Patent ID: 8897857

Claim:
A proton therapy treatment program stored in a non-transitory computer-readable storage medium executable on an electronic computer to perform the steps of: (a) receiving photon attenuation data of a patient based on attenuation of x-ray photons passing through patient tissue; (b) segmenting the received photon attenuation data into at least two tissue types; (c) receiving a first proton projection value for a proton beamlet passing through a first of the at least two tissue types of the patient tissue while avoiding a second of the at least two tissue types, and receiving a second proton projection value for a proton beamlet passing through the first and the second of the at least two tissue types; (d) converting at least a portion of the photon attenuation data to derived proton stopping-power data using first and second conversion functions unique to the first and the second tissue types, wherein the first conversion function is based on the first proton projection value, and the second conversion function is based on the second proton projection value modified by the first conversion function; and (e) producing a treatment control sequence defining proton energies along different paths through the patient tissue using the derived proton stopping power data according to a predefined treatment plan.