A study of 18F-MAA on lung perfusion imaging and the pre-operative assessment of hepatic radioembolization therapy

Autor: Jia-Wei Kuo, 郭家偉
Rok vydání: 2010
Druh dokumentu: 學位論文 ; thesis
Popis: 98
Purpose: 99mTc-labeled macroaggregated albumin (99mTc-MAA) scintigraphy scan is routinely performed for lung perfusion imaging and for the assessment of in-vivo distribution of 90Y-labeled SIR-Spheres? prior to selective internal radiation treatment for hepatocellular carcinoma. It is commonly recognized that positron emission tomography (PET) imaging is superior to gamma scintigraphy in terms of sensitivity, spatial resolution and accuracy of quantification. This study aims to develop a novel 18F-MAA as a PET imaging surrogate for 99mTc-MAA. Materials and methods: By conjugation of MAA (0.5 mg) with N-succinimidyl 4-[18F]fluorobenzoate, 18F-MAA was prepared with high radiochemical yield of ~60% and high purify of ~95%. The size distribution of MAA and 18F-MAA were assessed by using Beckman Coulter Counter LS320. The in-vivo stability of 18F-MAA and 99mTc-MAA was assessed in normal Sprague Dawley rat (SD rat) after intravenous injection of radiotracers. The biodistribution and imaging studies were performed in N1S1 hepatoma-bearing SD rats after intrahepatic arterial co-injection of these two raiotracers. Results: There was no significant difference in size distribution between 18F-MAA and MAA (34.9 ± 23.5 μm and 26.6 ± 18.2 μm, respectively). High in vitro and in vivo stability of the 18F-MAA at least up to 120 min was observed, this would be long enough for clinical studies. The radioactivity distribution after intravenous injection of 18F-MAA and 99mTc-MAA in normal rats revealed that most of the aggregated albumins were trapped in the lungs (91.8 and 86.9 %ID at 15 min p.i.; 77.1 and 75.4 %ID at 2 h p.i., respectively), while all other organs showed relatively low radioactivity accumulation. The highly correlated tumor-to-liver ratio (R2=0.965) and liver-to-lung ratio (R2=0.987) between 18F-MAA and 99mTc-MAA indicated very similar biological characteristics of these two radiolabeled aggregated albumins. As was observed in the biodistribution studies, similar uptakes of 18F-MAA and 99mTc-MAA in tumor and normal organs were noted in the microPET/SPECT/CT imaging. Conclusion: An efficient and convenient preparation of 18F-MAA was successfully developed in this study via a one-step conjugation of 18F-SFB with MAA. 18F-MAA showed similar distribution pattern compared with 99mTc-MAA both in the normal rats and in the hepatoma-bearing rat model. The findings, taken together, exhibited that 18F-MAA is a potential PET surrogate of 99mTc-MAA for clinical applications.
Databáze: Networked Digital Library of Theses & Dissertations
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