PET alignment for small animal scanners based on capillary detection

Alexia Rodríguez-Ruano, Javier Pascau, Judit Chamorro, Alejandro Sisniega, Verónica Garcia-Vázquez, Ángel Udías, Juan José Vaquero, Manuel Desco

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Small animal PETICT devices provide anatomical and molecular imaging at the same time, enabling the joint visualization and analysis of both modalities. An accurate PET/CT alignment is required to correctly interpret these studies. A proper calibration procedure is essential for small animal imaging, since resolution is much higher than in human devices. This work presents an alignment phantom and a method that enable a reliable and replicable measurement of the geometrical relationship between PET and CT modules. The phantom can be built with laboratory materials, and is used to estimate the rigid spatial transformation that aligns both modalities. consists of three glass capillaries located in noncoplanar triangular geometry and filled with FDG, so they are easily identified in both modalities. The method is based on automatic line detection and localization of the corresponding points between the lines on both modalities, which allows calculating the rigid alignment parameters. Different geometric configurations of the phantom (i.e. different angles and distances between capillaries) were tested to assess the repeatability of the calculations. To measure the alignment precision achieved, we attached two additional sodium point sources to the phantom,which were neglected in the registration process. Our results show that the accuracy of the alignment estimation, measured as average misalignment of the Na sources, is below half the PET resolution. The alternative settings for the phantom layout did not affect this result, indicating the low dependency of the alignment calculated with the actual phantom layout. Our approach allows measuring the PETICT transformation parameters using an in-house built phantom and with low computational effort and high accuracy, demonstrating that the proposed phantom is suitable for alignment calibration of dual modality systems on a real environment.copy;2008IEEE.

Original languageEnglish (US)
Title of host publication2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008
Number of pages4
StatePublished - 2008
Externally publishedYes
Event2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008 - Dresden, Germany
Duration: Oct 19 2008Oct 25 2008

Publication series

NameIEEE Nuclear Science Symposium Conference Record
ISSN (Print)1095-7863


Other2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging


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