Revision 1

Accepted · first revision · record

Title: Optimal beam width and spacing scaling law
Plain: Choosing stripe width and gap is currently trial and error. A rule connecting them to tissue type and depth is missing.
Precise: Derive a scaling relation for the therapeutic ratio as a function of beam width w, centre-to-centre spacing s, and depth, including beam broadening by multiple scattering for protons and by scattered photons for x-rays, so that the pattern merges into a uniform field at the target while staying fractionated in normal tissue. An answer is a design rule for w and s with the physical quantities that set them.
Settled by: Measured dose profiles at depth combined with tolerance data across several geometries, showing a single relation that predicts the optimum.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: open
Status note: (empty)
Posed since: 2010