Iranian Journal of Medical Physics

Iranian Journal of Medical Physics

Generating Synthetic Computed Tomography and Synthetic Magnetic Resonance (sMR: sT1w/sT2w) Images of the Brain Using Atlas-Based Method

Document Type : Original Paper

Authors
Fariba Farhadi Birgani 1
Mohamad Javad Tahmasebi Birgani 2
Roghayeh Kamran Samani 3
Fatemeh Maghsoodinia 4
1 Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
2 Radiation Therapy and Medical Physics Department, Golestan Hospital, Jundishapur University of Medical Sciences, Ahvaz, Iran
3 Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
4 Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
10.22038/ijmp.2018.32719.1399
Abstract
Introduction: Nowadays, magnetic resonance imaging (MRI) in combination with computed-tomography (CT) is increasingly being used in radiation therapy planning. MR and CT images are applied to determine the target volume and calculate dose distribution, respectively. Since the use of these two imaging modalities causes registration uncertainty and increases department workload and costs, in this study, brain synthetic CT (sCT) and synthetic MR (sMR: sT1w/sT2w) images were generated using Atlas-based method; consequently, just one type of image (CT or MR) is taken from the patient.
Material and Methods: The dataset included MR and CT paired images from 10 brain radiotherapy (RT) patients. To generate sCT/sMR images, first each MR/CT Atlas was registered to the MR/CT target image, the resulting transformation was applied to the corresponding CT/MR Atlas, which created the set of deformed images. Then, the deformed images were fused to generate a single sCT/sMR image, and finally, the sCT/sMR images were compared to the real CT/MR images using the mean absolute error (MAE).
Results: The results showed that the MAE of sMR (sT1w/sT2w) was less than that of sCT images. Moreover, sCT images based on T1w were in better agreement with real CT than sCT-based T2w. In addition, sT1w images represented a lower MAE relative to sT2w.
Conclusion: The CT target image was more successful in transferring the geometry of the brain tissues to the synthetic image than MR target.
Keywords
Computed Tomography Magnetic Resonance Imaging
Radiotherapy
Subjects

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Iranian Journal of Medical Physics
Volume 16, Issue 3 - Serial Number 3
May and June 2019
Pages 189-194

  • Receive Date 21 June 2018
  • Revise Date 12 September 2018
  • Accept Date 15 September 2018