Purpose To extract and study comprehensive spatial–temporal 18F-FDG PET features for the prediction of pathologic tumor response to neoadjuvant chemoradiotherapy (CRT) in esophageal cancer. Methods and Materials Twenty patients with esophageal cancer were treated with trimodality therapy (CRT plus surgery) and underwent FDG PET/CT scans both before (pre-CRT) and after (post-CRT) CRT. The two scans were rigidly registered. A tumor volume was semiautomatically delineated using a threshold of standardized uptake value (SUV) ≥ 2.5, followed by manual editing. Comprehensive features were extracted to characterize the SUV intensity distribution, spatial patterns (texture), tumor geometry, and associated changes resulting from CRT. The usefulness of each feature in predicting pathologic tumor response to CRT was evaluated using the area under the receiver operating characteristic curve (AUC). Results The best traditional response measure was maximum SUV (SUVmax) decline (AUC 0.76). Two new intensity features (SUVmean decline and skewness) and three texture features (inertia, correlation, and cluster prominence) were found to be significant predictors with AUCs ≥ 0.76. According to these features, a tumor was more likely a responder when the mean SUV decline was larger, when there were relatively fewer voxels with higher SUVs pre-CRT, or when FDG uptake post-CRT was relatively homogeneous. All of the most accurate predictive features were extracted from the entire tumor rather than from the most active part of the tumor. For SUV intensity features and tumor size features, changes were more predictive than pre- or post-CRT assessments alone. Conclusion Spatial–temporal FDG PET features were found to be useful predictors of pathologic tumor response to neoadjuvant chemoradiotherapy in esophageal cancer. Key words: FDG PET/CT, Tumor response, Esophageal cancer, Quantitative image analysis
Detailed analysis of the evolution characteristics of landscape ecological risk is crucial for coastal sustainable management and for understanding the potential environmental impacts of a man-made landform landscapes (MMLL). As a typical open coastal wetland, large-scale human activities (e.g., tidal reclamation, fishery activities, wind farm construction, and port construction) have substantially affected the evolution of the coastal ecological environment. Previous landscape ecological risk assessment studies have documented the effectiveness of assessing the quality of ecological environment processes. However, these studies have either focused on the noncoastal zone, or they have not considered the evolution of the spatial characteristics and ecological risk evolution of the landscape at an optimal scale. Here, we present a landscape ecological risk pattern (LERP) evolution model, based on two successive steps: first, we constructed an optimal scale method with an appropriate extent and grain using multi–temporal Landsat TM/OLI images acquired in the years 2000, 2004, 2008, 2013 and 2017, and then we calculated landscape ecological risk indices. Based on this model, the entire process of the spatiotemporal evolution of ecological risk patterns of the open coastal wetlands in Jiangsu, China, was determined. The principal findings are as follows: (1) The main landscape types in the study area are tidal flats and farmland, and the main features of the landscape evolution are a significant increase in aquafarming and a substantial decrease in the tidal flat area, while the landscape heterogeneity increased; (2) In the past 20 years, the areas of low and relatively low ecological risk in the study region were greatly reduced, while the areas of medium, relatively high, and high ecological risk greatly increased; the areas of high-grade ecological risk areas are mainly around Dongtai and Dafeng; (3) The area of ecological risk from low-grade to high-grade occupied 71.75% of the study area during 2000–2017. During the previous periods (2000–2004 and 2004–2008), the areas of low-grade ecological risk were transformed to areas of middle-grade ecological risk area, while during the later periods (2008–2013 and 2013–2017) there was a substantial increase in the proportion of areas of high-grade ecological risk. Our results complement the official database of coastal landscape planning, and provide important information for assessing the potential effects of MMLL processes on coastal environments.
Purpose We share our experiences on uniformly implementing an effective and efficient SGRT procedure with a new clinical workflow for treating breast patients in deep‐inspiration breath‐hold (DIBH) among 9 clinical centers using 26 optical surface imaging (OSI) systems. Methods Our procedures have five major components: (1) acquiring both free‐breathing (FB) and DIBH computed tomography (CT) at simulation to quantify the rise of the anterior surface, (2) defining uniformly a large region of interest (ROI) to accommodate large variations in patient anatomy and treatment techniques, (3) performing two‐step setup in FB by first aligning the arm and chin to minimize breast deformation and reproduce local lymphnode positions and then aligning the ROI, (4) aligning the vertical shift precisely from FB to DIBH, and (5) capturing a new on‐site reference image at DIBH to separate residual setup errors from the DIBH motion monitoring uncertainties. Moreover, a new clinical workflow was developed for patient data preparation using 4 OSI offline workstations without interruption of SGRT treatment at 22 OSI online workstations. This procedure/workflow is suitable for all photon planning techniques, including 2‐field, 3‐field, 4‐field, partial breast irradiation (PBI), and volumetric‐modulated arc therapy (VMAT) with or without bolus. Results Since 2019, we have developed and applied the uniform breast SGRT DIBH procedure with optimized clinical workflow and ensured treatment accuracy among the nine clinics within our institution. About 150 breast DIBH patients are treated daily and two major upgrades are achieved smoothly throughout our institution, owing to the uniform and versatile procedure, adequate staff training, and efficient workflow with effective clinical supports and backup strategies. Conclusion The uniform and versatile breast SGRT DIBH procedure and workflow have been developed to ensure smooth and optimal clinical operations, simplify clinical staff training and clinical troubleshooting, and allow high‐quality SGRT delivery in a busy multi‐center institution.
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