A New Approach for Scatter Removal and Attenuation Compensation from SPECT/CT Images

Document Type: Original Article


1 Department of Medical Physics, Mashhad University of Medical Science, Mashhad, Iran

2 Department of Applied Mathematics, School of Mathematical Sciences, Ferdowsi University of Mashhad, Mashhad, Iran

3 Nuclear Medicine Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

4 Department of Nuclear Medicine Wilhelminenspital Vienna, Austria

5 Research Center for Nuclear Medicine, Tehran University of Medical Sciences, Tehran, Iran



In SPECT, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. Many techniques for attenuation and scatter correction have been proposed. An acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. Here, we propose new Maximum Likelihood Expectation Maximization (MLEM) formula to correct scattering and attenuating photons during reconstruction.
Materials and Methods:
In this work, scatters are estimated through Klein-Nishina formula in all iterations and CT images are used for accurate attenuation correction. Reconstructed images resulted from different MLEM reconstruction formula have been compared considering profile agreement, contrast, mean square error, signal-to-noise ratio, contrast-to-noise ratio and computational time.
The proposed formula has a good profile agreement, increased contrast, signal-to-noise (SNR) & contrast-to-noise ratio (CNR), computational time and decreased mean square error (MSE) compared with uncorrected images and/or images from conventional formula.
In conclusion, by applying the proposed formula we were able to correct attenuation and scatter via MLEM and improve the image quality, which is a necessary step for both qualitative and quantitative SPECT images.


