Assessment of computed tomographic artefact in the pituitary fossa following needle implantation of radioactive rods

Computed tomographic scans of the pituitary fossa following treatment of pituitary tumours by interstitial irradiation were reviewed for the degree of metallic artefact created by the rods. Among 50 patients treated with 90 Y rods alone, none showed artefact to a degree that caused technically unsatisfactory images in coronal or axial cuts. Among the seven patients who had been treated with 198 Au, either alone (two patients) or with both 198 Au and 90 Y rods (five patients), six had severe artefact and in five of these the images were technically unsatisfactory in both coronal and axial slices. We conclude that following implantation of 90 Y rods, the currently preferred isotope, the pituitary fossa can be satisfactorily assessed by computed tomography.