RESUMEN
Objective To study the relationship between the dose indicator of computed radiography (CR) and the entrance surface dose (ESD),and to build a model for estimating ESD based on this relationship.Methods Taking Kodak CR system as the research object,a theoretical model for estimating the ESD was established according to theoretical derivations,and the key parameters in the model were determined through experiments in a CR system.Further experiments in another CR system were also conducted to verify the model.Results The ESDs were not only dependent on the dose indicator provided by the CR system,but also influenced by other factors,such as tube potential,patient's body thickness and energy response of the imaging plate.The estimation results of the model agreed well with the experiment results,and the relative deviation was confirmed within 20％.Conclusions The dose indicator based model can provide a relatively fast and easy way for evaluating the doses of patients undergoing X-ray diagnoses with the CR system.