X ‐Ray‐Induced Photodynamic Therapy for Deep‐Seated Tumors

Photodynamic therapy (PDT) has shown remarkable efficacy in treating superficial cancers, but the issue of limited penetration depth with visible light excitation has spurred many innovative solutions. Due to the nearly unlimited penetration depth of X-rays in living tissues and organisms, X-ray technology is an ideal method for activating nanosystems for cancer treatment and biomedical imaging applications. Creatively harnessing penetrating X-rays as an external excitation source has led to significant advancements in improving traditional PDT treatments for deep-seated tumors over the past few years. This chapter describes the concept of X-ray-activated PDT, outlines the interaction mechanisms between X-rays and nanosystems, and introduces the application of X-ray-sensitive materials and X-ray-activated nanosystems in PDT for deep-seated tumors. The chapter also provides some prospects for the future development of X-ray-induced PDT.