A radioluminescent compound for radiotherapy and deep photodynamic therapy (Deep PDT), the radioluminescent compound including a molecular conjugate made up of a radioluminescent molecule and one photosensitizer, the radioluminescent molecule being suitable for absorbing an X-ray with energy higher than an absorption threshold and for emitting luminescent radiation in the visible domain, and the photosensitizer being suitable for absorbing the luminescent radiation and producing singlet oxygen. The radioluminescent compound is made up of a molecule of lanthanide chloride (LnCl3)； the photosensitizer is selected among the following photosensitizers: Al(III)Phthalocyanine, mTHPC, chlorin e6 (Ce6), hypericin, hypocrellin, Nile blue, Oxazine 170, Oxazine 1, Protoporphyrin IX, 7-methoxycoumarin-4-acetic acid, bacteriochlorophyll, and auramin； and the photosensitizer is selected such as to maximize the energy transfer between an X-ray absorbed by the radioluminescent lanthanide 2 and the photosensitizer in order to produce singlet oxygen.
