Euromedim 2006 :1st European Conference on Molecular Imaging Technology

Performance analysis of a low-cost small animal PET/SPECT scanner

11 May 2006, 15:00

15m

Palais du Pharo, Marseille

oral S7 Multimodalities Multi modality

Speaker

Mr Pedro Guerra (Universidad Politecnica de Madrid)

Description

PET and SPECT are nowadays fundamental techniques for the non-invasive monitorization of chemical pathways in living subjects, based on the emitted radiation of a radiolabeled pharmaceutical,, and are regarded as .powerful tools for the research with animal models of human diseases. However, imaging small rodents requirements in terms of resolution are not met by commercial human scanners and therefore several research groups world-wide have designed dedicated small animal scanners[1-5]. In this context, our goal is to specify a low-cost system capable of performing both PET and SPECT studies and adaptable to different geometries. In any case, it is obvious that the performance of the hybrid system must be comparable in terms of sensitivity, count rate and energy resolutions with existing state-of-the art devices of each modality. The aim of this work is to evaluate the expected performance at system level of a 4 detector head PET/SPECT scanner based on an acquisition front-end currently under development, considering a YAP/LSO phoswich detector. The performances estimations are obtained after the description and simulation of the proposed scanner with the Geant4 Application for Tomographic Emission (GATE) v2.2.0. The optical properties of the detector are optimized, in order to determine the optimum crystal finish Point sources and Derenzo phantoms are simulated and reconstructed for both modalities with the STIR library from and also with the ASPIRE software provided by the university of Michigan. The performance of the described setup, expressed in terms of image resolution and sensitivity, is 1.4mm/0.6% for PET (511 KeV) and 2.5mm/0.025% for SPECT (140KeV). These figures are compared with other existing scanners, with the conclusion that they are very close to state-of-the-art machines, despite the reduced number of detectors. These values will enable multimodal simultaneous acquisitions, providing a new insight into related metabolic processes, without sacrificing performance. [1] R. Lecomte, et al., "Design and engineering aspects of a high resolution positron tomograph for small animal imaging", IEEE Transactions on Nuclear Science, vol. 41, pp. 1446 - 1452, 1994. [2] S. Pavlopoulos and G. Tzanakos, "Design and performance evaluation of a high-resolution small animal positron tomograph", IEEE Transactions on Nuclear Science, vol. 43, pp. 3249 - 3255, 1996. [3] D. P. McElroy, et al., "First results from MADPET-II: a novel detector and readout system for high resolution small animal PET," at Nuclear Science Symposium Conference Record, vol. 3, pp. 2043 - 2047, 2003. [4] M. Streun, et al., "A PET system based on data processing of free-running sampled pulses," at Nuclear Science Symposium Conference Record, vol. 2, pp. 693 - 694, 2001. [5] J. Seidel, et al., "Resolution uniformity and sensitivity of the NIH ATLAS small animal PET scanner: Comparison to simulated LSO scanners without depth-of-interaction capability", IEEE Transactions on Nuclear Science, vol. 50, pp. 1347 - 1350, 2003.