External radioactive markers for PET data-driven respiratory gating in positron emission tomography

  • Florian BütherEmail author
  • Iris Ernst
  • James Hamill
  • Hans T. Eich
  • Otmar Schober
  • Michael Schäfers
  • Klaus P. Schäfers
Original Article



Respiratory gating is an established approach to overcoming respiration-induced image artefacts in PET. Of special interest in this respect are raw PET data-driven gating methods which do not require additional hardware to acquire respiratory signals during the scan. However, these methods rely heavily on the quality of the acquired PET data (statistical properties, data contrast, etc.). We therefore combined external radioactive markers with data-driven respiratory gating in PET/CT. The feasibility and accuracy of this approach was studied for [18F]FDG PET/CT imaging in patients with malignant liver and lung lesions.


PET data from 30 patients with abdominal or thoracic [18F]FDG-positive lesions (primary tumours or metastases) were included in this prospective study. The patients underwent a 10-min list-mode PET scan with a single bed position following a standard clinical whole-body [18F]FDG PET/CT scan. During this scan, one to three radioactive point sources (either 22Na or 18F, 50–100 kBq) in a dedicated holder were attached the patient’s abdomen. The list mode data acquired were retrospectively analysed for respiratory signals using established data-driven gating approaches and additionally by tracking the motion of the point sources in sinogram space. Gated reconstructions were examined qualitatively, in terms of the amount of respiratory displacement and in respect of changes in local image intensity in the gated images.


The presence of the external markers did not affect whole-body PET/CT image quality. Tracking of the markers led to characteristic respiratory curves in all patients. Applying these curves for gated reconstructions resulted in images in which motion was well resolved. Quantitatively, the performance of the external marker-based approach was similar to that of the best intrinsic data-driven methods. Overall, the gain in measured tumour uptake from the nongated to the gated images indicating successful removal of respiratory motion was correlated with the magnitude of the respiratory displacement of the respective tumour lesion, but not with lesion size.


Respiratory information can be assessed from list-mode PET/CT through PET data-derived tracking of external radioactive markers. This information can be successfully applied to respiratory gating to reduce motion-related image blurring. In contrast to other previously described PET data-driven approaches, the external marker approach is independent of tumour uptake and thereby applicable even in patients with poor uptake and small tumours.


List-mode PET Respiratory motion Respiratory gating Data-driven gating 



The authors thank Ulrike Althof, Anette Langnickel, Yvonne Heurich, Ines Markötter and Katarzyna Quirós-Hoppe for excellent technical assistance, and Judson Jones and Charles Watson of Siemens Molecular Imaging (Knoxville, TN) for valuable ideas and discussions. This study was supported by the Deutsche Forschungsgemeinschaft (DFG), Sonderforschungsbereich 656 (Molecular Cardiovascular Imaging, SFB 656 projects B2 and B3) and a research grant to the European Institute for Molecular Imaging (EIMI) from Siemens Medical Solutions (Erlangen, Germany).


