Van Audenhaege, Karen

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Ghent University Academic Bibliography

Optimization of collimator combinations for brainSPECTKaren Van AudenhaegeSupervisor(s): S. VandenbergheI. INTRODUCTIONSingle Photon Emission Computed Tomog-raphy (SPECT) is a frequently used biomedicalimaging technique which visualizes functionalprocesses based on the emission of γ-rays fromwithin the body. A SPECT camera consists oftwo main functional components: the collima-tor (to select photons from a certain direction)and the radiation detector. It is mainly the col-limator that defines sensitivity and spatial reso-lution, two important measures of image qual-ity. Typically, a higher resolution results in alower sensitivity.The goal of this project is to realize a newspecialized SPECT system for brain imagingwith a better image quality compared to exist-ing systems by focussing on innovative colli-mator design.II. METHODSPrevious research has shown that the qualityof SPECT images can be improved by com-bining a high-resolution (HR) collimator witha high-sensitivity (HS) collimator, instead of asystem with only HR or only HS [1]. In thisproject, three collimators will be designed andcombined (see Figure 1): a multi-pinhole col-limator for high-resolution, a cone-beam col-limator with ultra-short focal length for highsensitivity [2] and a fan-beam collimator tosolve the problem of data-incompleteness. Toinvestigate the different designs and combina-—————————————————–K. Van Audenhaege is with MEDISIP, a researchgroup of the faculty of engineering at the Universityof Ghent.tions, a Monte Carlo simulator will be used.Some simulations where already performedto study sensitivity for tilted pinholes. The re-sults show that penetration plays an importantrole (up to 15% for a pinhole with an openingangle of 45◦) and is highly dependent on thepinhole design. The simulations will be vali-dated by measurements on a prototype multi-pinhole collimator.Figure 1. Combination of a multi-pinhole, cone-beam and fan-beam collimator.III. CONCLUSIONSA high-sensitivity collimator, a high-resolutioncollimator and a collimator for data sufficiencywill be designed and optimally combined in or-der to achieve a better image quality than withexisting brain SPECT systems.REFERENCES[1] R. Van Holen, Combined high-resolution andhigh-sensitivity collimation provides better im-age quality in SPECT Abstract book 56th SNMannual meeting. supplement1, 2009.[2] M. Park, S. C. Moore and M. F. Kijewski, BrainSPECT with short focal-length cone-beam colli-mation Medical Physics, volume 32, 2005.

Optimization of collimator combinations for brain SPECT

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Optimization of collimator combinations for brain SPECT

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Ghent University Academic Bibliography