ESTRO 2024 - Abstract Book

S3940

Physics - Image acquisition and processing

ESTRO 2024

Material/Methods:

With our Siemens Biograph Vision 600 PET/CT system (figure 1), two studies are performed using a breathing phantom in which a vial filled with 18F-FDG and iodine contrast is inserted to be able to seen on it in the CT image. One of the acquisitions is made by moving the 18F-FDG vial in the anterior-posterior (AP) direction, while the other acquisition is made by moving in the cranial-caudal (CC) direction. Then, for both studies, OncoFreeze AI and static reconstructions are created using an All Pass filter and attenuation correction. Additionaly, 5 patients with 10 lesions were selected to evaluate the influence of both the size and location of the lesions on the SUVmax and MTV values that should be obtained by using or not using the OncoFreeze AI software in the reconstruction. Images were analysed using the Syngo.via software, which draws a VOI around the target lesion that directly gives us both the SUVmax and the MTV, with a threshold for the MTV at 40% of the SUV max .

Figure 1. Siemens Biograph Vison 600 PET/CT and breathing phantom.

The difference of these two parameters between the images reconstructed with both reconstruction methods (static vs OncoFreeze AI) has also been calculated using the following equation:

Δ(%)=(Image OncoFreeze -Image static )/Image static *100 Eq.1

Results: