A quality health service, as defined by the World Health Organization, 'is one which organizes resources in the most effective way to meet the health needs of those most in need, for prevention and care, safely, without waste and within higher level requirements'. As health care standards improve globally, providing an optimal service that meets international standards and public expectations requires effective quality management. The process of quality improvement aims at defining, measuring and setting quality standards, and overcoming the associated challenges that include rising costs and skills shortages. The objective of this publication is to provide a framework for quality management systems (QMSs) to be implemented, managed and sustained holistically in nuclear medicine departments. It builds upon the IAEA's QUANUM programme, which has successfully been implemented in more than 80 countries worldwide.