Hi, You should save the restored image from FAST (or just apply the bias field multiplicatively), then register the restored image with your structural using the bias field, or a function of it, as a cost weighting function for your surface coil data. That is, the weighting function should be small in regions where the surface coil data was weak and near unity where the data is good. Also, depending on your field of view, you may need to do some rough pre-alignment with the translation-only schedule files. All the best, Mark On Wednesday, February 4, 2004, at 09:08 pm, SUBSCRIBE FSL Zhang, X wrote: > Hi: > I am using surface coil to collect functional data and having > trouble to register the function data to my structural image. > I got the "bias field" using fast. what should I do with it? Any > suggestion and successful experience? > > Xian