Diagnostic imaging systems (e.g. X-rays and ultrasound) play an important role in medicine. Owing to increasing workloads now carried by clinical radiologists, the interpretation of medical images is increasingly being passed to radiographers. This is especially so in those areas of diagnoses where examinations are performed on large numbers of patients but when the frequency of the disorder is very low (e.g. mass mammography screening). This study explored the accuracy of the radiographic interpretation of pulmonary nodules by clinical radiologists and student radiographers, and their correlations with tests of field-dependency, visual search and spatial reasoning. Overall performance in lung nodule detection gave a mean ROC (Az)=0.851 for student radiographers, while radiologists achieved 0.871. No correlation was found between diagnostic performance and either field-dependency or visual search. A significant negative correlation was found between diagnostic performance and spatial reasoning (p < 0.05).