EP-1506: Evaluation of cranial setup accuracy: a double shell positioning system versus an in-house 3-point mask solution. (April 2015) - Van der Meer, S.; Menten, N.; Verheesen, L.; Jager, J.J.; Zindler, J.D.; Eekers, D.B.P.; Bosmans, G.; Murrer, L.H.P.