Series review of radioembolization with yttrium: 90 microspheres (Part IV): dose calculation of yttrium-90 microspheres

Accurate doses of yttrium-90 (⁹⁰Y) microspheres are critical for the treatment of liver malignancies, because it is closely related to the clinical efficacy and adverse reactions. The dose calculation is primarily based on the type of ⁹⁰Y delivery medium, whether it is glass microsphere (Thera Spheres) or resin microsphere (SIR-Spheres). The dose calculation of glass microspheres is based on the assumption that the expected radiation dose of the liver and the microspheres can be evenly distributed throughout the liver, while the dose calculation of resin microspheres is based on the assumption that the microspheres are not uniformly distributed throughout the liver, and the degree of this inhomogeneous distribution depends on the extent to which the normal liver is replaced by the tumor tissue. Many other factors may also potentially affect the therapeutic dose of ⁹⁰Y microspheres. This review will introduce the calculation methods of ⁹⁰Y microsphere dose, and describe the factors that need to be considered in order to achieve maximum efficacy and avoid adverse effects. (authors)