF promotes the repair and regeneration of alveoli after acute lung injury by promoting the proliferation of AEC2s subpopulation.

[Clinical effects of expanded frontal flap and flip scar flap in repairing partial nasal defect]

Objective: To investigate the clinical effects of expanded frontal flap and flip scar flap in repairing partial nasal defect. Methods: A retrospective observational study was conducted. From January 2012 to January 2022, 26 patients with partial nasal defects who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 19 males and 7 females, aged 5 to 61 years. The surgery was performed in 4 stages. In the first stage, a rectangular skin and soft tissue expander (hereinafter referred to as expander) with suitable rated capacity was planted in frontal region and expanded by injecting water regularly. In the second stage, flip scar flap was grafted to reconstruct nasal inner lining, whose area was about 10% larger than the area of defect. The expanded frontal flap with pedicle was transferred to repair the nasal defect, whose pedicle was supraorbital vessel or supratrochlear vessel on the contralateral side of the defect, and the area of expanded flap was 20% larger than the nasal defect area after resection and flipping of scar flap. The donor site of expanded flap was sutured directly. After 3 weeks of flap transferring, the flap was delayed in the third stage. After 1 week of delaying operation, the pedicle of flap was cut off in the fourth stage. The number, rated capacity, injection volume, and expansion time of embedded expanders were recorded. The occurrences of complications including infection, hematoma, ulceration of expanded flap after the first stage operation, and blood supply disorder or necrosis of flap after operation in the second and fourth stages were observed. All the patients were followed up for 1 year at least, and the color of flap, scar of frontal donor site, symmetry of bilateral eyebrows, and the nasal appearance and ventilated function of external nasal tract were observed. Results: A total of 26 expanders were embedded in 26 patients. The rated capacity of expanders ranged from 100 to 300 mL. The injection volume was 1.0 to 1.5 times of the rated capacity of expanders. The expansion time ranged from 2.5 to 4.0 months, with an average time of 3 months. There were no complications occurred after each operation. The follow-up showed that the color of flap was similar to the normal nasal skin, the scar of frontal region was not obvious, the bilateral eyebrows were basically symmetrical, the nose had excellent appearance, ventilation function of external nasal tract was not affected, while some of the patients had downward rotation or unapparent tip-defining point of nose. Conclusions: Using the flip scar flap to reconstruct the nasal inner lining and pre-expanded frontal flap to reconstruct the nasal skin, without free cartilage transplantation to repair the partial nasal defects can achieve satisfied nasal appearance post operation, without abnormal external nasal ventilation function.

Better safe than so ray: national survey of radiation protection amongst interventional radiology trainees in the United Kingdom

OBJECTIVE

To establish the provision and use of radiation personal protective equipment (PPE) and dosimetry amongst UK interventional radiology (IR) trainees and highlight areas of improvement in order to enhance the radiation safety.

METHODS

A survey questionnaire was designed by members of the British Society of Interventional Radiology (BSIR) trainee committee via survey monkey and distributed to UK IR trainees via the BSIR membership mailing list, local representatives and Twitter. The survey was open from 04/01/2021 to 20/02/2021. Only IR trainees in years ST4 and above were included.

RESULTS

Of the 73 respondents, 62 qualified for analysis. Respondents (81% male) spent a median of 5.5 sessions (half day list) per week in the angiography suite and 58% (n=36) had difficulty finding appropriately sized lead aprons at least once a week. Overall 53% (n=33) had concerns about their radiation PPE. Furthermore 56% of trainees (n=35) experienced back pain among other symptoms attributed to wearing the lead aprons available to them. 77% (n=48) regularly wore lead glasses. For trainees requiring prescription glasses (n=22) overfit goggles were provided however 17 (77%) of these trainees felt the goggles compromised their ability to perform the procedure. Eye and finger dosimeters were used by 50% and 52% of respondents respectively. Compliance with body dosimetry was 99%.

CONCLUSION

Provision of radiation PPE and dose monitoring for IR trainees is suboptimal, particularly access to adequate eye protection or suitably fitting leads. Based on the findings of this survey, recommendations have been made to promote the safety and radiation awareness of IR trainees.

ADVANCES IN KNOWLEDGE

Radiation protection practices for IR trainees nationally are poor. Provision of suitable eye protection and well fitting lead body protection is low.

Diagnostic efficacy of lung ultrasound in cardiogenic pulmonary edema: a systematic review and meta-analysis

OBJECTIVE

This meta-analysis was performed to evaluate the diagnostic efficacy of lung ultrasound (LUS) in cardiogenic pulmonary edema.

MATERIALS AND METHODS

An electronic search of databases, including MEDLINE, Embase, PubMed, and Web of Science, was performed to collect clinical studies on ultrasound diagnosis of cardiogenic pulmonary edema from inception to 23 March 2023. The number of patients with true-positive, true-negative, false-positive, and false-negative cardiogenic pulmonary edema diagnosed by LUS was collected, and the R package was used to analyze the diagnostic efficacy of LUS.

