Grids can significantly increase the contrast of diagnostic radiologic images, but they increase the dose to the patient and staff by a factor of two or more. Image quality with and without grids for fluoroscopic and photofluoro spot imaging of lower gastrointestinal studies has been examined. The authors show that dose reductions between one-third and one-half can be obtained with little or no degradation in contrast and diagnostic image quality if grids are not used for gastrointestinal examinations involving image intensifiers.