In this study, a high-performance T-1-T-2 dual-model contrast agent by gadolinium-doped iron oxide nanoparticle (GION) is developed. Following its development, the application of this agent in vivo by combining doxorubicin (DOX) and folic acid (FA) (FA-GION-DOX) for targeted drug delivery to monitor cancer treatment is explored. GION showed transverse and longitudinal relaxivities up to 182.7 x 10(-3) and 7.87 x 10(-3)m(-1) s(-1), respectively, upon Gd/Fe ratio in GION at 1/4. DOX released from FA-GION-DOX is pH dependent and only kills cancer cell after FA receptor-mediated internalization into the acidic environment of endosomes and lysosomes. Systemic delivery of FA-GION-DOX significantly inhibits the growth of tumors and shows good magnetic resonance enhancement in a human cervical cancer xenograft model. Thus, FA-GION-DOX has a potential application for the targeted and magnetic resonance imaging guided therapy of cervical cancer.