Effect of Scatter Limitation Correction with Misregistration between Computed Tomography and Positron Emission...

This study aimed to evaluate the advantage of scatter limitation correction with misregistration between μ-map in the computed tomography attenuation correction and positron emission tomography in PET/CT study.

We used torso phantom including simulated tumor and arms phantom. The CT scan was performed by changing the position of arms phantom after PET scan. Arms phantom movement was out-side direction, in-side direction, and top-side direction by 1-12 cm, respectively. The standardized uptake value (SUV) of simulated tumor and background (B.G.) were evaluated for three specific parameters. Two scatter corrections were performed with scatter correction (SC), and scatter limitation correction (SLC).

The SUV_max of simulated tumor was increased by 2.80% (SC), and 2.78% (SLC) on out-side arms movement. In the SUV_max, SC and SLC were decreased by 28.6%, 9.04% on in-side arms, respectively. SUV_max of the SC, and SLC were increased on top-side arms. The scatter fraction factor (SFF) of SC and SLC were 0.25, 0.25 on out-side 5 cm and were 0.732, 0.391 on in-side 5 cm and were 0.785, 0.434 on top-side 12 cm, respectively.

SLC improved the overestimation of the SUV_max by SC. However, it is necessary to pay attention, in order not to be improved completely. The finding results indicated that SFF was setting 0.40-0.45 in our institute PET/CT system.