The use of instruments to measure health-related quality of life has become commonplace in medical research, although their use is still unusual in the evaluation of diagnostic technologies. Dr Greenfield has pointed out the potential to abuse as well as use these methods. The cautions that Dr Greenfield has outlined apply to any such research, whether one is evaluating a new drug or a new imaging device. Even though the chain of events from diagnostic technology to patient outcome is longer than for therapeutic interventions, we maintain that quality-of-life instruments are potentially valuable tools for evaluating any of the links in this chain.