Diverging lung shunt fraction before radioembolisation using different macroaggregate albumins: A matched-pair analysis

Ziel/Aim Estimation of the lung shunt fraction (LSF) before radioembolisation is essential for activity calculation and to avoid pulmonary complications. During pretherapeutical angiography, Tc-99m-marked macroaggregate albumin (MAA) is injected into the hepatic arteries to simulate therapeutic nuclide distribution (including detection of extrahepatic abdominal shunts and determination of the LSF). In this study, we retrospectively analysed the behaviour of two different MAA radiopharmaceuticals onto the LSF.

Methodik/Methods To 66 consecutive patients receiving (A) Pulmocis® (CIS bio GmbH) for radioembolisation evaluation, we matched 66 patients previously evaluated with (B) TechneScan® LyoMAA (Mallinckrodt Medical B.V.). Cases were matched regarding sex (male/female 27/39 in each cohort), age (63±13 years vs. 65±10 years), cancer type (e.g. 9 hepatocellular, 18 colorectal, 18 cholangiocellular, and 10 breast cancer, each, etc.), liver size (median 1863 [1200-4586] ml vs. 1866 [1190-3717] ml), and tumor burden (median 14.1 % [0.3-55.7 %] vs. 13.5 % [0.8-44.4 %]). LSF was calculated from planar scintigrams of the trunk (2 bed positions) using conventional SPECT/CT gamma camera (GE NM/CT 670, GE Healthcare).

Ergebnisse/Results The LSF calculated using radiopharmaceutical (A) was significantly lower than using (B): mean 3.7 % vs. 6.4 %, median 3.2 % [1.5-10.9 %] vs. 6.0 % [2.4-15.7 %], p < 0.0001 (Wilcoxon’s test). Despite different LSF, no adverse events related to the lungs were reported in both cohorts, while applying body surface area (BSA) or modified BSA model for activity prescription.

Schlussfolgerungen/Conclusions The use of different MAA radiopharmaceuticals is likely to affect the LSF significantly and may thus potentially influence activity prescription for radioembolisation. The observed effect might hypothetically be traced to different pharmacokinetic properties (e.g. albumin particle size and its distribution). However, the observation needs to be further substantiated in a prospective setting.