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A Novel method to generate on-board 4D MRI using prior 4D MRI and on-board kV projections from a conventional LINAC for target localization in liver SBRT.

Publication ,  Journal Article
Harris, W; Wang, C; Yin, F-F; Cai, J; Ren, L
Published in: Med Phys
July 2018

PURPOSE: On-board MRI can provide superb soft tissue contrast for improving liver SBRT localization. However, the availability of on-board MRI in clinics is extremely limited. On the contrary, on-board kV imaging systems are widely available on radiotherapy machines, but its capability to localize tumors in soft tissue is limited due to its poor soft tissue contrast. This study aims to explore the feasibility of using an on-board kV imaging system and patient prior knowledge to generate on-board four-dimensional (4D)-MRI for target localization in liver SBRT. METHODS: Prior 4D MRI volumes were separated into end of expiration (EOE) phase (MRIprior ) and all other phases. MRIprior was used to generate a synthetic CT at EOE phase (sCTprior ). On-board 4D MRI at each respiratory phase was considered a deformation of MRIprior . The deformation field map (DFM) was estimated by matching DRRs of the deformed sCTprior to on-board kV projections using a motion modeling and free-form deformation optimization algorithm. The on-board 4D MRI method was evaluated using both XCAT simulation and real patient data. The accuracy of the estimated on-board 4D MRI was quantitatively evaluated using Volume Percent Difference (VPD), Volume Dice Coefficient (VDC), and Center of Mass Shift (COMS). Effects of scan angle and number of projections were also evaluated. RESULTS: In the XCAT study, VPD/VDC/COMS among all XCAT scenarios were 10.16 ± 1.31%/0.95 ± 0.01/0.88 ± 0.15 mm using orthogonal-view 30° scan angles with 102 projections. The on-board 4D MRI method was robust against the various scan angles and projection numbers evaluated. In the patient study, estimated on-board 4D MRI was generated successfully when compared to the "reference on-board 4D MRI" for the liver patient case. CONCLUSIONS: A method was developed to generate on-board 4D MRI using prior 4D MRI and on-board limited kV projections. Preliminary results demonstrated the potential for MRI-based image guidance for liver SBRT using only a kV imaging system on a conventional LINAC.

Duke Scholars

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

July 2018

Volume

45

Issue

7

Start / End Page

3238 / 3245

Location

United States

Related Subject Headings

  • Radiosurgery
  • Phantoms, Imaging
  • Particle Accelerators
  • Nuclear Medicine & Medical Imaging
  • Magnetic Resonance Imaging
  • Liver
  • Imaging, Three-Dimensional
  • Humans
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Harris, W., Wang, C., Yin, F.-F., Cai, J., & Ren, L. (2018). A Novel method to generate on-board 4D MRI using prior 4D MRI and on-board kV projections from a conventional LINAC for target localization in liver SBRT. Med Phys, 45(7), 3238–3245. https://doi.org/10.1002/mp.12998
Harris, Wendy, Chunhao Wang, Fang-Fang Yin, Jing Cai, and Lei Ren. “A Novel method to generate on-board 4D MRI using prior 4D MRI and on-board kV projections from a conventional LINAC for target localization in liver SBRT.Med Phys 45, no. 7 (July 2018): 3238–45. https://doi.org/10.1002/mp.12998.
Harris, Wendy, et al. “A Novel method to generate on-board 4D MRI using prior 4D MRI and on-board kV projections from a conventional LINAC for target localization in liver SBRT.Med Phys, vol. 45, no. 7, July 2018, pp. 3238–45. Pubmed, doi:10.1002/mp.12998.

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

July 2018

Volume

45

Issue

7

Start / End Page

3238 / 3245

Location

United States

Related Subject Headings

  • Radiosurgery
  • Phantoms, Imaging
  • Particle Accelerators
  • Nuclear Medicine & Medical Imaging
  • Magnetic Resonance Imaging
  • Liver
  • Imaging, Three-Dimensional
  • Humans
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering