Methods and systems for modulating radiation dose

A method and system for determining a dose of modulation (DOM) profile are provided. The method may include obtaining a 3D image and a topogram image of the object. The method may further include obtaining a dose of modulation (DOM) profile generation model. The DOM profile generation model may be generated by training a preliminary model based on a plurality of sample CT images, a plurality of sample 3D images corresponding to the plurality of sample CT images, respectively, and a plurality of sample topogram images corresponding to the plurality of sample CT images, respectively. The method may further include executing the DOM profile generation model to generate a DOM profile related to a computed tomography (CT) scan of the object based on the 3D image and the topogram image of the object.