Physics and Imaging in Radiation Oncology Radiotherapy reference dose audit in the United Kingdom by the National Physical Laboratory: 20years of consistency and improvements  Russell A.S. Thomas, Matthew A. Bolt, Graham Bass, Rebecca Nutbrown, Tao Chen, Andrew Nisbet, Catharine H. Clark  Physics and Imaging in Radiation Oncology  Volume 3, Pages 21-27 (July 2017) DOI: 10.1016/j.phro.2017.07.005 Copyright © 2017 The Authors Terms and Conditions

Fig. 1 Measured beam output ratios separated into the eight individual regional audit groups. Mean value for each beam type in each group is indicated by a horizontal line (−). Physics and Imaging in Radiation Oncology 2017 3, 21-27DOI: (10.1016/j.phro.2017.07.005) Copyright © 2017 The Authors Terms and Conditions

Fig. 2 Plot of MV (a) and MeV (b) output results in order of completion. The standard deviation of the previous 20 audits (after removing three known erroneous MeV results) is shown by the dashed line. Bars indicate the standard uncertainty as given in the NPL report of the audit produced for the department. Physics and Imaging in Radiation Oncology 2017 3, 21-27DOI: (10.1016/j.phro.2017.07.005) Copyright © 2017 The Authors Terms and Conditions