Multi-centre evaluation of accuracy and reproducibility of planar and SPECT image quantification: An IAEA phantom study

Research output: Contribution to journalArticle


Accurate quantitation of activity provides the basis for internal dosimetry of targeted radionuclide therapies. This study investigated quantitative imaging capabilities at sites with a variety of experience and equipment and assessed levels of errors in activity quantitation in Single-Photon Emission Computed Tomography (SPECT) and planar imaging. Participants from 9 countries took part in a comparison in which planar, SPECT and SPECT with X ray computed tomography (SPECT-CT) imaging were used to quantify activities of four epoxy-filled cylinders containing 133Ba, which was chosen as a surrogate for 131I. The sources, with nominal volumes of 2, 4, 6 and 23mL, were calibrated for 133Ba activity by the National Institute of Standards and Technology, but the activity was initially unknown to the participants. Imaging was performed in a cylindrical phantom filled with water. Two trials were carried out in which the participants first estimated the activities using their local standard protocols, and then repeated the measurements using a standardized acquisition and analysis protocol. Finally, processing of the imaging data from the second trial was repeated by a single centre using a fixed protocol. In the first trial, the activities were underestimated by about 15% with planar imaging. SPECT with Chang's first order attenuation correction (Chang-AC) and SPECT-CT overestimated the activity by about 10%. The second trial showed moderate improvements in accuracy and variability. Planar imaging was subject to methodological errors, e.g., in the use of a transmission scan for attenuation correction. The use of Chang-AC was subject to variability from the definition of phantom contours. The project demonstrated the need for training and standardized protocols to achieve good levels of quantitative accuracy and precision in a multicentre setting. Absolute quantification of simple objects with no background was possible with the strictest protocol to about 6% with planar imaging and SPECT (with Chang-AC) and within 2% for SPECT-CT.


  • Brian E Zimmerman
  • Darko Grošev
  • Irène Buvat
  • Marco A Coca Pérez
  • Eric C Frey
  • Alan Green
  • Anchali Krisanachinda
  • Michael Lassmann
  • Michael Ljungberg
  • Lorena Pozzo
  • Kamila Afroj Quadir
  • Mariella A Terán Gretter
  • Johann Van Staden
  • Gian Luca Poli
External organisations
  • University Hospital Centre Zagreb
  • Service Hospitalier Frédéric Joliot
  • Medscan Concepción
  • Johns Hopkins University
  • National Physical Laboratory, UK
  • Chulalongkorn University
  • Julius Maximilian University of Würzburg
  • Institute of Energy and Nuclear Research, Brazil
  • National Institute of Nuclear Medicine & Allied Sciences, Dhaka, Bangladesh.
  • University of the Republic
  • University of the Free State
  • International Atomic Energy Agency (IAEA)
  • National Institute of Standards and Technology (NIST)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Medical Laboratory and Measurements Technologies
  • Radiology, Nuclear Medicine and Medical Imaging


  • Humans, Image Processing, Computer-Assisted, Phantoms, Imaging/standards, Radiometry, Reproducibility of Results, Tomography, Emission-Computed, Single-Photon/methods
Original languageEnglish
Pages (from-to)98-112
Number of pages15
JournalZeitschrift fur Medizinische Physik
Issue number2
Publication statusPublished - 2017 Jun
Publication categoryResearch

Bibliographic note

Copyright © 2016. Published by Elsevier GmbH.