Partial-Volume Irradiation of Murine Tumors.

Radiotherapy is a widely used approach for cancer treatment. However, delivering a single high dose of radiation to bulky tumors can be challenging due to the toxicities induced in the surrounding healthy tissue. To overcome this issue, a nonuniform high dose can be delivered using partial-volume tumor irradiation or spatially fractionated radiotherapy (SFRT). Moreover, SFRT has the potential to induce a stronger antitumor immune response compared to traditional radiotherapy due to the preservation of immune cells in the unirradiated tumor regions. There are several SFRT approaches, including GRID therapy, three-dimensional GRID therapy (LATTICE), microbeam radiation therapy (MRT), and Stereotactic Body Radiation Therapy for PArtial Tumor irradiation targeting exclusively the HYpoxic segment (SBRT-PATHY). The following protocol describes partial-volume tumor irradiation, a technique that enables dose delivery to only a part of the tumor in mice using an X-ray generator and collimators of different dimensions that limit the size of the irradiation field.