title: Photomultiplier tube artifacts on 67Ga-citrate imaging caused by loss of correction floods due to an off-peak status of one head of a dual-head γ-camera.
abstract: γ-cameras use flood-field corrections to ensure image uniformity during clinical imaging. A loss or corruption of the correction data of one head of a dual-head camera can result in an off-peak artifactual appearance. We present our experience with the occurrence of such an incident on a (67)Ga scan.
  
  
  METHODS
  A patient was referred for a whole-body (67)Ga scan to evaluate for causes of neutropenic fever. Whole-body planar and static images of the head, chest, abdomen, pelvis, and lower extremities in multiple projections were obtained.
  
  
  RESULTS
  Whole-body images showed decreased image quality on the anterior view obtained with detector 1 and an unremarkable posterior image obtained with detector 2. A problem with detector 2 was suspected, and additional static images were obtained after rotation of the detector heads. The posterior images taken with detector 1 showed photomultiplier tube outlines. The anterior images taken with detector 2 showed improved count and image quality. It was later found that the uniformity map for detector 2 had been lost and that this software malfunction led to the resulting imaging problem.
  
  
  CONCLUSIONS
  When artifacts with an off-peak appearance are seen on scintigraphic images, evaluation of possible causes should include not only isotope window settings but also an incorrect or corrupted uniformity map.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Montefiore Medical Center, Bronx, NY, USA. joseph-glaser@gmail.com
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Glaser
authors.forename: Na
authors.initials: N
authors.lastname: Song
authors.forename: Sridivya
authors.initials: S
authors.lastname: Jaini
authors.forename: Ruth
authors.initials: R
authors.lastname: Lorenzo
authors.forename: Charito
authors.initials: C
authors.lastname: Love
mesh_terms: D016477:Artifacts; D002951:Citrates; D005334:Fever / Q000150:complications; D005708:Gallium; D015902:Gamma Cameras; D006801:Humans; D008297:Male; D008875:Middle Aged; D009503:Neutropenia / Q000150:complications / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D012399:Rotation; D051598:Whole Body Imaging / Q000295:instrumentation*
chemical_list: D002951:Citrates; D005708:Gallium; C103850:gallium citrate