Biomedical imaging is an essential tool for diagnosis and
therapy of diseases such as
cancers. It is likely true that medicine has developed with biomedical imaging methods. Sensitivity and resolution of biomedical imaging methods can be improved with imaging agents. Furthermore, it will be ideal if imaging agents could be also used as therapeutic agents. Therefore, one dose can be used for both diagnosis and
therapy of diseases (i.e., theragnosis). This will simplify medical treatment of diseases, and will be also a benefit to patients. Mixed (Ln(1x)Ln(2y)O3, x + y = 2) or unmixed (Ln2O3)
lanthanide (Ln)
oxide nanoparticles (Ln = Eu, Gd, Dy, Tb, Ho, Er) are potential multi-modal imaging and
cancer therapeutic agents. The
lanthanides have a variety of magnetic and optical properties, useful for magnetic resonance imaging (MRI) and fluorescent imaging (FI), respectively. They also highly attenuate X-ray beam, useful for X-ray computed tomography (CT). In addition
gadolinium-157 ((157)Gd) has the highest thermal neutron capture cross section among stable
radionuclides, useful for
gadolinium neutron capture therapy (GdNCT). Therefore, mixed or unmixed
lanthanide oxide nanoparticles can be used for multi-modal imaging methods (i.e., MRI-FI, MRI-CT, CT-FI, and MRICT- FI) and
cancer therapy (i.e., GdNCT). Since mixed or unmixed
lanthanide oxide nanoparticles are single-phase and solid-state, they can be easily synthesized, and are compact and robust, which will be beneficial to biomedical applications. In this review physical properties of the
lanthanides, synthesis, characterizations, multi-modal imagings, and
cancer therapy of mixed and unmixed
lanthanide oxide nanoparticles are discussed.