780 research outputs found
How extensive of a 4D dataset is needed to estimate cumulative dose distribution plan evaluation metrics in conformal lung therapy?a)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134757/1/mp0624.pd
Technical note: Creating a four‐dimensional model of the liver using finite element analysis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134997/1/mp5055.pd
Calcium isotopes in enamel of modern and Plio-Pleistocene East African mammals
Calcium isotope analyses show a depletion of heavy calcium isotopes in vertebrates, compared to food sources along each trophic step. Recent studies show considerable variability of the calcium isotopic composition of bone and teeth in modern mammals, leading to inconclusive interpretations regarding the utility of Ca isotopes for trophic inference in mammal-dominated terrestrial ecosystems. Here, we analyzed modern enamel samples from the Tsavo National Park (Kenya), and fossil enamel samples dated from ca. 4 Ma to 1.6 Ma from the Turkana Basin (Kenya). We found a constancy of taxa ordering between the modern and fossil datasets, suggesting that the diagenesis of calcium isotopes is minimal in fossils. In modern herbivore samples using similar digestive physiologies, browsers are enriched in Ca-44 compared to grazers. Both grazer and browser herbivore tooth enamel is enriched in Ca-44 relative to carnivores by about +0.30 parts per thousand. Used together, carbon and calcium isotope compositions may help refine the structure of the C-3 and C-4 trophic chains in the fossil record. Due to their high preservation potential, combining both carbon and calcium isotope systems represent a reliable approach to the reconstruction of the structure of past ecosystems. (C) 2018 Eisevier B.V. All rights reserved
A fluence convolution method to account for respiratory motion in three‐dimensional dose calculations of the liver: A Monte Carlo study
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134815/1/mp1412.pd
Report of IRPA task group on the impact of the eye lens dose limits
In 2012 IRPA established a task group (TG) to identify key issues in the implementation of the revised eye lens dose limit. The TG reported its conclusions in 2013. In January 2015, IRPA asked the TG to review progress with the implementation of the recommendations from the early report and to collate current practitioner experience. This report presents the results of a survey on the view of the IRPA professionals on the new limit to the lens of the eye and on the wider issue of tissue reactions. Recommendations derived from the survey are presented. This report was approved by IRPA Executive Council on 31 January 2017
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