The effects of target motion in kV-CBCT imaging

Sriram Padmanaban, Raghavendiran Boopathy, Bhuvana Kunjithapatham, Prabakar Sukumar, Vivekanandan Nagarajan

Research output: Contribution to journalArticlepeer-review


Background: To study the impact of target motion in kV-CBCT imaging. Material/Methods: To simulate the respiratory movement, dynamic phantom was programmed to move in three-dimension with a period of four seconds and of two different amplitudes (PA1 and PA2). The targets of well defined geometries (cylinder, sphere, solid triangle, U-shaped and dumbbell) were made using wax. The static targets were CT imaged (reference image). Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam. The line profiles along cranio-caudal direction, influence of target's initial moving phase and volume estimation using auto-contouring tool were used to analyze the effects of target motion on CBCT imaging. Results: Comparing the line profiles of targets in CBCT with CT, the length of average HU spread was reduced by 42.54±1.85%, except the cylindrical target which is by 19.35% for PA1. The percentage difference in reconstructed volume of static targets imaged using CBCT and CT (HU WW -500 to 0) ranges from -1.32% to -5.94%. The volume losses for targets imaged in dynamic mode PA1 ranges from 14.35% to 30.95% and for PA2 it was 21.29% to 43.80%. The solid triangle and cylindrical targets suffered the maximum and minimum volume losses respectively. Conclusions: Non-gated CBCT imaging of the moving targets encounters significant loss of volumetric information, due to scatter artifacts. These may result in a systematic error in re-contouring when CBCT images are used for the re-planning work.

Original languageEnglish (US)
Pages (from-to)61-66
Number of pages6
JournalPolish Journal of Radiology
Issue number1
StatePublished - 2010
Externally publishedYes


  • Re-contouring
  • Systematic error
  • Target motion

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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