A respiratory-guided 4D digital tomosynthesis

Dong Su Kim, Seungwan Lee, Tae Ho Kim, Seong Hee Kang, Kyeong Hyeon Kim, Dong Seok Shin, Siyong Kim, Tae Suk Suh

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The aim of this research was to introduce and evaluate a respiratory-guided slow gantry rotation 4D digital tomosynthesis (DTS). For each of ten volunteers, two breathing patterns were obtained for 3 min, one under free breathing conditions and the other with visual respiratory-guidance using an in-house developed respiratory monitoring system based on pressure sensing. Visual guidance was performed using a 4 s cycle sine wave with an amplitude corresponding to the average of end-inhalation peaks and end-exhalation valleys from the free-breathing pattern. The scan range was 40 degrees for each simulation, and the frame rate and gantry rotation speed were determined so that one projection per phase should be included. Both acquisition time and the number of total projections to be acquired (NPA) were calculated. Applying the obtained respiration pattern and the corresponding sequence, virtual projections were acquired under a typical geometry of Varian on-board imager for two virtual phantoms, modified Shepp-Logan (mSL) and extended cardiac-torso (XCAT). For the XCAT, two different orientations were considered, anterior-posterior (i.e. coronal) and left-right (i.e. sagittal). Projections were sorted to ten phases and image reconstruction was made using a modified filtered back-projection. Reconstructed images were compared with the planned breathing data (i.e. ideal situation) by structural similarity index (SSIM) and normalized root-mean-square error (NRMSE). For each case, simulation with guidance (SwG) showed motion-related artefact reduction compared to that under free-breathing (SuFB). SwG required less NPA but provided slightly higher SSIM and lower NRMSE values in all phantom images than SuFB did. In addition, the distribution of projections per phase was more regular in SwG. Through the proposed respiratory-guided 4D DTS, it is possible to reduce imaging dose while improving image quality.

Original languageEnglish
Article number245007
JournalPhysics in medicine and biology
Issue number24
StatePublished - Dec 10 2018


  • 4D DTS
  • 4D imaging
  • digital tomosynthesis
  • image guided radiation therapy
  • motion management
  • on-board imaging
  • respiratory guidance


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