Total Body PET/CT: A Role in Drug Development?

Nowadays, total body PET has already entered the medical centers and enabled various clinical applications due to its superior imaging capabilities, especially the high sensitivity. However, the potential of the total body PET in the clinical evaluation of radiopharmaceuticals remains underexplored. The development and regulatory processes for radiopharmaceuticals present unique challenges that total body PET could address. In the safety evaluation of radiopharmaceuticals, the internal radiation dosimetry demands images with high quality and quantitative accuracy, which can be achieved using the total body PET. The current clinical pharmacokinetic study for radiopharmaceuticals still relies on invasively sampling of blood and other body fluid, causing discomfort of participant and difficulty in implementation. With the total body PET, the radioactive concentration of the drug in various blood vessels can be assessed noninvasively, facilitating the pharmacokinetic study. The parametric analysis over the total body based on compartment models also sheds light on the pharmacokinetics of the radiopharmaceutical. A special requirement for multi-center clinical research involving PET and SPECT is the harmonization of the quantitative performance among different imaging equipment, and the discrepancy between the total body PET and short axial field of view PET scanners may add to the complexity. To date, there are several successful examples of clinical trials of innovative radiopharmaceuticals using the total body PET, involving different types of tracers ranging from small molecules, peptides, nanobodies, minibodies, and aptamers. In conclusion, total body PET has the potential to revolutionize the clinical evaluation of radiopharmaceuticals and will play a crucial role in future drug development.