Nanoparticles having radially-oriented pores are fabricated from a noble metal. The pores have a specific geometrical shape, such as a circle, triangle, hexagon or other polygon. The nanoparticles are administered to a subject to form a nanoparticle-loaded tumor, which is targeted with a radiation beam as part of a radiotherapeutic treatment. The pores redirect photons of the radiation beam to intensify and enhance the dose received by tumor cells, while concomitantly reducing the dose received by surrounding cells and/or tissues. The nanoparticles may be combined with a radiosensitizing drug or agent, administered together or separately, to form a dose-enhancement composition that further intensifies the received dose of radiation at the target.