Modulated electron radiotherapy (MERT) may potentially be an effective modality for the treatment of shallow tumors, but dose calculation accuracy and delivery efficiency challenges remain. The purpose of this work is to investigate the dose accuracy of MERT delivery using a photon multileaf collimator (pMLC) on a Siemens Primus accelerator. A Monte Carlo (MC)-based inverse treatment planning system was developed for the 3D treatment planning process. Phase space data of 6, 9, 12 and 15 MeV electron beams were commissioned and used as the input source for MC dose calculations. A treatment plan was performed based on the 3D CT data of a heterogeneous 'breast phantom' that mimics a breast cancer patient, and delivered with 22 segments, each associated with a particular energy and Monitor Unit value. Film and ion chamber dosimetry was carefully performed for the conversion from measurement reading to dose, and the results were employed for plan verification using the heterogeneous breast phantom and a solid water phantom. Dose comparisons between measurements and calculations showed agreement within 2% or 1 mm. We conclude that our in-house MC treatment planning system is capable of performing treatment planning and accurate dose calculations for MERT using the pMLC to deliver radiation therapy to the intact breast.

This paper analyzes the option coordination problem of a fresh agricultural product supply chain under two supply chain structures, when the production cost and the loss rate are disrupted simultaneously. This paper provides the explicit option coordination conditions for the disrupted supply chain under two supply chain structures, and then explores the effects of the disruptions and supply chain structure on the option coordination conditions. The results suggest that it is unfavorable to apply the original coordinating contracts without disruptions to coordinate the disrupted supply chain. The coordination of the disrupted supply chain can be achieved with knowledge of the distribution of demand. In two coordinating contracts for the disrupted supply chain, the exercise price is still at the original level without disruptions while the option price deviates from the original level without disruptions. Moreover, the relationships of the coordination conditions in two supply chain structures depend on the value of the profit allocation coefficient. When the profit allocation coefficient exceeds (falls behind) a certain threshold, the option price is set at a higher (lower) value in the supplier-led supply chain structure than in the distributor-led supply chain structure, while the exercise price is set at a lower (higher) value in the supplier-led supply chain structure than in the distributor-led supply chain structure. Finally, the disrupted supply chain with any supply chain structure will perform better in the modified coordinating contracts than in the original coordinating contracts without disruptions.

Purpose: This paper forms an e-commerce supply chain that include a manufacturer providing products and an online platform providing service. The reselling platform mode and the agent platform mode are considered through an exploration of the manufacturer Stackelberg (MS), vertical Nash (VN), platform Stackelberg (PS) power structures. The purpose of this paper is to explore the pricing and platform service decisions under different platform selling modes and channel power structures.Design/methodology/approach: Based on the game theory models, this paper investigates the interaction between the manufacturer and the online platform under four different scenarios. The optimal solutions of four models are provided. Through comparison analyses, this paper evaluates the impacts of platform selling mode and channel power structure on the pricing and platform service decisions and the members’ profits.Findings: The manufacturer prefers the MS power structure in any platform mode. The online platform prefers the PS (MS) power structure under a low (high) service cost efficiency in the reselling platform mode, while prefers the PS and VN power structures in the agent platform mode. Moreover, the manufacturer prefers the agent (reselling) platform mode under a low (high) service cost efficiency in any power structure. The online platform prefers the reselling platform mode in the MS and PS power structures, while prefers the reselling (agent) platform mode under a low (high) service cost efficiency in the VN power structures.Originality/value: The analysis result provides important managerial implications that help the supply chain members develop a better understanding of the selection of the platform selling mode and the effect of the channel power structure in the presence of platform service.

This paper builds the multi-period optimization models that incorporate put option contract and two supply chain structures to determine the production decision for a supplier and the ordering decision for a manufacturer in a two-stage supply chain. This paper applies the method of dynamic programming to derive the structures of optimal policies and provides an approximate algorithm to evaluate the myopic policies. This paper also conducts numerical examples to illustrate the impacts of put option contract, supply chain structure and demand risk on the members’ decisions and total profits as well as the channel’s total profit. The results indicate that put option contract can motivate to increase the channel’s service level and reduce the manufacturer’s inventory risk under two supply chain structures, when compared to the case without put option contract. In the manufacturer-led structure, the channel always benefits from put option contract, the supplier benefits from put option contract with a high option price and a low exercise price, while the manufacturer benefits from put option contract with a low option price and a high exercise price. In the supplier-led structure, the channel and the manufacturer always benefit from put option contract, while the supplier benefits from put option contract with a high option price and a low exercise price. With put option contract, the supplier is more profitable in the manufacturer-led structure than in the supplier-led structure, while the manufacturer and the channel are more profitable in the supplier-led structure than in the manufacturer-led structure. Without and with put option contract, the optimal total profits of two members and the channel will first decrease and then increase in the demand risk. Finally, this paper identifies the explicit conditions under which the multi-period supply chain can be coordinatedviaput option contract under two supply chain structures. With a coordinating contract, the supplier and the manufacturer are better off compared to the case without put option contract.

This study aims to explore how traceability affects quality and price competition in a duopoly. A theoretical model is developed in which both enterprises are liable to recall low-quality (defective) products identified by traceability and compensate consumers for the disutility caused by unidentified low-quality products. The equilibrium results are derived by determining the optimal product quality and sales price decisions. The key findings are highlighted below. (1) Traceability affects product quality primarily through the expected social cost (the sum of expected recall cost and expected consumer disutility), i.e., higher (lower) expected social cost induced by increased traceability of each enterprise leads to higher (lower) product quality for both enterprises, enhancing (reducing) quality competition. (2) If an enterprise’s improved (decreased) product quality is driven by its own increased traceability, it will result in lower (higher) consumer demand and profit, while it will result in higher (lower) consumer demand and profit if caused by its competitor’s increased traceability. (3) If an enterprise’s increased traceability results in higher expected social cost, the enterprise’s sales price falls while the competitor’s sales price rises; otherwise, both enterprises’ sales prices fall, leading to greater price competition. (4) Quality competition is unaffected by product liability but is improved by increased recall cost and consumer disutility, whereas price competition is intensified by increased consumer disutility but is reduced by increased product liability and recall cost. Managerial insights are also discussed.