In　recent　years,　photodynamic　therapy　has　been　applied　in　cancer　treatment　because　of　its　high　selectivity　and　marginal　invasion　properties.　However,　the　excitation　light　used　has　limited　ability　to　penetrate　tissue,　which　creates　a　stumbling　block　for　its　future　development.　To　overcome　this,　X-rays　have　been　introduced　to　transmit　energy　to　deeper　tissues.　Given　that　a　large　number　of　X-ray-induced　sensitizers　have　been　designed　to　facilitate　X-ray　excitation　and　generate　reactive　oxygen　species　(ROS),　this　has　led　to　the　concept　of　X-ray-induced　photodynamic　therapy　(X-PDT).　After　10　years　of　development,　this　treatment　now　shows　good　therapeutic　effects　as　well　as　shortcomings.　Going　forward,　it　will　be　important　to　improve　tumor　targeting　and　a　standard　deep-seated　tumor　model　should　be　established.　©　2018　Elsevier　Ltd