Revision 1

Accepted · first revision · record

Title: Patient stopping-power accuracy below one percent
Plain: The plan converts a CT scan into a map of how fast particles slow down. Converting image numbers into that map introduces an error of a few percent, which becomes a few millimetres of range error.
Precise: Determine the stopping power of patient tissues relative to water from imaging to better than 1 percent root-mean-square, including tissue mean excitation energies relative to water and tissue-composition variability. Candidate routes: dual-energy CT, photon-counting spectral CT, proton CT. An answer is a validated conversion with a stated uncertainty budget.
Settled by: Direct proton-beam measurement of stopping power in tissue samples and phantoms compared against the imaging-derived map.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: partially-resolved
Status note: Dual-energy CT lowered relative stopping-power errors to roughly 1 percent by 2023; tissue I-values and tissue-composition variability remain the dominant residual terms.
Posed since: 1996