We present a review of the development of techniques available for the measurement of granular temperature in three dimensional dry granular flows, principally discussing positron emission particle tracking and magnetic resonance imaging. We will show how these techniques have given unique insight into granular behaviour, demonstrating phenomena such as buoyancy driven flows, non-equipartition and segregation, whilst also providing us with vital benchmark data for validating kinetic theory based models of rapid granular flow. (C) 2007 Elsevier B.V. All rights reserved.