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001-es BibID:BIBFORM015726
Első szerző:Balkay László (biofizikus)
Cím:Analysis of the minimum detectable activity in the Gemini TF PET scanner / Balkay László, Emri Miklós, Kis Sándor Attila, Galuska László, Trón Lajos
Dátum:2008
Megjegyzések:Lesion detectability in PET investigations is limited by a number of physical and scanning constraints. The aim of this work is to characterize the minimum detectable activity level for the Gemini TF PET scanner varying the parameters such as scan duration, injected activity, target-to-background ratio and object size. Materials & methods The Gemini TF PET scanner has no septa allowing 3D only acquisition and based on the LYSO scintillator. The system timing resolution is about 600 ps. We used the International Electrotechnical Commission (IEC) body phantom set with the six fillable spheres with inner diameters of 10,13,17,22,28 and 37 mm. The four smaller spheres were filled with F18 activity that the target to background (T/B) ratio were 16, 8, 4 and 2, respectively. The cavity of the IEC phantom was filled with F18 water of 12, 4.9 and 2.1 kBq/ml activity concentration for three different acquisition set. The duration of the PET scans were 10 min at all case. In the Gemini TF the data are acquired in list-mode enabling to the user to define any frame length for the image reconstruction. We set the frame length to 1, 3, 6 and 9 min. The images were reconstructed with the manufacturer supplied 3D listmode iterative algorithm with and without TOF kernel. ROIs were drawn on the spheres of the central slices and the contrast recovery coefficients (CRC) and the contrast to noise ratio (CNR) parameters were calculated for any reconstructed images. Results With T/B ratios of 4, 8, 16 the 13, 17, 22 mm spheres were detectable for any frame length and background concentration activity level. When we set the T/B ratio to 2 the number of detectable spheres were depend on the scan duration and background activity, respectively. At the lowest background activity (2.1 kBq/ml) only the 22 mm sphere could be realized for scan length of at least 3 min. The 13 and17 mm spheres were identified at the used highest background activity (12 kBq/ml) and at least 3 min scan duration. In this background level the 22 mm sphere was easily detectable for any scan duration. We also found that the CNR less depends on the total injected activity than scan duration and the weight between them is sensitive to the applied reconstruction kernel (TOF or non-TOF). Conclusion It is possible to visualize sources with T/B ratio of 2 in the case of Gemini TF PET scanner.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idézhető absztrakt
Megjelenés:Nuclear Medicine and Molecular Imaging. - 35 : 2 (2008), p. 338. -
További szerzők:Emri Miklós (1962-) (fizikus) Kis Sándor Attila (1973-) (fizikus) Galuska László (1946-) (belgyógyász, izotópdiagnoszta) Trón Lajos (1941-) (biofizikus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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