Author: Shengwen Deng, Sven L. Gallo, Robert S. Jones, David W. Jordan, Arashdeep Kaur, Aishwarya M. Kulkarni, Quibai Li, William R.M. Pedersen 👨🔬
Affiliation: Department of Radiology, University Hospitals Cleveland Medical Center; School of Medicine, Case Western Reserve University, Department of Radiology, Radiation Safety, University Hospitals Cleveland Medical Center, Department of Radiology, Radiation Safety, University Hospitals Cleveland Medical Center; School of Medicine, Case Western Reserve University; Department of Radiology, Louis Stokes Cleveland VA Medical Center 🌍
Purpose:
Y-90 (Yttrium) SIRT radioembolization takes advantage of delivering localized radiation to the liver. Pre-treatment dosimetry is highly dependent on accurate MAA mapping, which may have an inconsistent representation of the Y-90 biodistribution and tumor uptake1. In this educational case report, we describe a Y-90 segmentectomy where the initial MAA mapping demonstrated limited tumor uptake.
Methods:
A patient with a localized hepatic tumor in segment III underwent pre-treatment imaging, including 99mTc macroaggregated albumin/sulfur colloid (MAA/SC) mapping fused with MRI/SPECT to assess tumor uptake. The fusion images demonstrated minimal MAA uptake in the tumor bed, raising concerns regarding appropriate radioembolization treatment. Based on the angiographic validation, the interventional radiologist and nuclear medicine physician with the input from the medical physicist, decided to proceed with the treatment using a one-day pre-calibration dose of Y-90 resin microspheres (SIR-Sphere®), to increase number of resin particles & assure proper dose is delivered to the tumor bed, due to multi-vessels branching off.
Results:
Interventional arterial embolization confirmed that the interventional radiologist had successfully catheterized the tumor-feeding arteries, despite the low MAA uptake seen in pre-treatment scans. Following the Y-90 radioembolization procedure, post-treatment imaging confirmed successful uptake of resin microspheres in the tumor bed. No significant adverse events were observed, and the patient's treatment was deemed successful using dosimetry analysis.
Conclusion:
This case highlights the importance of using multimodality imaging techniques and being adaptable in response to unexpected findings. The treatment efficacy will also be validated with a follow-up MRI scan after a few months, post treatment. By assessing the discrepancy of MAA vs. Iodine distribution and adjusting the pre-calibration dose, the team was able to improve microsphere delivery to the tumor. This case highlights the value of collaborative decision-making in complex Y-90 procedures and emphasizes the need for flexibility in treatment protocols.