Synthesis of CT images from digital body phantoms using CycleGAN

  • Tom RussEmail author
  • Stephan Goerttler
  • Alena-Kathrin Schnurr
  • Dominik F. Bauer
  • Sepideh Hatamikia
  • Lothar R. Schad
  • Frank G. Zöllner
  • Khanlian Chung
Original Article



The potential of medical image analysis with neural networks is limited by the restricted availability of extensive data sets. The incorporation of synthetic training data is one approach to bypass this shortcoming, as synthetic data offer accurate annotations and unlimited data size.


We evaluated eleven CycleGAN for the synthesis of computed tomography (CT) images based on XCAT body phantoms. The image quality was assessed in terms of anatomical accuracy and realistic noise properties. We performed two studies exploring various network and training configurations as well as a task-based adaption of the corresponding loss function.


The CycleGAN using the Res-Net architecture and three XCAT input slices achieved the best overall performance in the configuration study. In the task-based study, the anatomical accuracy of the generated synthetic CTs remained high (\(\mathrm{SSIM} = 0.64\) and \(\mathrm{FSIM} = 0.76\)). At the same time, the generated noise texture was close to real data with a noise power spectrum correlation coefficient of \(\mathrm{NCC} = 0.92\). Simultaneously, we observed an improvement in annotation accuracy of 65% when using the dedicated loss function. The feasibility of a combined training on both real and synthetic data was demonstrated in a blood vessel segmentation task (dice similarity coefficient \(\mathrm {DSC}=0.83\pm 0.05\)).


CT synthesis using CycleGAN is a feasible approach to generate realistic images from simulated XCAT phantoms. Synthetic CTs generated with a task-based loss function can be used in addition to real data to improve the performance of segmentation networks.


CT synthesis Generative adversarial networks CycleGAN Simulation-based deep learning Physical modeling 



We are thankful to Joshua Gawlitza and Leonard Chandra for their support regarding the CT data and the vessel segmentations.


This research project is part of the Research Campus M\(^2\)OLIE and funded by the German Federal Ministry of Education and Research (BMBF) within the Framework ’Forschungscampus - Public–Private Partnership for Innovation’ under the funding code 13GW0388A. We gratefully acknowledge the support of NVIDIA Corporation with the donation of the NVIDIA Titan Xp GPU used for this research.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© CARS 2019

Authors and Affiliations

  1. 1.Computer Assisted Clinical Medicine, Medical Faculty MannheimHeidelberg UniversityMannheimGermany
  2. 2.Austrian Center for Medical Innovation and TechnologyViennaAustria
  3. 3.Center for Medical Physics and Biomedical EngineeringMedical University ViennaViennaAustria

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