1. A method for producing an image of a subject positioned in a field of view (FOV) of a medical imaging system, the steps comprising: a) acquiring, with the medical imaging system, a plurality of image data sets of the subject positioned in the FOV at a corresponding plurality of time frames; b) reconstructing a sparsifying image by combining the data from the plurality of acquired image data sets; c) producing a sparsifying image data set by transforming the sparsifying image reconstructed in step b); d) producing a difference image data set by subtracting the image data set acquired in a selected time frame from the sparsifying image data set produced in step d); e) iteratively reconstructing a correction image using the difference image data set produced in step d); and f) subtracting the correction image from the sparsifying image reconstructed in step b) to produce the image of the subject at the selected time frame.