As technologies emerge that have the potential to significantly improve the detection and recognition of concealed weapons and objects on personnel, the ultimate effectiveness of these systems is still reliant on the performance of the operator of that system. This paper will report the work undertaken to evaluate and optimise the effectiveness of a millimetre wave (MMW) system. This was achieved through an extensive series of trials carried out at a large UK airport and also under more controlled field conditions. The paper will discuss the work carried out to develop a simple and usable human-computer interface, and the development and implementation of the training program. This training program was based on a detailed task analysis, leading to the identification of competencies required for effective weapon detection and recognition. Ultimately, however, the effectiveness of emerging technologies, such as the MMW, needs to be empirically demonstrated. To that end we will report the results of comprehensive psychophysical performance assessments that has led, probably for the first time, to performance metrics for a MMW system that combine the performance of the system with the performance of the user. For emerging technologies to be truly successful a collaborative and co-operative approach from technologists, regulators, airport authorities, human factors specialists and occupational psychologists is required. The work reported will emphasise the importance of the collaboration that has occurred.