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PET Molecular Imaging of 89Zr-Labeled Monoclonal Antibodies -Solid Target System and Automatic Purification System for 89Zr-

2015; Society of Nuclear Medicine and Molecular Imaging; Volume: 56; Linguagem: Inglês

1535-5667

Jun‐ya Kato, Takashi Oda, Satoshi Ueno, Toru Ishizuka, T. Yano,

Medical Imaging and Pathology Studies

1007 Objectives Monoclonal antibodies are the most rapidly expanding category of therapeutics. Since 89Zr physical half-life of 78.4 hr matches the biological half-life of mAbs and subsequent visualization, PET imaging with 89Zr-labeled antibodies is an attractive imaging modality at several stages of drug development. However, the loading work of metal targets to the biomedical cyclotron has been followed by complicated operations, and the recovery work after radiation to targets has taken much time. And in most cases, 89Zr produced by biomedical cyclotron has been purified by manually and then radiation exposure has been inevitable. Such a technical difficulty can allow only few PET centers to accomplish 89Zr PET imaging for mAbs. In order to seek a good solution, we developed the novel producing and purifying system for 89Zr in existing PET facilities. Methods 1. Solid Target System Since the existing target system for producing 89Zr is adopted, while horizontal irradiation system is utilized, we have developed more suitable 89Y foil from the views of size, irradiation condition and contaminated impurities in our 89Zr process. 2. Automatic Purification System Purification of 89Zr from 89Y and other impurities can be achieved via affinity chromatography using hydroxamate column and QMA resin. We have achieved all the process by automatic purification system. Results 1. Solid Target System The average yield of 89Zr is 15-17 MBq/uAh at an incident energy of 12 MeV, resulting in batches of 300 MBq of 89Zr within 40 min at 25 uA of current. 2. Automatic Purification System Y foil including 89Zr is diluted in 6 M of hydrochloric acid. Those solution is purified by hydoroxamate column eluted with 1 M of oxalic acid. 89Zr is eluted from QMA column using diluted hydrochloric acid, resulting in a product with > 99.9 % radionuclidic purity. Conclusions We will discuss on further validation studies about solid target system and automatic purification system for 89Zr, guiding 89Zr PET imaging for mAbs. Research Support We thank Prof. H. Kumon and Prof. E. Matsuura (Okayama University Medical School) and Prof. Y. Watanabe and Dr. Y. Kanayama (RIKEN Center for Life Science Technologies) for PET molecular imaging of 89Zr-labeled mAbs.