1. A method for reconstructing a computed tomography (CT) image of a subject, the method comprising: with a computed tomography (CT) imaging system, acquiring medical imaging data representing the subject that has been irradiated with a dose of radiation and reconstructing a CT image of the subject from said medical imaging data; calculating a raw analytical map of noise in a reconstructed CT image, said raw analytical map having arbitrary scaling; transforming the raw analytical map to a scaled map of noise that matches a spatial noise distribution at a local level of the reconstructed CT image; and forming a noise-reduced reconstructed CT image with the use of a denoising method applied to the reconstructed CT image and said spatial noise distribution at a local level of the reconstructed CT image.