Long‐Acting Dynamic Therapy Using X‐Ray Activated Organic Nanoparticles for Afterglow Imaging Guided Deep Tumor Treatment

ABSTRACT Traditional dynamic therapies, including photodynamic, sonodynamic and chemodynamic therapies, are limited by shallow penetration and lack of sustained effects. X‐ray induced dynamic therapy overcomes penetration barriers, yet current inorganic materials raise biosafety concerns, while organic counterparts often show low reactive oxygen species (ROS) yield. To address these limitations, we propose X‐ray induced long‐acting dynamic therapy, a minimally invasive strategy for deep‐tissue tumor treatment. We propose X‐ray induced persistent ROS generation and luminescence mechanisms in fused‐triple‐anthracene nanoparticles (FTA NPs), which generate electrons and FTA •+ under X‐ray irradiation to producing singlet oxygen ( 1 O 2 ) and hydroxyl radicals (OH), while endoperoxides (EPOs) sustain ROS and afterglow luminescence for over 15 min, with relatively stronger afterglow than conventional organic afterglow materials, such as MEHPPV NPs. In addition, FTA NPs achieve 6 cm tissue penetration under X‐ray, overcoming light limitations and boosting therapeutic efficacy. Furthermore, we introduce fractionated irradiation, splitting high doses into multiple low‐dose sessions, which enhances ROS generation, reduces radiation risk and more effectively treats subcutaneous and orthotopic pancreatic tumors than continuous irradiation. Strong afterglow luminescence allows real‐time imaging and treatment monitoring, while metal‐free FTA NPs ensure high biocompatibility and safety. Thus, long‐acting dynamic therapy offers a safe and efficient strategy for deep‐seated tumors.