Optimization of a shorter variable-acquisition time for legs to achieve true whole-body PET/CT images

  • Takuro Umeda
  • Kenta MiwaEmail author
  • Taisuke Murata
  • Noriaki Miyaji
  • Kei Wagatsuma
  • Kazuki Motegi
  • Takashi Terauchi
  • Mitsuru Koizumi
Scientific Paper


The present study aimed to qualitatively and quantitatively evaluate PET images as a function of acquisition time for various leg sizes, and to optimize a shorter variable-acquisition time protocol for legs to achieve better qualitative and quantitative accuracy of true whole-body PET/CT images. The diameters of legs to be modeled as phantoms were defined based on data derived from 53 patients. This study analyzed PET images of a NEMA phantom and three plastic bottle phantoms (diameter, 5.68, 8.54 and 10.7 cm) that simulated the human body and legs, respectively. The phantoms comprised two spheres (diameters, 10 and 17 mm) containing fluorine-18 fluorodeoxyglucose solution with sphere-to-background ratios of 4 at a background radioactivity level of 2.65 kBq/mL. All PET data were reconstructed with acquisition times ranging from 10 to 180, and 1200 s. We visually evaluated image quality and determined the coefficient of variance (CV) of the background, contrast and the quantitative %error of the hot spheres, and then determined two shorter variable-acquisition protocols for legs. Lesion detectability and quantitative accuracy determined based on maximum standardized uptake values (SUVmax) in PET images of a patient using the proposed protocols were also evaluated. A larger phantom and a shorter acquisition time resulted in increased background noise on images and decreased the contrast in hot spheres. A visual score of ≥ 1.5 was obtained when the acquisition time was ≥ 30 s for three leg phantoms, and ≥ 120 s for the NEMA phantom. The quantitative %errors of the 10- and 17-mm spheres in the leg phantoms were ± 15 and ± 10%, respectively, in PET images with a high CV (scan < 30 s). The mean SUVmax of three lesions using the current fixed-acquisition and two proposed variable-acquisition time protocols in the clinical study were 3.1, 3.1 and 3.2, respectively, which did not significantly differ. Leg acquisition time per bed position of even 30–90 s allows axial equalization, uniform image noise and a maximum ± 15% quantitative accuracy for the smallest lesion. The overall acquisition time was reduced by 23–42% using the proposed shorter variable than the current fixed-acquisition time for imaging legs, indicating that this is a useful and practical protocol for routine qualitative and quantitative PET/CT assessment in the clinical setting.


