Fig. 3
From: Practical issues and limitations of brain attenuation correction on a simultaneous PET-MR scanner
a Pad located under the patient’s head in the head coil. b A triangular pad (used in pairs) that is positioned between the coil and the head. c The same triangular pad compressed with tape to mimic compression when in use. d Transverse and e coronal CT images in HU showing the location of the pads for phantom assessment (CFOV = centre of the field of view). The blue arrows in d and e highlight the location of the pads in the CT images