21,22 and photothermal therapy (PTT)
23,24), SDT is featured with sufficient tissue-penetrating depth, high therapeutic efficiency, mitigating side effects and low cost, which makes it specific for treating some patients with tumors in deep positions that are challenging to access surgically.
25,26 The therapeutic mechanism of SDT generally involves the sono-cavitation effect using sonosensitizers and the production of highly toxic reactive oxygen species (ROS), predominantly the singlet oxygen (
1O
2), which kills cancer cells directly by inducing necrosis or apoptosis, also known as immunogenic cell death (ICD), and indirectly by damaging vessels or inhibiting neovascularization in tumor tissues and producing tumor-specific immunity.
21,27,28 Although tumor-associated antigens like peptides or proteins may induce antitumor immune effects under the help of immunologic adjuvants, the existing heterogeneity of patients limits their clinical application.