RESULTS

Nine pieces of literature were finally included with 2,097 participants, including 1,047 patients with cardiogenic heart failure. Across the nine included papers, the pooled sensitivity of LUS in the included studies was 0.92 (95% CI: 0.84, 0.97) with a maximum sensitivity of 0.99 (95% CI: 0.96 to 1.00) and a minimum of 0.59 (95% CI: 0.50, 0.68). The pooled specificity of the included studies was 0.87 (95% CI: 0. 82, 0.91) with a maximum specificity of 0.93 (95% CI: 0.90-0.95) and a minimum of 0.80 (95% CI: 0.67, 0.89). The pooled AUC was 0.93 (95% CI: 0.84 to 0.97), suggesting a high diagnostic value of LUS in cardiogenic pulmonary edema.

CONCLUSIONS

Lung ultrasound offers a good diagnostic efficacy for cardiogenic pulmonary edema. Further standardization of the examination method is required to provide a reference for the clinical use of LUS.

[Efficacy and safety of programmed death-1 inhibitor in the treatment of relapsed/refractory classical Hodgkin's lymphoma]

Objective: This retrospective, single-center study aimed to evaluate the efficacy and safety of programmed death-1 (PD-1) inhibitors, either as monotherapy or in combination with chemotherapy, in the management of relapse/refractory classical Hodgkin's lymphoma (R/R cHL) . Methods: A total of 35 patients with R/R cHL who received treatment at the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College from September 2016 to December 2020 were enrolled in this study. Among them, 17 patients received PD-1 inhibitor monotherapy (PD-1 inhibitor group), while 18 patients received a combination of PD-1 inhibitor and chemotherapy (PD-1 inhibitor + chemotherapy group). Clinical data and follow-up information were retrospectively analyzed, and survival analysis was conducted using the Kaplan-Meier method and Cox proportional hazards model. Results: The median age of the 35 patients with R/R cHL was 29 years (range: 11-61 years), with 54.3% being male. According to the Ann Arbor staging system, 62.9% of patients presented with advanced (stage Ⅲ/Ⅳ) disease, and 48.6% had extranodal involvement. Before PD-1 inhibitor therapy, the median number of prior lines of therapy was 2 (range: 1-3). Objective responses were observed in 28 patients, including 22 complete response (CR) cases, resulting in an overall response rate (ORR) of 80.0% and a CR rate of 62.9%. Specifically, the ORR and CR rates were 64.7% and 58.8%, respectively, in the PD-1 inhibitor group and 94.4% and 66.7%, respectively, in the PD-1 inhibitor + chemotherapy group. Among the 18 patients who underwent sequential autologous hematopoietic stem cell transplantation (auto-HSCT) [13 CR and five partial response (PR) cases], eight patients received PD-1 inhibitor therapy after auto-HSCT as consolidation therapy. All patients maintained a CR status after transplantation, and they exhibited significantly improved progression-free survival (PFS) rates compared with those who did not undergo sequential auto-HSCT (4-year PFS rates: 100% vs 53.5% ; P=0.041). The incidence of immune-related adverse events was 29%, with only one patient experiencing grade≥3 adverse reactions, which indicated a favorable safety profile for the treatment approach. Conclusions: PD-1 inhibitor monotherapy demonstrates notable efficacy and sustained response in patients with R/R cHL. PD-1 inhibitors combined with chemotherapy significantly improve response rates. Additionally, for salvage therapy-sensitive patients, consolidation treatment with PD-1 inhibitors after auto-HSCT exhibits the potential for prolonging PFS.

Discrete unified gas-kinetic wave-particle method for flows in all flow regimes

This work proposes a discrete unified gas-kinetic wave-particle (DUGKWP) method for simulation of flows in all flow regimes. Unlike the discrete velocity method (DVM) and the direct simulation Monte Carlo (DSMC) method which solve the governing equations by either the deterministic method or the stochastic method, the DUGKWP combines the advantages of these two methods. In the DUGKWP, the information of microscopic particles as well as macroscopic flow variables are both evolved. Specifically, the microscopic particles are updated by the free-transport and resampling processes, while the macroscopic flow properties are evolved via solving the macroscopic governing equations of conservation laws with the finite volume method. According to the discrete characteristic solution to the Boltzmann-BGK equation utilized in the DUGKWP, in the highly rarefied flow regime, the motion of microscopic particles greatly determines the fluxes for the macroscopic governing equations. Conversely, for the continuum flow, no microscopic particle exists in the computational domain and the DUGKWP is degraded to the Navier-Stokes solver. Numerical studies validate that the DUGKWP can accurately predict the flow properties in all flow regimes. Furthermore, compared with the deterministic method, the DUGKWP enjoys superior efficiency with less memory consumption for both high-speed rarefied flows and flows close to the continuum regime.