Scatter correction for planar and SPECT imaging with factor analysis

Abstract

Introduction In order to achieve quantitative data in planar and SPECT imaging, various interactions of photons with matter have to be modelled and compensated. Although correction for photon attenuation has been addressed by including X-ray CT scans, accurate correction for Compton scattering remains an open issue. Purpose In this work we propose and assess a novel, user-independent framework applying factor analysis (FA). Materials and methods Extensive Monte Carlo simulations for planar and tomographic imaging were performed using the SIMIND software. Furthermore a Jaszczak phantom study (Data Spectrum Corporation, Durham, NC, USA) and ten clinical 99 m Tc MDP bone studies were performed using a large-field of view scintillation camera (General Electric’s Infinia Hawkeye). In order to use FA for scatter correction, we subdivided the applied energy window into a number of sub-windows, serving as input data. FA results in two factor images (photo-peak, scatter) and two corresponding factor curves (energy spectra). Results The data obtained by FA showed good agreement with the energy spectra, photo-peak and scatter images obtained in all Monte Carlo simulated data sets. For the Jaszczak phantom, without scatter correction, the cold sphere contrast ranged from −47.7 to −4.75, while with FA scatter correction, it ranged from −51.5 to −7.52. The cold sphere sector contrast ranged from −16.6 to −0.18 for non-scatter corrected data, and for the FA data, from −16.6 to −0.23. Conclusion Factor analysis can be used as a user-independent approach for scatter correction in quantitative nuclear medicine imaging. Disclosure Nothing to disclose.