Mini-beam collimators for medical linear accelerators

A method for generating spatially fractionated radiation, the method comprising:

• generating an open radiation beam oriented along a beam axis and having photon energies up to and including a maximum photon energy, the maximum photon energy greater than 0.5 MV;
• positioning a mini-beam collimator in a path of the open radiation beam, the mini-beam collimator comprising a plurality of generally planar blades extending between an entrance aperture onto which the open beam impinges and an exit aperture,
• producing, by interaction of the mini-beam collimator with the open radiation beam, an output beam emitted from the exit aperture, oriented along the beam axis and comprising a spatially fractionated mini-beam dose profile, the spatially fractionated mini-beam dose profile comprising:
• a plurality of dose peaks at which the dose is a local maximum, the dose peaks spaced apart from one another in a transverse direction that is transverse to the beam axis;
• and
• a plurality of dose valleys at which the dose is a local minimum, each dose valley located between a pair of transversely adjacent dose peaks.

A method for treating a tumor in a patient using spatially fractionated radiation, the method comprising:

• generating an open radiation beam oriented along a beam axis and having photon energies up to and including a maximum photon energy, the maximum photon energy greater than 0.5 MV;
• positioning a mini-beam collimator in a path of the open radiation beam, the mini-beam collimator comprising a plurality of generally planar blades extending between an entrance aperture onto which the open beam impinges and an exit aperture,
• producing, by interaction of the mini-beam collimator with the open radiation beam, an output beam emitted from the exit aperture, oriented along the beam axis and comprising a spatially fractionated mini-beam dose profile, the spatially fractionated mini-beam dose profile comprising:
• a plurality of dose peaks at which the dose is a local maximum, the dose peaks spaced apart from one another in a transverse direction that is transverse to the beam axis;
• and
• a plurality of dose valleys at which the dose is a local minimum, each dose valley located between a pair of transversely adjacent dose peaks;
• and.
• locating the patient along the beam axis, so that the output beam impinges on the patient, thereby delivering the spatially fractionated mini-beam dose profile to the patient.