Feasibility study of Y-90 radioembolization post-treatment dosimetry with a long axial field-of-view PET/CT

Ziel/Aim Individual treatment planning and verification play a pivotal role in applying selective internal radiation therapy (SIRT) safely and for achieving the best possible treatment outcome. The purpose of our study is to assess the feasibility of using the long axial field-of-view (LAFOV) Biograph Vision Quadra PET/CT (Siemens Healthineers) for post-treatment dosimetry SIRT and to compare the impact of different imaging modalities on the treatment verification.

Methodik/Methods We use a clinically available long axial field-of-view (LAFOV) PET/CT scanner to image patients that were treated with Y-90 microspheres. For the post-treatment dosimetry the patients are imaged twice, once with SPECT/CT and once with LAFOV PET/CT. We use Simplicit90Y (Boston Scientific) to compute the doses for both imaging modalities, based on the ROI from the Tc-99m MAA SPECT/CT. A quantitative comparison of Y-90 imaging and post-treatment dosimetry with SPECT/CT, standard FOV and LAFOV PET/CT using phantom measurements are planned as well.

Ergebnisse/Results We could include eight patients in this analysis. LAFOV PET/CT can overcome the small branching of the Y-90 decay to the 0+state of Zr-90 and provide a high image quality with 20 minutes of acquisition time. As an example, for one subject the resulting perfused tumor dose is 88.5% and 73.7% of the planned dose for SPECT and PET, respectively. For the same patient the whole liver dose is 125.3% (SPECT) and 196.5% (PET) of the planned dose, while the dose to the lung is almost the same for both modalities.

Schlussfolgerungen/Conclusions In this study we demonstrate for the first time that treatment verification of Y-90 SIRT with a LAFOV PET/CT and commercial software products is possible and that this is a viable option in clinical routine. Because of the improved image quality, we believe the post-treatment dosimetry based LAFOV PET/CT images to be more accurate compared to SPECT/CT. A quantitative comparison of LAFOV PET and SPECT to address this question is forthcoming.

Publication History

Article published online:
14 April 2022