DocumentCode :
2611292
Title :
PET/CT alignment for small animal scanners based on capillary detection
Author :
Rodriguez-Ruano, Alexia ; Pascau, Javier ; Chamorro, Judit ; Sisniega, Alejandro ; Garcia-Vázquez, Veronica ; Udias, Angel ; Vaquero, Juan Jose ; Desco, Manuel
Author_Institution :
Unidad de Medicina y CirugÃ\xada Experimental Hospital General Universitario Gregorio Marañón, Madrid, Spain
fYear :
2008
fDate :
19-25 Oct. 2008
Firstpage :
3832
Lastpage :
3835
Abstract :
Small animal PET/CT 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. It consists of three glass capillaries located in non-coplanar 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 PET/CT 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.
Keywords :
Animals; Calibration; Computed tomography; High-resolution imaging; Image analysis; Imaging phantoms; Joints; Molecular imaging; Positron emission tomography; Visualization;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE
Conference_Location :
Dresden, Germany
ISSN :
1095-7863
Print_ISBN :
978-1-4244-2714-7
Electronic_ISBN :
1095-7863
Type :
conf
DOI :
10.1109/NSSMIC.2008.4774117
Filename :
4774117
Link To Document :
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