Accurate non-tumoral 99mTc-MAA absorbed dose prediction to plan optimized activities in liver radioembolization using resin microspheres.
AIM
The manufacturers' recommended methods to calculate delivered activities in liver radioembolization are simplistic and only slightly personalized. Activity planning could also be based on a 99mTc-macroaggregated albumin SPECT/CT (MAA) using the partition model but its accuracy is controversial. This study evaluates the dose parameters in the normal liver and in the tumor compartments using MAA SPECT/CT (pre-therapeutic imaging) and 90Y TOF-PET/CT (post-therapy imaging). Finally, we propose a prescription of the activity as a function of the normal liver MAA distribution.


METHOD
66 procedures of RE (with resin microspheres) corresponding to 171 lesions were analyzed. Tumor to normal targeted liver uptake (T/NTL), tumor absorbed dose (TD) and whole normal liver absorbed (WNLD) were assessed with MAA and 90Y imaging. Secondly, activities were recalculated using the MAA distribution in the normal liver compartment to reach the maximal tolerable liver dose. These Activities were compared to activities defined with the BSA method.


RESULTS
Compared to 90Y imaging, our study demonstrated an accurate estimation of the WNLD using MAA imaging (Pearson's R = 0.97, p < 0.001). On the contrary, significant variations were found for TD (R = 0.65, p < 0.001). The MAA T/NTL ratio has a 85% positive predictive value in identifying patients who will get a 90Y T/NTL ratio above 1.5. Moreover, activities calculated using the MAA distribution in the normal liver compartment were significantly higher to activities defined with the BSA method.


CONCLUSION
Whole normal liver absorbed doses are accurately predicted with MAA imaging and could be used to optimize the activity planning.
["d'Abadie|Philippe|P|", 'Walrand|Stephan|S|', 'Hesse|Michel|M|', 'Amini|Nadia|N|', 'Lhommel|Renaud|R|', 'Sawadogo|Kiswendsida|K|', 'Jamar|François|F|']
D000418:Albumins D006528:Carcinoma, Hepatocellular D004621:Embolization, Therapeutic D006801:Humans D008113:Liver Neoplasms D008863:Microspheres D000072078:Positron Emission Tomography Computed Tomography D012189:Retrospective Studies D013668:Technetium Tc 99m Aggregated Albumin D015899:Tomography, Emission-Computed, Single-Photon D015021:Yttrium Radioisotopes
Radioembolization Partition model (90)Y PET/CT (99)Tc-MAA SPECT/CT Dosimetry