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

Joseph E. Glaser, Na Song, Sridivya Jaini, Ruth Lorenzo, Charito Love

Research output: Contribution to journalArticlepeer-review


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 67Ga scan. Methods: A patient was referred for a whole-body 67Ga 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. Conclusion: 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.

Original languageEnglish (US)
Pages (from-to)278-280
Number of pages3
JournalJournal of Nuclear Medicine Technology
Issue number4
StatePublished - Dec 1 2012


  • Artifact
  • Electronic off-peak
  • Gallium
  • Gamma camera
  • Quality control
  • Scintigraphy

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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