A New Method for Co-registering PET and CT Images Acquired in Separate Dedicated Small Animal Scanners
Abstract (Set) Background - Positron Emission Tomography in dedicated small animal scanners is a very attractive imaging modality for many research applications due to the high sensitivity and potential for absolute quantification. However, PET images, although revealing valuable functional information, are of poor morphological detail. In addition, accurate absolute quantification requires attenuation correction of the emission data, a task that is challenging in these small animal scanners, when they are not part of a combined PET/CT system, since the only alternative (transmission scans) is prone to significant errors in these systems. Purpose - We developed a novel method for accurate co-registration ofmicro-PT and micro-CT images (which allowed the simultaneous display of functional and anatomical data and the attenuation correction of the PET data using the CT images) obtained in separate small animal scanners. Results - Succesful co-registration of PET and CT images was achieved in all animals. Injection sites of the radiolabelled cells were identified in the myocardium (bright spots by PET superimposed in the myocardial CT image). The accuracy of the coregistration was confirmed by the 13NH3 perfusion images, which localized the injection sites within the myocardium. In addition, presence of cells within the lungs was revealed by the fused PET/CT images (migration from the injection sites). More importantly, an attenuation coeffcient was calculated for all animals (average 43%), that allowed accurate quantification of the percentage of cells that persisted in the myocardium, Ihr after intramyocardial delivery. Conclusion - This novel method for co-registering PET and CT images obtained in separate small animal scanners, allows the combination of functional and anatomical data obtained by these two different modalities and the performance of accurate attenuation corrected absolute quantification of the PET data, in an easy and reproducible manner, without the need for investing in expensive hybrid PET/CT systems. Description (Set) Proposed Use (Set)Inventor(s): Marban, Eduardo ,Abraham, Maria Roselle,Terrovitis, Ioannis
Type of Offer: Licensing
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