e-Περιοδικό Επιστήμης & Τεχνολογίας

e-Journal of Science & Technology, (e-JST)

 A novel flood source used for the MTF determination in SPECT systems

 G. Fountos¹, A. Zanglis2, C. Michail³, I. Kalantzis¹, A. Samartzis⁴, D. Cavouras¹, E. Kounadi⁵,
P. Valsamaki², I. Kandarakis¹, S. Gerali² and G. Nikiforidis³

 ¹  Department of Medical Instruments Technology Technological Educational Institution of Athens Ag. Spyridonos, Aigaleo, 122 10 Athens, Greece

² Nuclear Medicine Department, “PAMMAKARISTOS” General Hospital Iakovaton 43, 111 44 Athens, Greece

³ Department of Medical Physics, Medical School University of Patras, 265 00 Patras, Greece

⁴ Nuclear Medicine Department, “EVANGELISMOS” General Hospital Ypsilantou 45-47, 10676 Athens, Greece 

⁵ Department of Medical Physics, “ALEXANDRA” General Hospital Vasilisis Sofias 80, 11528, Athens, Greece

Corresponding author: gfoun@teiath.gr

Abstract. The Modulation Transfer Function (MTF) is an important parameter for the characterization of the signal transfer properties and image quality of a single photon emission computed tomography (SPECT) system. MTF can be derived by determining the line spread function (LSF) from images of a flood source. The method presented here is novel and easy to implement, requires materials commonly found in clinical practice, is robust to aliasing. Furthermore, since this technique is based on the LSF method, reduces measurement noise levels due to greater data averaging than conventional Point Spread Function (PSF)-integration techniques. In an effort to prepare easily, cheaply and reproducibly a Tc-99m-based flood source (E_γ=140 keV), various combinations of films and radiopharmaceuticals were tried. Excellent results were obtained by immersing an Agfa MammoRay HDR Medical X-ray film in a solution of dithiothreitol (DTT, 10^-3 M)/Tc-99m(III)-DMSA (DMSA:Trivalent Technetium-99m-dimercapto-succinic acid, 40 mCi/40 mL) for 30-45 min in the dark. These films exhibited high integral uniformity (CV <1.9%). All imaging experiments were performed in a Siemens e-Cam γ-camera.

 Keywords: SPECT, ^99mTc(III)-DMSA, MTF, LSF, film, flood source.

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