Pengpeng Zhang

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PURPOSE The Varian RapidArc is a system for intensity-modulated radiotherapy (IMRT) treatment planning and delivery. RapidArc incorporates capabilities such as variable dose-rate, variable gantry speed, and accurate and fast dynamic multileaf collimators (DMLC), to optimize dose conformality, delivery efficiency, accuracy and reliability. We developed(More)
PURPOSE To develop an optimization method using volumetric modulated arc therapy (VMAT) and evaluate VMAT plans relative to the standard intensity-modulated radiotherapy (IMRT) approach in prostate cancer. METHODS AND MATERIALS A single gantry rotation was modeled using 177 equispaced beams. Multileaf collimator apertures and dose rates were optimized(More)
PURPOSE To assess the effect of metformin intake on cancer incidence and mortality. METHODS Original articles in English published until June 15, 2012 were searched for in electronic databases (MEDLINE, ISI Web of Science and EMBASE databases) and relevant reviews were examined. Meta-analysis was applied to calculate the summary relative risk (SRR) and(More)
PURPOSE To design and optimize trajectory-based, noncoplanar subarcs for volumetric modulated arc therapy (VMAT) deliverable on both Varian TrueBEAM system and traditional accelerators; and to investigate their potential advantages for treating central nervous system (CNS) tumors. METHODS AND MATERIALS To guide the computerized selection of beam(More)
Dear Editor, We retrospectively analyzed the microbiological spectrum and evaluated the factors associated with infection-related mortality in renal recipients with acute respiratory distress syndrome (ARDS) within 6 months after transplantation, according to the Berlin definition of ARDS [1], over the 10-year period from 2004 to 2014. Patient demographic(More)
PURPOSE To investigate the use of advanced ultrasonic imaging to quantitatively evaluate normal-tissue toxicity in breast-cancer radiation treatment. METHODS AND MATERIALS Eighteen breast cancer patients who received radiation treatment were enrolled in an institutional review board-approved clinical study. Radiotherapy involved a radiation dose of 50.0(More)
PURPOSE The purpose of this study is to investigate how the spatial relationship between the isocenters of the first and second radiosurgeries affects the overall outcome. METHODS AND MATERIALS We performed a retrospective study on 40 patients who had repeat gamma knife radiosurgery for trigeminal neuralgia. Only one 4-mm isocenter was applied in both(More)
Silicon nanomembranes (SiNMs) are very thin, large, free-standing or free-floating two-dimensional (2D) single crystals that can variously be flat, rolled into tubes, or made into any number of odd shapes, cut into millions of identical wires, used as conformal sheets, or chopped into tiny pieces. Because SiNMs are mostly surface or interface and little(More)
The goal of this study was to implement and validate a noninvasive, quantitative ultrasonic technique for accurate and reproducible measurement of normal-tissue toxicity in radiation therapy. The authors adapted an existing ultrasonic tissue characterization (UTC) technique that used a calibrated 1D spectrum based on region-of-interest analysis. They(More)
The widely used 'silicon-on-insulator' (SOI) system consists of a layer of single-crystalline silicon supported on a silicon dioxide substrate. When this silicon layer (the template layer) is very thin, the assumption that an effectively infinite number of atoms contributes to its physical properties no longer applies, and new electronic, mechanical and(More)