Aim: To characterize the main reasons for requesting lumbar spine computed tomography (CT) scans at primary care units wi-thin a Local Health Unit (ULS), and to intervene in order to improve the quality of such requests. Type of study: Quasi-experimental, pre- post assessment. Local: Six Functional Units (UF) of ULS. Population: Forty-nine family physicians. Methods: All the lumbar spine CT scans performed betw...