OBJECTIVE: The purpose of this study was to assess the effect of a quality control program on reducing errors in the generation of 3D images. MATERIALS AND METHODS: The average monthly error rate in reports by six 3D technologists (0.5-11 years of experience) using standardized clinical protocols was observed over 3 months. A training intervention was initiated and aimed at eliminating the observed errors. During the 3-month training period followed by a 9-month posttraining period, error rates were remeasured. Error rates before and after training were compared. RESULTS: The error rate was 16.1% during the initial observation period and decreased to 7.2% during the posttraining period despite a 7.6% average monthly increase in examination volume. The mean overall error rates were 5.2% for technologists with more than 4 years of experience and 10.6% for less-experienced technologists (p<0.001). There was a much greater effect of training among inexperienced than among experienced technologists (p<0.001). The proportion of examinations with a turnaround time of 4 hours or less increased in the posttraining period (p<0.0001). CONCLUSION: Quality control does not negatively affect productivity. Performance monitoring and technologist mentoring are essential for quality assurance and result in considerable improvement.