Ga 68 -NOTA-CHSg and T c 99 m -CHSg Labeled Microspheres for Lung Perfusion and Liver Radiomicrospheres Therapy Planning

• Published in: International journal of molecular imaging 2013-12, Vol.2013, p.1-9
• Main Authors: Amor-Coarasa, Alejandro, Milera, Andrew, Carvajal, Denny, Gulec, Seza, Leichner, Jared, McGoron, Anthony J.
• Format: Article
• Language: English
• Subjects: Acids; Atoms & subatomic particles; Labeling; Lungs; Medical imaging; Tomography
• ISSN: 2090-1712; 2090-1720
• DOI: 10.1155/2013/279872

Fast biodegradable (12 h < half-life < 48 h) radioactive labeled microspheres are needed for PET and SPECT lung perfusion and radiomicrosphere therapy planning. An emulsion method was used to create 30.1 ±4.8  μ m size range microspheres with biodegradable Chitosan glycol (CHSg). Microspheres were characterized and labeled with Tc 99 m or Ga 68 as an alternative to MAA in perfusion PET and SPECT studies. Surface decoration of CHSg microspheres with p-SCN-Bn-NOTA was performed to increase Ga 68    in vivo stability. Tc 99 m was labeled directly to the CHSg microspheres. Labeling yield and in vitro radiochemical stability were evaluated. In vitro CHSg microsphere degradation half-life was ~24 hours in porcine blood. Labeled microspheres were injected into Sprague Dawley rats and biodistribution was determined after 2 and 4 hours. Both Tc 99 m -CHSg and Ga 68 -NOTA-CHSg were quickly allocated in the lungs after injection. Tc 99 m -CHSg showed 91.6 ± 6.5% and 83.2 ± 4.1% of the decay corrected injected activity remaining in the lungs after 2 and 4 hours, respectively. For the obtained Ga 68 -NOTA-CHSg microspheres, lung allocation was very high with 98.9 ± 0.2% and 95.6 ± 0.9% after 2 and 4 hours, respectively. The addition of p-SCN-Bn-NOTA acts as a radioprotectant eliminating the released Ga 68 activity from the lungs to the bladder protecting the other organs.