The impact of a 1.5 T MRI linac fringe field on neighbouring linear accelerators  Thijs Perik, Jochem Kaas, Frits Wittkämper  Physics and Imaging in Radiation Oncology  Volume 4, Pages 12-16 (October 2017) DOI: 10.1016/j.phro.2017.10.002 Copyright © 2017 The Authors Terms and Conditions

Fig. 1 Layout of the treatment rooms. The MR-Linac is installed in the upper left corner and surrounded by 3 standard linear accelerators, A, B and C at distances of respectively, 7.5, 5.5 and 11 m. The displayed Gauss lines are 0.5 G (Outer) and 2 G (Inner), and are taken from the vendor specifications. Physics and Imaging in Radiation Oncology 2017 4, 12-16DOI: (10.1016/j.phro.2017.10.002) Copyright © 2017 The Authors Terms and Conditions

Fig. 2 Relative flatness ratio to 0°, for 2 directions (Left-Right (AB) and Gun-Target (GT)) and 2 arcs (clockwise and counter clockwise) for Linac A 6 MV. Before the ramp-up to 1.5 T (a), directly after the ramp-up without corrections to the Look-Up tables (b), and after correction of the LUT (c). Physics and Imaging in Radiation Oncology 2017 4, 12-16DOI: (10.1016/j.phro.2017.10.002) Copyright © 2017 The Authors Terms and Conditions

Fig. 3 Difference in integral symmetry to 0°, for 2 directions (Left-Right (AB) and Gun-Target (GT)) and 2 arcs (clockwise and counter clockwise) for Linac A 6 MV. Before the ramp-up to 1.5 T (a), directly after the ramp-up without corrections to the Look-Up tables (b), and after correction of the LUT (c). Physics and Imaging in Radiation Oncology 2017 4, 12-16DOI: (10.1016/j.phro.2017.10.002) Copyright © 2017 The Authors Terms and Conditions

Fig. 4 Difference in integral symmetry to 0°, for 2 directions (Left-Right (AB) and Gun-Target (GT)) and 2 arcs (clockwise and counter clockwise) for Linac A 6 MV. Before the ramp-down from 1.5 T (a), directly after the ramp-down with the original Look-Up tables (b), and after correction of the LUT (c). Physics and Imaging in Radiation Oncology 2017 4, 12-16DOI: (10.1016/j.phro.2017.10.002) Copyright © 2017 The Authors Terms and Conditions

Fig. 5 Difference in integral symmetry to 0°, for 2 directions (Left-Right (AB) and Gun-Target (GT)) and 2 arcs (clockwise and counter clockwise) for Linac A 6 MV. Before the scheduled ramp-down (a) and after the 2nd ramp-up using the same LUT values as before the ramp-down (b). Physics and Imaging in Radiation Oncology 2017 4, 12-16DOI: (10.1016/j.phro.2017.10.002) Copyright © 2017 The Authors Terms and Conditions