The RBV correction introduced by Thomas et al  extends the GTM method and performs a voxel-wise correction of the entire image.
In a first step the standard GTM correction is performed, resulting in a synthetic image CGTM, which consist of the VOIs filled with the corrected average values.
In a second step a corrected image is calculated, which is not any more homogeneous within the VOIs, and which shows an image of the entire brain, not just the GM pixels. The calculation uses the formula
whereby the measured PET image CMeasured is multiplied by a correction term calculated from the GTM corrected image and the point-spread function.
Note that the pixelwise correction may be problematic for dynamic data with low signal/noise ratio.