Patent ID: 8598546

Claim:
A method of generating a data set defining a plurality of target points in a target volume in a body at which a particle beam is to be directed in a continuous or discontinuous process, so as to provide a spatial dose distribution in an area around the respective target points, each of the target points having a z-spacing from an adjacent target point, and a respective spacing from an adjacent target point in a direction perpendicular to the direction of the particle beam, the method comprising: defining the target points in the data set by the following parameters: z-spacing, the z-spacing being a distance, measured in a direction of the particle beam in a homogenous body equivalent to the body, between the respective target point and an adjacent target point at different depth corresponding to a higher or lower particle energy, respective spacing in a direction perpendicular to the direction of the particle beam, and the spatial dose distribution, wherein at least one of the parameters is varied throughout the data set in dependence upon a particle energy of the target points.