holmium-166 microspheres

Holmium-166 microspheres are radiopharmaceutical devices composed of the radioisotope holmium-166 embedded in poly-L-lactic acid (PLLA) particles. They are used for selective internal radiation therapy (SIRT), primarily to treat unresectable primary liver cancer and liver metastases. Upon intra-arterial administration into the hepatic artery, these microspheres deliver targeted beta radiation to tumor tissue while minimizing exposure to healthy tissue. Holmium-166 also emits gamma photons and has paramagnetic properties, enabling both SPECT and MRI imaging for precise dosimetry and treatment monitoring. The product was developed at University Medical Center Utrecht and is commercially available as QuiremSpheres (for therapy) and QuiremScout (for pre-treatment planning). The mechanism of action is local emission of beta particles that induce tumor cell death[1][2][3][4][5][6].

Brand names

QuiremSpheresQuiremScout

Other names

holmium Ho 166 poly(L-lactic acid) microspheres166Ho-QuiremSpheres