  1. 1.
    Jakoby BW, Bercier Y, Conti M, Casey ME, Bendriem B, Townsend DW. Physical and clinical performance of the mCT time-of-flight PET/CT scanner. Phys Med Biol. 2011;56:2375–89.PubMedCrossRefGoogle Scholar
  2. 2.
    Bettinardi V, Presotto L, Rapisarda E, Picchio M, Gianolli L, Gilardi MC. Physical performance of the new hybrid PET/CT Discovery-690. Med Phys. 2011;38:5394–411.PubMedCrossRefGoogle Scholar
  3. 3.
    Rapisarda E, Bettinardi V, Thielemans K, Gilardi MC. Image-based point spread function implementation in a fully 3D OSEM reconstruction algorithm for PET. Phys Med Biol. 2010;55:4131–51.PubMedCrossRefGoogle Scholar
  4. 4.
    Tong S, Alessio AM, Kinahan PE. Noise and signal properties in PSF-based fully 3D PET image reconstruction: an experimental evaluation. Phys Med Biol. 2010;55:1453–73.PubMedCrossRefGoogle Scholar
  5. 5.
    Liu C, Pierce 2nd LA, Alessio AM, Kinahan PE. The impact of respiratory motion on tumor quantification and delineation in static PET/CT imaging. Phys Med Biol. 2009;54:7345–62.Google Scholar
  6. 6.
    Lang N, Dawood M, Büther F, Schober O, Schäfers M, Schäfers K. Organ movement reduction in PET/CT using dual-gated list mode acquisition. Z Med Phys. 2006;16:93–100.PubMedGoogle Scholar
  7. 7.
    Nehmeh SA, Erdi YE, Ling CC, Rosenzweig KE, Squire OD, Braban LE, et al. Effect of respiratory gating on reducing lung motion artifacts in PET imaging of lung cancer. Med Phys. 2002;29:366–71.PubMedCrossRefGoogle Scholar
  8. 8.
    Dawood M, Büther F, Lang N, Schober O, Schäfers KP. Respiratory gating in positron emission tomography: a comparison of different gating schemes. Med Phys. 2007;34:3067–76.PubMedCrossRefGoogle Scholar
  9. 9.
    García Vicente AM, Soriano Castrejón AM, Talavera Rubio MP, León Martín AA, Palomar Muñoz AM, Pilkington Woll JP, et al. (18)F-FDG PET-CT respiratory gating in characterization of pulmonary lesions: approximation towards clinical indications. Ann Nucl Med. 2010;24:207–14.PubMedCrossRefGoogle Scholar
  10. 10.
    Klein GJ, Reutter BW, Ho MW, Reed JH, Huesman RH. Real-time system for respiratory-cardiac gating in positron tomography. IEEE Trans Nucl Sci. 1998;45:2139–43.CrossRefGoogle Scholar
  11. 11.
    Wells RG, Ruddy TD, DeKemp RA, DaSilva JN, Beanlands RS. Single-phase CT aligned to gated PET for respiratory motion correction in cardiac PET/CT. J Nucl Med. 2010;51:1182–90.PubMedCrossRefGoogle Scholar
  12. 12.
    Schleyer PJ, O’Doherty MJ, Barrington SF, Marsden PK. Retrospective data-driven respiratory gating for PET/CT. Phys Med Biol. 2009;54:1935–50.PubMedCrossRefGoogle Scholar
  13. 13.
    Schleyer PJ, O’Doherty MJ, Marsden PK. Extension of a data-driven gating technique to 3D, whole body PET studies. Phys Med Biol. 2011;56:3953–65.PubMedCrossRefGoogle Scholar
  14. 14.
    He J, O’Keefe GJ, Jones G, Saunder T, Gong SJ, Geso M, et al. Evaluation of geometrical sensitivity for respiratory motion gating by GATE and NCAT simulation. Conf Proc IEEE Eng Med Biol Soc. 2007;1:4165–8.Google Scholar
  15. 15.
    He J, O’Keefe GJ, Geso M. Motion image compensation based on dynamic data in PET acquisition. J Inform Comput Sci. 2010;7:885–91.Google Scholar
  16. 16.
    Kesner AL, Kuntner C. A new fast and fully automated software based algorithm for extracting respiratory signal from raw PET data and its comparison to other methods. Med Phys. 2010;37:5550–9.PubMedCrossRefGoogle Scholar
  17. 17.
    Thielemans K, Rathore S, Engbrant F, Razifar P. Device-less gating for PET/CT using PCA. Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) Proceedings. IEEE; 2011. p. 3904–10.Google Scholar
  18. 18.
    Büther F, Ernst I, Dawood M, Kraxner P, Schäfers M, Schober O, et al. Detection of respiratory tumour motion using intrinsic list mode-driven gating in positron emission tomography. Eur J Nucl Med Mol Imaging. 2010;37:2315–27.PubMedCrossRefGoogle Scholar
  19. 19.
    Nehmeh SA, Erdi YE, Rosenzweig KE, Schoder H, Larson SM, Squire OD, et al. Reduction of respiratory motion artifacts in PET imaging of lung cancer by respiratory correlated dynamic PET: methodology and comparison with respiratory gated PET. J Nucl Med. 2003;44:1644–8.Google Scholar
  20. 20.
    Watson CC. New, faster, image-based scatter correction for 3D PET. IEEE Trans Nucl Sci. 2000;47:1587–94.CrossRefGoogle Scholar
  21. 21.
    van Elmpt W, Hamill J, Jones J, De Ruysscher D, Lambin P, Ollers M. Optimal gating compared to 3D and 4D PET reconstruction for characterization of lung tumours. Eur J Nucl Med Mol Imaging. 2011;38:843–55.PubMedCrossRefGoogle Scholar
  22. 22.
    Liu C, Alessio A, Pierce L, Thielemans K, Wollenweber S, Ganin A, et al. Quiescent period respiratory gating for PET/CT. Med Phys. 2010;37:5037–43.PubMedCrossRefGoogle Scholar
  23. 23.
    Koch N, Liu HH, Starkschall G, Jacobson M, Forster K, Liao Z, et al. Evaluation of internal lung motion for respiratory-gated radiotherapy using MRI: part I – correlating internal lung motion with skin fiducial motion. Int J Radiat Oncol Biol Phys. 2004;60:1459–72.PubMedCrossRefGoogle Scholar
  24. 24.
    Benning M, Kösters T, Lamare F. Combined correction and reconstruction methods. In: Dawood M, Jiang X, Schäfers K, editors. Correction techniques in emission tomography. Boca Raton: CRC Press; 2012.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Florian Büther
    • 1
    Email author
  • Iris Ernst
    • 2
  • James Hamill
    • 3
  • Hans T. Eich
    • 2
  • Otmar Schober
    • 4
  • Michael Schäfers
    • 1
  • Klaus P. Schäfers
    • 1
  1. 1.European Institute for Molecular ImagingUniversity of MünsterMünsterGermany
  2. 2.Department of Radiotherapy and RadiooncologyUniversity of MünsterMünsterGermany
  3. 3.Siemens Molecular ImagingKnoxvilleUSA
  4. 4.Department of Nuclear MedicineUniversity of MünsterMünsterGermany

Personalised recommendations