True whole-body PET/CT FDG Variable-time acquisition Leg Acquisition protocol 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Beyer T, Townsend DW, Brun T, Kinahan PE, Charron M, Roddy R et al (2000) A combined PET/CT scanner for clinical oncology. J Nucl Med 41:1369–1379PubMedGoogle Scholar
  2. 2.
    Sahiner I, Vural GU (2014) Positron emission tomography/computerized tomography in lung cancer. Quant Imaging Med Surg 4:195–206PubMedPubMedCentralGoogle Scholar
  3. 3.
    Kawata S, Imaizumi M, Kako Y, Oku N (2014) Clinical impact of “true whole-body” (18)F-FDG PET/CT: lesion frequency and added benefit in distal lower extremities. Ann Nucl Med 28:322–328CrossRefPubMedGoogle Scholar
  4. 4.
    Boellaard R, Delgado-Bolton R, Oyen WJ, Giammarile F, Tatsch K, Eschner W et al (2015) FDG PET/CT: EANM procedure guidelines for tumour imaging: version 2.0. Eur J Nucl Med Mol Imaging 42:328–354CrossRefPubMedGoogle Scholar
  5. 5.
    Von Schulthess GK, Steinert HC, Hany TF (2006) Integrated PET/CT: current applications and future directions. Radiology 238:405–422CrossRefGoogle Scholar
  6. 6.
    Delbeke D, Coleman RE, Guiberteau MJ, Brown ML, Royal HD, Siegel BA et al (2006) Procedure guideline for tumor imaging with 18F-FDG PET/CT 1.0. J Nucl Med 47:885–895PubMedGoogle Scholar
  7. 7.
    Sebro R, Mari-Aparici C, Hernandez-Pampaloni M (2013) Value of true whole-body FDG-PET/CT scanning protocol in oncology: optimization of its use based on primary diagnosis. Acta Radiol 54(5):534–539CrossRefPubMedGoogle Scholar
  8. 8.
    Koyama M, Koizumi M (2014) FDG-PET images of acrometastases. Clin Nucl Med 39:298–300CrossRefPubMedGoogle Scholar
  9. 9.
    Osman MM, Chaar BT, Muzaffar R, Oliver D, Reimers HJ, Walz B et al (2010) 18F-FDG PET/CT of patients with cancer: comparison of whole-body and limited whole-body technique. AJR Am J Roentgenol 195:1397–1403CrossRefPubMedGoogle Scholar
  10. 10.
    Krizsan AK, Czernin J, Balkay L, Dahlbom M (2014) Whole body PET imaging using variable acquisition times. IEEE Trans Nucl Sci 61(1):115–120CrossRefGoogle Scholar
  11. 11.
    Miwa K, Umeda T, Murata T, Wagatsuma K, Miyaji N, Terauchi T et al (2016) Evaluation of scatter limitation correction: a new method of correcting photopenic artifacts caused by patient motion during whole-body PET/CT imaging. Nucl Med Commun 37(2):147–154CrossRefPubMedGoogle Scholar
  12. 12.
    Carlier T, Ferrer L, Necib H, Bodet-Milin C, Rousseau C, Kraeber-Bodéré F (2014) Clinical NECR in 18F-FDG PET scans: optimization of injected activity and variable acquisition time. Relationship with SNR. Phys Med Biol 59:6417–6430CrossRefPubMedGoogle Scholar
  13. 13.
    Wilson JM, Coleman RE, Turkington TG (2011) Variable-time positron emission tomography leg protocol to equalize noise for positron emission tomography/computed tomography acquisitions. Nucl Med Commun 32:868–872CrossRefPubMedGoogle Scholar
  14. 14.
    Wagatsuma K, Miwa K, Miyaji N, Murata T, Umeda T, Osawa A et al (2014) Comparison of (18)F-fluoro-2-deoxy-D-glucose positron emission tomography /computed tomography image quality between commercial and in-house supply of FDG radiopharmaceuticals. Nihon Hoshasen Gijutsu Gakkai Zasshi 70(4):339–345 (in Japanese)CrossRefPubMedGoogle Scholar
  15. 15.
    McKeown C, Gillen G, Dempsey MF, Findlay C (2016) Influence of slice overlap on positron emission tomography image quality. Phys Med Biol 61:1259–1277CrossRefPubMedGoogle Scholar
  16. 16.
    El Fakhri G, Surti S, Trott CM, Scheuermann J, Karp JS (2011) Improvement in lesion detection with whole-body oncologic time-of-flight PET. J Nucl Med 52(3):347–353CrossRefPubMedPubMedCentralGoogle Scholar
  17. 17.
    Fukukita H, Suzuki K, Matsumoto K, Terauchi T, Daisaki H, Ikari Y et al (2014) Japanese guideline for the oncology FDG-PET/CT data acquisition protocol: synopsis of Version 2.0. Ann Nucl Med 28:693–705CrossRefPubMedPubMedCentralGoogle Scholar
  18. 18.
    Yonei Y, Miwa Y, Hibino S, Takahashi Y, Miyazaki R, Yoshikawa T et al (2008) Japanese anthropometric reference data: special emphasis on bioelectrical impedance analysis of muscle mass. Anti-Aging Med 5:63–72CrossRefGoogle Scholar
  19. 19.
    Osawa A, Miwa K, Wagatsuma K, Takiguchi T, Tamura S, Akimoto K (2012) Relationship between image quality and cross-sectional area of phantom in three-dimensional positron emission tomography scan. Nihon Hoshasen Gijutsu Gakkai Zasshi 68:1600–1607 (in Japanese)CrossRefPubMedGoogle Scholar
  20. 20.
    Macdonald LR, Schmitz RE, Alessio AM, Wollenweber SD, Stearns CW et al (2008) Measured count-rate performance of the Discovery STE PET/CT scanner in 2D, 3D and partial collimation acquisition modes. Phys Med Biol 53:3723–3738CrossRefPubMedPubMedCentralGoogle Scholar
  21. 21.
    Masuda Y, Kondo C, Matsuo Y, Uetani M, Kusakabe K (2009) Comparison of imaging protocols for 18F-FDG PET/CT in overweight patients: optimizing scan duration versus administered dose. J Nucl Med 50(6):844–848CrossRefPubMedGoogle Scholar
  22. 22.
    Halpern BS, Dahlbom M, Quon A, Schiepers C, Waldherr C et al (2004) Impact of patient weight and emission scan duration on PET/CT image quality and lesion detectability. J Nucl Med 45:797–801PubMedGoogle Scholar
  23. 23.
    Boellaard R, Krak NC, Hoekstra OS, Lammertsma AA (2004) Effects of noise, image resolution, and ROI definition on the accuracy of standard uptake values: a simulation study. J Nucl Med 45:1519–1527PubMedGoogle Scholar
  24. 24.
    Sibille L, Chambert B, Alonso S, Barrau C, D’Estanque E, Al Tabaa Y et al (2016) Impact of the adaptive statistical iterative reconstruction technique on radiation dose and image quality in bone SPECT/CT. J Nucl Med 57(7):1091–1095CrossRefPubMedGoogle Scholar
  25. 25.
    Hara AK, Paden RG, Silva AC, Kujak JL, Lawder HJ, Pavlicek W (2009) Iterative reconstruction technique for reducing body radiation dose at CT: feasibility study. AJR Am J Roentgenol 193:764–771CrossRefPubMedGoogle Scholar
  26. 26.
    Cohade C, Osman M, Nakamoto Y, Marshall LT, Links JM et al (2003) Initial experience with oral contrast in PET/CT: phantom and clinical studies. J Nucl Med 44:412–416PubMedGoogle Scholar
  27. 27.
    Park SJ, Ionascu D, Killoran J, Mamede M, Gerbaudo VH et al (2008) Evaluation of the combined effects of target size, respiratory motion and background activity on 3D and 4D PET/CT images. Phys Med Biol 53:3661–3679CrossRefPubMedGoogle Scholar

Copyright information

© Australasian College of Physical Scientists and Engineers in Medicine 2017

Authors and Affiliations

  1. 1.Department of Nuclear MedicineCancer Institute Hospital of Japanese Foundation for Cancer ResearchTokyoJapan
  2. 2.Department of Radiological Sciences, School of Health SciencesInternational University of Health and WelfareTochigiJapan
  3. 3.Department of RadiologyChiba University HospitalChiba-shiJapan
  4. 4.Research Team for NeuroimagingTokyo Metropolitan Institute of GerontologyTokyoJapan

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