[68Ga]Ga-4HMSA a promising new PET tracer for imaging inflammation

Background Imaging diagnosis of inflammation has been challenging for many years. Inflammation imaging agents commonly used in nuclear medicine, such as [67Ga]Ga-citrate and 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) showed some limitations. The identification of a radiotracer with high specificity and low radiation dose is clinically important. With the commercialization of 68Ge/68Ga generators and the high 68Ga cyclotron production capacity, the study of 68Ga-based tracer for inflammation has increased and shown good potential. In the present work, we report the synthesis of 4HMSA, a new acyclic chelator, and its first investigation for 68Ga complexation and as a new positron emission tomography (PET) imaging agent of inflammation in comparison to [68Ga]Ga-citrate. Results The present experimental studies have shown that the novel [68Ga]Ga-4HMSA is stable allowing imaging of inflammation in a preclinical model of adjuvant- and pathogen-based inflammation involving intraplantar injection of complete Freund’s adjuvant (CFA). We also found that [68Ga]Ga-4HMSA displayed similar uptakes in the inflamed paw than [68Ga]Ga-citrate, which are superior compared to those of contralateral (non-injected) paws at days 1–3 from PET imaging. [68Ga]Ga-citrate accumulated in the upper body of the animal such as the liver, lungs and the heart, whereas the [68Ga]Ga-4HMSA revealed low uptakes in the majority of the organs and was cleared relatively rapidly from blood circulation through the kidneys and bladder. Conclusion The results highlight the potential of [68Ga]Ga-4HMSA as an interesting alternative to [68Ga]Ga-citrate for inflammation imaging by PET. The new PET tracer also offers additional advantages than [68Ga]Ga-citrate in term of dosimetry and lower overall background activity.

125I –Amoxicillin preparation as a guide tracer for inflammation detection

The objective of this study is to label Amoxicillin with radioactive iodine (125I-AC) via direct electrophilic substitution to act as a promising tracer for inflammation imaging. The highest labeling yield of 80% was achieved after studying all the parameters affecting the labeling reaction using Iodogen (IG) as an oxidizing agent. Molecular Modeling Structure was done using MOE program to predict the suitable 125I position. The product structure was established by a cold iodination reaction using Iodine-127. Biological evaluation of (125I-AC) was carried out using groups of inflamed mice with different exogenous agents such as E.Coli and Turpentine oil. The (125I-AC) shows an in vitro stability of about 97% after 24 h.While doing in vivo studies over 4 h, the tracer stability of 99% was observed.

Imaging Inflammation – From Whole Body Imaging to Cellular Resolution

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.