**Preface to "In Vivo Nuclear Molecular Imaging in Drug Development and Pharmacological Research"**

Molecular imaging is a valuable tool for the real-time visualization of biological processes at the molecular level in intact living subjects. Nuclear molecular imaging has been receiving increasing attention due to its high sensitivity and critical role in precision medicine, as well as its use for personalized care in patient management. This Special Issue of *Pharmaceuticals*, "In Vivo Nuclear Molecular Imaging in Drug Development and Pharmacological Research", features original and review articles related to in vivo molecular imaging, including topics of PET imaging modality, in drug development and pharmacological research. The Special Issue published one editorial, eight articles and four reviews from approximately one hundred authors. It aimed to provide cutting-edge research on pre-clinical development and the clinical translation of radiopharmaceuticals within the molecular imaging community. The Special Issue covered radioligand development, existing radiotracer optimization, imaging agent evaluation in animal models, the clinical production of radiopharmaceuticals, and investigative research on the use of molecular imaging probes in human subjects. We appreciate all the authors' significant contributions to this Special Issue and hope the readers will enjoy the content.

> **Xuyi Yue** *Editor*
