Development of a 4D phantom for respiratory motion modeling during Cone-Beam CT (CBCT) imaging on the Varian On-Board Imager (OBI)

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Cone-beam computed tomography (CBCT) imaging is widely used in image guided radiotherapy. Current protocols assume the patient to be static during imaging but, respiratory motion can affect the reconstructed CBCT images. The objective of this study is to simulate respiratory motion effects on a CBCT image using a digital phantom constructed from actual 4D Magnetic Resonance Imaging (MRI) data. Firstly, the length of the 4D MR data was extended to 1-minute, mimicking a typical CBCT imaging acquisition period over a 360-degree scan. The MR images are then segmented and converted to CT attenuation values. The Varian On-Board Imager geometry was used in the simulation where Poisson noise was added to realistically model imaging noise. Simulated projections were reconstructed using the standard Feldkamp-Davis-Kress algorithm. The images were then compared against the developed phantom at two respiratory positions: end-inspiration, and end-expiration, using normalized root mean squared error (NRMSE) and difference images. The results were encouraging with a NRMSE increment of 0.59% when noise was added into the phantom, whilst a −0.51% decrease when an additional Hann filter was used during reconstruction. The respiratory motion effects were successfully modeled when the results showed a 0.55\% difference between the different positions. This is also observed from the difference images by selecting a region-of-interest with NRMSE values evaluated as 33.84% and 51.26% respectively, constituting a significant 17.42% difference. Therefore, it is evident that respiratory motion affects image reconstruction quality. This indicates the currently practiced protocol and reconstruction algorithm must consider respiratory motion to ensure accuracy.

Original languageEnglish
Title of host publication2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages451-456
Number of pages6
ISBN (Electronic)9781538624715
DOIs
Publication statusPublished - 24 Jan 2019
Event2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Kuching, Malaysia
Duration: 3 Dec 20186 Dec 2018

Publication series

Name2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings

Conference

Conference2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018
CountryMalaysia
CityKuching
Period3/12/186/12/18

Fingerprint

Image sensors
Cone-Beam Computed Tomography
Cones
cones
Imaging techniques
Noise
Image-Guided Radiotherapy
Radiotherapy
Image reconstruction
Computer-Assisted Image Processing
Tomography
expiration
inspiration
image reconstruction
Magnetic Resonance Imaging
Geometry
magnetic resonance
radiation therapy
acquisition
tomography

Keywords

  • Cone-beam CT
  • Digital phantom
  • Image reconstruction
  • Respiratory motion

ASJC Scopus subject areas

  • Biomedical Engineering
  • Medicine (miscellaneous)
  • Health Informatics
  • Instrumentation

Cite this

Mohd Amin, A. T., Mokri, S. S., Ahmad, R., & Abd Rahni, A. A. (2019). Development of a 4D phantom for respiratory motion modeling during Cone-Beam CT (CBCT) imaging on the Varian On-Board Imager (OBI). In 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings (pp. 451-456). [8626653] (2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/IECBES.2018.8626653

Development of a 4D phantom for respiratory motion modeling during Cone-Beam CT (CBCT) imaging on the Varian On-Board Imager (OBI). / Mohd Amin, Adam Tan; Mokri, Siti Salasiah; Ahmad, Rozilawati; Abd Rahni, Ashrani Aizzuddin.

2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings. Institute of Electrical and Electronics Engineers Inc., 2019. p. 451-456 8626653 (2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Mohd Amin, AT, Mokri, SS, Ahmad, R & Abd Rahni, AA 2019, Development of a 4D phantom for respiratory motion modeling during Cone-Beam CT (CBCT) imaging on the Varian On-Board Imager (OBI). in 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings., 8626653, 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings, Institute of Electrical and Electronics Engineers Inc., pp. 451-456, 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018, Kuching, Malaysia, 3/12/18. https://doi.org/10.1109/IECBES.2018.8626653
Mohd Amin AT, Mokri SS, Ahmad R, Abd Rahni AA. Development of a 4D phantom for respiratory motion modeling during Cone-Beam CT (CBCT) imaging on the Varian On-Board Imager (OBI). In 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings. Institute of Electrical and Electronics Engineers Inc. 2019. p. 451-456. 8626653. (2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings). https://doi.org/10.1109/IECBES.2018.8626653
Mohd Amin, Adam Tan ; Mokri, Siti Salasiah ; Ahmad, Rozilawati ; Abd Rahni, Ashrani Aizzuddin. / Development of a 4D phantom for respiratory motion modeling during Cone-Beam CT (CBCT) imaging on the Varian On-Board Imager (OBI). 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings. Institute of Electrical and Electronics Engineers Inc., 2019. pp. 451-456 (2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018 - Proceedings).
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abstract = "Cone-beam computed tomography (CBCT) imaging is widely used in image guided radiotherapy. Current protocols assume the patient to be static during imaging but, respiratory motion can affect the reconstructed CBCT images. The objective of this study is to simulate respiratory motion effects on a CBCT image using a digital phantom constructed from actual 4D Magnetic Resonance Imaging (MRI) data. Firstly, the length of the 4D MR data was extended to 1-minute, mimicking a typical CBCT imaging acquisition period over a 360-degree scan. The MR images are then segmented and converted to CT attenuation values. The Varian On-Board Imager geometry was used in the simulation where Poisson noise was added to realistically model imaging noise. Simulated projections were reconstructed using the standard Feldkamp-Davis-Kress algorithm. The images were then compared against the developed phantom at two respiratory positions: end-inspiration, and end-expiration, using normalized root mean squared error (NRMSE) and difference images. The results were encouraging with a NRMSE increment of 0.59{\%} when noise was added into the phantom, whilst a −0.51{\%} decrease when an additional Hann filter was used during reconstruction. The respiratory motion effects were successfully modeled when the results showed a 0.55\{\%} difference between the different positions. This is also observed from the difference images by selecting a region-of-interest with NRMSE values evaluated as 33.84{\%} and 51.26{\%} respectively, constituting a significant 17.42{\%} difference. Therefore, it is evident that respiratory motion affects image reconstruction quality. This indicates the currently practiced protocol and reconstruction algorithm must consider respiratory motion to ensure accuracy.",
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