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See detailQuantitative capabilities of four state-of-the-art SPECT-CT cameras
Seret, Alain ULg; Nguyen, Daniel ULg; BERNARD, Claire ULg

in European Journal of Nuclear Medicine and Molecular Imaging Research (2012), 2

Background. Four state-of-the-art single-photon emission computed tomography-computed tomography (SPECT-CT) systems, namely Philips Brightview, General Electric Discovery NM/CT 670 and Infinia Hawkeye 4 ... [more ▼]

Background. Four state-of-the-art single-photon emission computed tomography-computed tomography (SPECT-CT) systems, namely Philips Brightview, General Electric Discovery NM/CT 670 and Infinia Hawkeye 4, and Siemens Symbia T6, were investigated in terms of accuracy of attenuation and scatter correction, contrast recovery for small hot and cold structures, and quantitative capabilities when using their dedicated three-dimensional iterative reconstruction with attenuation and scatter corrections and resolution recovery. Methods. The National Electrical Manufacturers Association (NEMA) NU-2 1994 phantom with cold air, water, and Teflon inserts, and a homemade contrast phantom with hot and cold rods were filled with 99mTc and scanned. The acquisition parameters were chosen to provide adequate linear and angular sampling and high count statistics. The data were reconstructed using Philips Astonish, General Electric Evolution for Bone, or Siemens Flash3D, eight subsets, and a varying number of iterations. A procedure similar to the one used in positron emission tomography (PET) allowed us to obtain the factor to convert counts per pixel into activity per unit volume. Results. Edge and oscillation artifacts were observed with all phantoms and all systems. At 30 iterations, the residual fraction in the inserts of the NEMA phantom fell below 3.5%. Contrast recovery increased with the number of iterations but became almost saturated at 24 iterations onwards. In the uniform part of the NEMA and contrast phantoms, a quantification error below 10% was achieved. Conclusions. In objects whose dimensions exceeded the SPECT spatial resolution by several times, quantification seemed to be feasible within 10% error limits. A partial volume effect correction strategy remains necessary for the smallest structures. The reconstruction artifacts nevertheless remain a handicap on the road towards accurate quantification in SPECT and should be the focus of further works in reconstruction tomography. [less ▲]

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See detailQuantitative capabilities of current commercial SPECT-CT systems
Bernard, Claire ULg; Nguyen, Daniel ULg; Seret, Alain ULg

Poster (2011, October 27)

Aim: To assess the quantitative capabilities of commercial SPECT-CT systems with their full 3D iterative reconstruction which includes resolution recovery, attenuation and scatter corrections. Materials ... [more ▼]

Aim: To assess the quantitative capabilities of commercial SPECT-CT systems with their full 3D iterative reconstruction which includes resolution recovery, attenuation and scatter corrections. Materials and methods: A NEMA NU2-1994 attenuation and scatter correction accuracy phantom, a cylindrical phantom with uniform part, cold and hot rods (diameter 4-25 mm), three uniform cylindrical phantoms of different sizes were scanned on a Siemens Symbia T6, a Philips BrightView XCT and a GE Infinia Hawkeye 4. For each phantom, activity concentration was obtained from the technetium-99m activity measured with an activimeter and its water volume. Emission projections were collected for 128 angles over 360 in 128*128 matrix (pixel size of 2.7 mm) using the 140 keV system usual energy window, and standard CT attenuation protocol was executed. Full 3D iterative reconstructions (Siemens Flash3D, Philips Astonish, GE Evolution) were performed. Residual fraction (RF) in the cold inserts of the NEMA phantom, contrast recovery coefficient (CRC) in the cold and hot rods were computed from the images. Regions of interest (ROI) of different sizes (60-100% of the phantom physical size) were drawn on the three uniform phantoms to obtain a calibration factor (CF). Results: RF dropped below 4% and CRC almost stabilized after 18 iterations. Hot rod CRC were above 90% for the rods with a diameter larger than 16 mm rising above 100% in some cases. Accurate quantification was shown feasible to within 5% or even less on some systems. CF was found to depend on both the phantom and the ROI sizes used for its determination, with variation of a few percents to more than 10%. The best phantom/ROI combination was also dependent on the system. Conclusion: With a careful design of the calibration procedure, quantification with these SPECT-CT systems and 3D iterative reconstruction seems to be feasible. However partial volume effect will remain a concern when object size drops below 2 cm. [less ▲]

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See detailViability for the Siemens Ecat HR+ of the new stability test of PET scanners elaborated by the Belgian Hospital Physicist Association
Nguyen, Daniel ULg; Dalemans, Christophe; Bahri, Mohamed Ali ULg et al

in European Journal of Nuclear Medicine and Molecular Imaging (2011, October), 38(S2), 174

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See detailQuantitative capabilities of the Siemens Symbia T6 SPECT-CT system with iterative Flash3D reconstruction
Nguyen, Daniel ULg; Seret, Alain ULg; Bernard, Claire ULg

in European Journal of Nuclear Medicine and Molecular Imaging (2011, October), 38(S2), 223

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See detailPotentialités quantitatives et qualité d'image de la camera TEMP/TDM Siemens Symbia T6
Seret, Alain ULg; Nguyen, Daniel ULg; HUSTINX, Roland ULg et al

in Médecine Nucléaire : Imagerie Fonctionnelle et Métabolique (2011, May 07), 35

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See detailViabilité pour le Siemens ECAT EXACT HR+ du test de stabilité des tomographes TEP élaboré par la société belge des physiciens d'hôpitaux
Seret, Alain ULg; Dalemans, Christophe ULg; Nguyen, Daniel ULg et al

in Médecine Nucléaire : Imagerie Fonctionnelle et Métabolique (2011, May 07), 35

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