1. Buvat I, Rodriguez-Villafuerte M, Todd-Pokropek A, Benali H, Di Paola R. Comparative assessment of nine scatter correction methods based on spectral analysis using Monte Carlo simulations. J Nucl Med 1995; 36:1476-4188.
2. Zaidi H. Scatter modelling and correction strategies in fully 3-D PET. Nucl Med Commun 2001; 22:1181.
3. Bai C, Zeng GL, Gullberg GT. A slice-by-slice blurring model and kernel evaluation using the Klein-Nishina formula for 3D scatter compensation in parallel and converging beam SPECT. Phys Med Biol 2000; 45:1275.
4. Kadrmas DJ, Frey EC, Karimi SS, Tsui BMW. Fast implementations of reconstruction-based scatter compensation in fully 3D SPECT image reconstruction. Phys Med Biol 1999; 43:857.
5. Kulkarni S, Khurd P, Zhou L, Gindi G. Rapid optimization of SPECT scatter correction using model LROC observers. IEEE Nucl Sci Symp Conf Rec 2007; 5:3986-3993.
6. King MA, Glick SJ, Pretorius PH, Wells RG, Gifford HC, Narayanan M,
et al. Attenuation, scatter, and spatial resolution compensation in SPECT. In: Wernick MN, Aarsvold JN, editors. Emission Tomography: The Fundamentals of SPECT and PET. Amsterdam, the Netherlands: Elsevier Academic Press; 2004.p.74-89.
7. Jonsson C, Larsson SA. A spatially varying Compton scatter correction for SPECT utilizing the integral Klein-Nishina cross section. Phys Med Biol 2001; 46:1767.
8. Floyd C, Jaszczak R, Harris C, Coleman R. Energy and spatial distribution of multiple order Compton scatter in SPECT: a Monte Carlo investigation. Phys Med Biol 2000; 29:1217.
9. Wieczorek H. The image quality of FBP and MLEM reconstruction. Phys Med Biol 2010; 55:3161.
10. Slomka PJ, Patton JA, Berman DS, Germano G. Advances in technical aspects of myocardial perfusion SPECT imaging. J Nucl Cardiol 2009; 16:255-276.
11. Kalantari F, Rajabi H, Saghar M. Quantification and reduction of attenuation related artifacts in SPET by applying attenuation model during iterative image reconstruction: a Monte Carlo study. Hell J Nucl Med 2011; 14:278.
12. Segars W, Mahesh M, Beck T, Frey E, Tsui B. Realistic CT simulation using the 4D XCAT phantom. Med Phys 2008; 35:3800.
13. Wackers FJ, Berman DS, Maddahi J, Watson DD, Beller GA, Strauss HW,
et al. Technetium-99m-hexakis-2-methoxy-iso-butyl-isonitrile: human biodistribution, dosimetry, safety and preliminary comparison to thallium-201 for myocardial perfusion imaging. J Nucl Med 1989; 30:301–311.
14. Knoll P, Kotalova D, Köchle G, Kuzelka I, Minear G, Mirzaei S,
et al. Comparison of advanced iterative reconstruction methods for SPECT/CT. Z Med Phys 2012; 22:58-69.
15. Utsunomiya D, Tomiguchi S, Shiraishi S, Yamada K, Honda T, Kawanaka K,
et al. Initial experience with X-ray CT based attenuation correction in myocardial perfusion SPECT imaging using a combined SPECT/CT system. Ann Nucl Med 2005; 19:485-489.
16. Kinahan PE, Hasegawa BH, Beyer T, editors. X-ray-based attenuation correction for positron emission tomography/computed tomography scanners. Semin Nucl Med 2003; 33:166-179.
17. Buck AK, Nekolla S, Ziegler S, Beer A, Krause BJ, Herrmann K,
et al. Spect/Ct. J Nucl Med 2008; 49:1305-1319.
18. Seo Y, Wong KH, Sun M, Franc BL, Hawkins RA, Hasegawa BH. Correction of photon attenuation and collimator response for a body-contouring SPECT/CT imaging system. J Nucl Med 2005; 46:868-877.
19. Teimourian B, Ay M, Zafarghandi MS, Ghafarian P, Ghadiri H, Zaidi H. A novel energy mapping approach for CT-based attenuation correction in PET. Med Phys 2012; 39:2078.
20. Kheruka S, Naithani U, Maurya A, Painuly N, Aggarwal L, Gambhir S. A study to improve the image quality in low-dose computed tomography (SPECT) using filtration. Indian J Nucl Med 2011; 26:14.
21. Hajizadeh M, Oloomi S, P knoll, H Taleshi. A new approach to scatter correction in SPECT images based on Klein_Nishina equation . Iran J Nucl Med 2013; 21,1, 19-25.
22. Hutton BF, Buvat I, Beekman FJ. Review and current status of SPECT scatter correction. Phys Med Biol 2011; 56:R85.
23. Konik AB. Evaluation of attenuation and scatter correction requirements in small animal PET and SPECT imaging: The University of Iowa; 2010.
Oloomi et al Scatter Removal and Attenuation Compensation in SPECT/CT
Iran J Basic Med Sci, Vol. 16, No. 11, Nov 2013
24. Van Holen R, Vandenberghe S, Staelens S, De Beenhouwer J, Lemahieu I. Fast 3D iterative image reconstruction for SPECT with rotating slat collimators. Phys Med Biol 2009; 54:715.
25. ؤrlig إ, Gustafsson A, Jacobsson L, Ljungberg M, Wikkelsِ C. Attenuation correction in quantitative SPECT of cerebral blood flow: a Monte Carlo study. Phys Med Biol 2000; 45:3847.
26. Xiao J, de Wit TC, Staelens SG, Beekman FJ. Evaluation of 3D Monte Carlo–Based Scatter Correction for
99mTc Cardiac Perfusion SPECT. J Nucl Med 2006; 47:1662-1669.
27. Gustafsson A, ؤrlig إ, Jacobsson L, Ljungberg M, Wikkelsِ C. Dual-window scatter correction and energy window setting in cerebral blood flow SPECT: a Monte Carlo study. Phys Med Biol 2000; 45:3431.
28. Lazaro D, El Bitar Z, Breton V, Hill D, Buvat I. Fully 3D Monte Carlo reconstruction in SPECT: a feasibility study. Phys Med Biol 2005; 50:3739.
29. Beekman FJ, de Jong HWAM, van Geloven S. Efficient fully 3-D iterative SPECT reconstruction with Monte Carlo-based scatter compensation. IEEE Trans Med Imaging 2002; 21:867-877.
30. Zeintl J, Vija AH, Yahil A, Hornegger J, Kuwert T. Quantitative accuracy of clinical
99mTc SPECT/CT using ordered-subset expectation maximization with 3-dimensional resolution recovery, attenuation, and scatter correction. J Nucl Med 2010; 51:921-928