RT Journal Article
SR Electronic
T1 Pharmacokinetics of <sup>99m</sup>Tc-MAA and <sup>99m</sup>Tc-HSA-Microspheres used in pre-Radioembolization Dosimetry – Influence on the Liver-Lung Shunt
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP jnumed.115.169987
DO 10.2967/jnumed.115.169987
A1 Grosser, Oliver
A1 Ruf, Juri
A1 Kupitz, Dennis
A1 Pethe, Annette
A1 Ulrich, Gerhard
A1 Genseke, Philipp
A1 Mohnike, Konrad
A1 Pech, Maciej
A1 Richter, Wolf Stefan
A1 Ricke, Jens
A1 Amthauer, Holger
YR 2016
UL http://jnm.snmjournals.org/content/early/2016/02/08/jnumed.115.169987.abstract
AB Perfusion scintigraphy (PS) using technetium-99m (99mTc) labeled albumin-aggregates is a mandatory step before hepatic radioembolization (RE) with yttrium-90-labeled microspheres. Within the bounds of a prospective clinical trial, this sub-analysis assessed the intrahepatic and intrapulmonary stability of two albumin-compounds, 99mTc-MAA (macroaggregated serum albumin, MAA) and 99mTc-HSA (human serum albumin, HSA) after intra-arterial injection. Methods: In n = 24 patients (age: 64.6y: 46.2-82.2) with metastatic colorectal cancer (mCRC), PS-data of both tracers were analyzed (n = 12 patients each). Biodistribution (liver, lung) and liver-lung shunt (LLS) was assessed by sequential planar scintigraphy (1h, 5h and 24h post intra-hepatic/intra-arterial injection; p.i.) using the region of interest (ROI) technique. Data were corrected for radioactive decay. Results: Liver uptake of MAA decreased significantly from 1h (median particle uptake=70.0%) to 5h (45.5%, p&lt;0.0001) and 24h (27.9%, p&lt;0.0001), respectively. MAA-uptake in the lungs at first increased significantly from 1h (2.7%) to 5h (3.8%, P = 0.0007) and then decreased significantly from 5h to 24h (3.0%, P = 0.002). HSA-uptake in the liver decreased significantly from 1h (70.2%) to 5h (65.0%, P = 0.0002) and from 1h to 24h (46.6%, p&lt;0.0001). There was no significant change in pulmonary HSA-uptake (1h p.i: 2.4%) between time-points (p≥0.2). Liver-lung shunt (LLS) at 1h p.i. was 3.9% (25th/75th percentiles= 3.3/5.0%; range= 2.4-9.8%) for MAA and 3.2% (2.8/4.1%; 2.0-5.8%) for HSA (P = 0.2). MAA-LLS increased significantly from 1h (median LLS=3.9%) to 5h (7.7%, P = 0.0005) and 24h p.i. (9.9%, p&lt;0.0001), respectively. HSA-LLS did not change significantly from 1h (3.2%) to 5h p.i. (3.5%, P = 0.74) but had increased significantly by 24h p.i. (4.8%, p&gt;0.006). The estimated biologic half-lives of albumin particles were 7.9h/22.4h (bi-exponential fit, adj. R2 = 0.77) and 41.7h (mono-exponential fit, adj. R2 = 0.76) for MAA and HSA, respectively. Conclusion: In comparison to 99mTc-MAA, 99mTc-HSA-microspheres appear to be more resistant to degradation over time, allowing a reliable LLS-determination even at later time-points.