Radiation treatment planning that considers the dimensions of volumes in a treatment target

A non-transitory computer-readable storage medium storing computer-executable instructions that, when executed by a processor of a computer system, cause the computer system to perform a method for planning radiation treatment, the radiation treatment including spot scanning of a treatment target, and the method including

• accessing a representation of the treatment target in which the treatment target is separated into at least a first region and a second region, a first area of the first region being different from a second area of the second region,
• determining a first pattern of first spots inside the first region, a density of the first spots in the first pattern being based on the first area,
• determining a second pattern of second spots inside the second region, a density of the second spots in the second pattern being based on the second area, and
• storing, in a memory, the first pattern and the second pattern for access by a radiotherapy machine configured to perform the spot scanning of the treatment target based on a radiation treatment plan, the radiation treatment plan being based on the first pattern and the second pattern.

A computer-implemented method for planning radiation treatment, the radiation treatment including spot scanning of a treatment target, and the computer-implemented method comprising:

• accessing a description of the treatment target according to which the treatment target is virtually separated into at least a first region and a second region, first physical dimensions of the first region being different from second physical dimensions of the second region;
• determining a first density of first spots inside the first region based on the first physical dimensions;
• determining a second density of second spots inside the second region based on the second physical dimensions, the second density being different from the first density;
• determining a first pattern for the first spots in the first region, the first spots in the first pattern having at least the first density;
• determining a second pattern for the second spots in the second region, the second spots in the second pattern having at least the second density;
• and
• storing, in a memory, the first pattern and the second pattern for access by a radiotherapy machine configured to perform the spot scanning of the treatment target based on a radiation treatment plan, the radiation treatment plan being based on the first pattern and the second pattern.