Speaker
Description
We are developing a breast PET insert operating in combination with a whole-body (WB) PET/MRI scanner to improve the detectability of small lesions and early metastases. However, additional detector material can introduce attenuation-induced artifacts that degrade WB-PET image quality. We implemented a joint reconstruction with attenuation correction to explicitly handle the different types of coincidence from the insert and the WB-PET and thereby improve the spatial resolution. To quantify the effectiveness of our method, Monte Carlo simulations were performed using $^{22}$Na point sources at different positions to assess spatial resolution, and a hollow-sphere phantom to evaluate image quality and contrast. Insert attenuation reduced detected WB-PET coincidences by 23.6% at the central field-of-view and degraded spatial resolution of WB-PET-only events by up to 3.0 mm $\Delta$FWHM. Nevertheless, the joint reconstruction including coincidences between the insert and the WB-PET recovered spatial resolution, yielding FWHM values of 3.05 mm (x), 2.34 mm (y) and 2.60 (z) mm compared to 7.17 mm (x), 6.08 mm (y), 3.60 mm (z) for the WB-PET-only events. The inclusion of all coincidence types improved the visibility of the sphere inserts in the phantom and increased contrast recovery for the 8 mm sphere from 28% to 33%. Future work will focus on comprehensive image quality assessment, including space-invariant point spread function modeling, scatter correction, and inter-crystal scattering model implementation, followed by evaluation with realistic anthropomorphic phantoms.
Funding: The project is supported by the German Research Foundation (DFG) under grant agreement no. 508064995, and high-performance computer "Lise" at the NHR@ZIB, project no. shb00004.
| Track | PSMR |
|---|---|
| Presentation type | Oral |