Next Generation of Solid Target Radionuclide Antibody Conjugates for Tumor Immuno‐Therapy

ABSTRACT Immune checkpoint therapy has emerged as an effective treatment option for various types of cancers. Key immune checkpoint molecules, such as cytotoxic T‐lymphocyte‐associated protein 4 (CTLA‐4), programmed cell death protein 1 (PD‐1), and lymphocyte activation gene 3 (LAG‐3), have become pivotal targets in cancer immunotherapy. Antibodies designed to inhibit these molecules have demonstrated significant clinical efficacy. Nevertheless, the ability to monitor changes in the immune status of tumors and predict treatment response remains limited. Conventional methods, such as assessing lymphocytes in peripheral blood or conducting tumor biopsies, are inadequate for providing real‐time, spatial information about T‐cell distributions within heterogeneous tumors. Positron emission tomography (PET) using T‐cell specific probes represents a promising and noninvasive approach to monitor both systemic and intratumoral immune changes during treatment. This technique holds substantial clinical significance and potential utility. In this paper, we review the applications of PET probes that target immune cells in molecular imaging. The three solid target radio nuclides and imaging of solid target nuclide‐labeled probes.