Publications by authors named "C J Colyer"

Public health officials promoted COVID-19 vaccines to limit burdens placed on the U.S. healthcare system and end the pandemic.

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At the onset of the COVID-19 pandemic, government and medical guidelines emphasized social distancing to limit exposure. These guidelines significantly impacted closed religious communities, particularly those opposed to modern technologies, such as Amish and Mennonite communities. How did these religious communities respond to COVID-19 policies in the USA? We draw data from Ohio and Pennsylvania scribe entries published in an Amish/Mennonite correspondence newspaper.

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Purpose: To confirm the effectiveness of steel as a material for shielding photoneutrons produced in medical linear accelerators and report values for neutron first and second tenth value layer to be used as radiation protection quantities.

Methods: Monte Carlo code Geant4 was used to simulate transport of photoneutrons through primary barriers containing layers of concrete and steel. The photoneutron spectrum generated in high energy modern accelerator head components was simulated and projected to barriers of different thicknesses of steel including a control case of no barrier.

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This study evaluated the intrafractional auto-matching uncertainties of prostate-implanted fiducial markers when using the ExacTrac v6.5 (Brainlab, Feldkirchen, Germany) X-ray stereoscopic system. A customised phantom with 3 implanted gold seeds was initially positioned at the isocentre using a cone beam CT (CBCT) prior to intrafractional imaging.

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