Phase-specific cone beam computed tomography reduces reconstructed volume loss of moving phantom

H. L. Chao, W. L. Chen, C. C. Hu, J. K. Wu, C. J. Wu, J. C.H. Cheng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Purpose: The accurate volumetric calculation of moving targets/organs is required to use cone-beam computed tomography (CBCT) for replanning purposes. This study was aimed to correct the reconstructed volume losses of moving phantoms by phase-specific CBCT. Materials and methods: Planning fan-beam CT (FBCT) of five hepatobiliary/gastrointestinal/pancreatic cancer patients were acquired under active breathing control and compared with free-breathing CBCT for kidney volumes. Three different-sized ball phantoms were scanned by FBCT and CBCT. Images were imported to a planning system to compare the reconstructed volumes. The phantoms were moved longitudinally on an oscillator with different amplitudes/frequencies. The phase-specific projections of CBCT for moving phantoms were selected for volume reconstruction. Results: The differences in reconstructed volumes of static small, medium, large phantoms between FBCT and CBCT were -∈6.7%, -∈2.3%, and -∈2.0%, respectively. With amplitudes of 7.5-20 mm and frequencies of 8-16 oscillations/min, volume losses on CBCT were comparable with FBCT in large moving phantoms (range 9.1-27.2%). Amplitudes were more subject to volume losses than frequencies. On phase-specific CBCT, volume losses were reduced to 2.3-6.5% by reconstruction using 2-3 projections at end/midoscillation phase. Conclusion: Amplitude had more impact than frequency on volume losses of moving phantoms on CBCT. Phase-specific CBCT reduced volume losses.

Original languageEnglish
Pages (from-to)77-83
Number of pages7
JournalStrahlentherapie und Onkologie
Issue number1
Publication statusPublished - 2012 Jan


  • Cone-beam computed tomography
  • Fan-beam computed tomography
  • Motion
  • Phase
  • Volume

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Oncology


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