Comparison of Image Registration Based Measures of Regional Lung Ventilation from Dynamic Spiral CT with Xe-CT

Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this article, we propose a new regional measure of lung mechanics --- the specific air volume change by corrected Jacobian. Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration-based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). Results: After registration, the mean registration error is on the order of 1 mm. For cubical ROIs in cubes with size 20 mm $\times$ 20 mm $\times$ 20 mm, the SAJ and SACJ measures show significantly higher correlation (linear regression, average $r^2=0.75$ and $r^2=0.82$) with the Xe-CT based measure of specific ventilation (sV) than the SAI measure. For ROIs in slabs along the ventral-dorsal vertical direction with size of 150 mm $\times$ 8 mm $\times$ 40 mm, the SAJ, SACJ, and SAI all show high correlation (linear regression, average $r^2=0.88$, $r^2=0.92$ and $r^2=0.87$) with the Xe-CT based sV without significant differences when comparing between the three methods. Conclusion: Given a deformation field by an image registration algorithm, significant differences between the SAJ, SACJ, and SAI measures were found at a regional level compared to the Xe-CT sV in four sheep that were studied

Decision-Making of Transnational Supply Chain Considering Tariff and Third-Party Logistics Service

Countries’ economic policies, such as tariff barriers, have a profound impact on the global economy and international trade. The imposition of tariffs seriously disturbs the global trade and supply chain operations. This paper studies a supply chain composed of an overseas manufacturer, a domestic supplier and a third-party integrated international logistics service provider. A three-level decentralized leader-follower decision-making model and its variant--leader-follower alliance decision-making models are established, and the influences of revenue sharing and cost sharing on the three-level decentralized decision-making are analyzed. The results show that it is difficult for the supply chain to achieve coordination when the transportation and insurance costs are considered in the tariff cost. The increase of tariff rates will reduce the profits of all parties and the overall profit of the supply chain, and weaken the dominant position of the supplier in the supply chain. Revenue sharing can improve the supply chain performance; the performance of the whole supply chain cannot be improved or may even deteriorate by sharing the transportation cost alone. The study can provide practitioners with implications for how to carry effective cooperation and coordination in the supply chain and how to effectively reduce the influence of tariffs in the global trade system

Decision-Making of Transnational Supply Chain Considering Tariff and Third-Party Logistics Service

Countries’ economic policies, such as tariff barriers, have a profound impact on the global economy and international trade. The imposition of tariffs seriously disturbs the global trade and supply chain operations. This paper studies a supply chain composed of an overseas manufacturer, a domestic supplier and a third-party integrated international logistics service provider. A three-level decentralized leader-follower decision-making model and its variant--leader-follower alliance decision-making models are established, and the influences of revenue sharing and cost sharing on the three-level decentralized decision-making are analyzed. The results show that it is difficult for the supply chain to achieve coordination when the transportation and insurance costs are considered in the tariff cost. The increase of tariff rates will reduce the profits of all parties and the overall profit of the supply chain, and weaken the dominant position of the supplier in the supply chain. Revenue sharing can improve the supply chain performance; the performance of the whole supply chain cannot be improved or may even deteriorate by sharing the transportation cost alone. The study can provide practitioners with implications for how to carry effective cooperation and coordination in the supply chain and how to effectively reduce the influence of tariffs in the global trade system

Dosimetric differences in flattened and flattening filter-free beam treatment plans

This study investigated the dosimetric differences in treatment plans from flattened and flattening filter-free (FFF) beams from the TrueBeam System. A total of 104 treatment plans with static (sliding window) intensity-modulated radiotherapy beams and volumetric-modulated arc therapy (VMAT) beams were generated for 15 patients involving three cancer sites. In general, the FFF beam provides similar target coverage as the flattened beam with improved dose sparing to organ-at-risk (OAR). Among all three cancer sites, the head and neck showed more important differences between the flattened beam and FFF beam. The maximum reduction of the FFF beam in the mean dose reached up to 2.82 Gy for larynx in head and neck case. Compared to the 6 MV flattened beam, the 10 MV FFF beam provided improved dose sparing to certain OARs, especially for VMAT cases. Thus, 10 MV FFF beam could be used to improve the treatment plan

Tracking Regional Tissue Volume and Function Change in Lung Using Image Registration

We have previously demonstrated the 24-hour redistribution and reabsorption of bronchoalveolar lavage (BAL) fluid delivered to the lung during a bronchoscopic procedure in normal volunteers. In this work we utilize image-matching procedures to correlate fluid redistribution and reabsorption to changes in regional lung function. Lung CT datasets from six human subjects were used in this study. Each subject was scanned at four time points before and after BAL procedure. Image registration was performed to align images at different time points and different inflation levels. The resulting dense displacement fields were utilized to track tissue volume changes and reveal deformation patterns of local parenchymal tissue quantitatively. The registration accuracy was assessed by measuring landmark matching errors, which were on the order of 1 mm. The results show that quantitative-assessed fluid volume agreed well with bronchoscopist-reported unretrieved BAL volume in the whole lungs (squared linear correlation coefficient was 0.81). The average difference of lung tissue volume at baseline and after 24 hours was around 2%, which indicates that BAL fluid in the lungs was almost absorbed after 24 hours. Regional lung-function changes correlated with the presence of BAL fluid, and regional function returned to baseline as the fluid was reabsorbed