TY - GEN
T1 - PET alignment for small animal scanners based on capillary detection
AU - Rodríguez-Ruano, Alexia
AU - Pascau, Javier
AU - Chamorro, Judit
AU - Sisniega, Alejandro
AU - Garcia-Vázquez, Verónica
AU - Udías, Ángel
AU - Vaquero, Juan José
AU - Desco, Manuel
PY - 2008
Y1 - 2008
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=67649148584&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=67649148584&partnerID=8YFLogxK
U2 - 10.1109/NSSMIC.2008.4774117
DO - 10.1109/NSSMIC.2008.4774117
M3 - Conference contribution
AN - SCOPUS:67649148584
SN - 9781424427154
T3 - IEEE Nuclear Science Symposium Conference Record
SP - 3832
EP - 3835
BT - 2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008
T2 - 2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008
Y2 - 19 October 2008 through 25 October 2008
ER -