Abdominal organ motion measured using 4D CT

Edward D. Brandner, Andrew Wu, Hungcheng Chen, Dwight Heron, Shalom Kalnicki, Krishna Komanduri, Kristina Gerszten, Steve Burton, Irfan Ahmed, Zhenyu Shou

Research output: Contribution to journalArticlepeer-review

146 Scopus citations


Purpose: To measure respiration-induced abdominal organ motion using four-dimensional computed tomography (4D CT) scanning and to examine the organ paths. Methods and Materials: During 4D CT scanning, consecutive CT images are acquired of the patient at each couch position. Simultaneously, the patient's respiratory pattern is recorded using an external marker block taped to the patient's abdomen. This pattern is used to retrospectively organize the CT images into multiple three-dimensional images, each representing one breathing phase. These images are analyzed to measure organ motion between each phase. The displacement from end expiration is compared to a displacement limit that represents acceptable dosimetric results (5 mm). Results: The organs measured in 13 patients were the liver, spleen, and left and right kidneys. Their average superior to inferior absolute displacements were 1.3 cm for the liver, 1.3 cm for the spleen, 1.1 cm for the left kidney, and 1.3 cm for the right kidney. Although the organ paths varied among patients, 5 mm of superior to inferior displacement from end expiration resulted in less than 5 mm of displacement in the other directions for 41 of 43 organs measured. Conclusions: Four-dimensional CT scanning can accurately measure abdominal organ motion throughout respiration. This information may result in greater organ sparing and planning target volume coverage.

Original languageEnglish (US)
Pages (from-to)554-560
Number of pages7
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number2
StatePublished - Jun 1 2006


  • 4D CT
  • Organ motion
  • Radiation therapy
  • Radiation treatment planning
  • Respiration

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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