The precision of proton therapy treatment is due to the Bragg peak. To exploit the Bragg peak, accuracy is needed.
Proton radiography and tomography will allow the exploitation of the Bragg peak providing enhanced imaging, reducing uncertainty and error associated relative stopping power, and eliminating the need to estimate relative biological effectiveness (RBE), resulting in improved treatment planning, verification, and treatment.
Additionally, proton radiography and tomography allows for faster positioning verification and reduced dose when imaging.1
Using CT scans, the systematic error range is between 3% and 5% for soft tissue and is higher for harder structures and tissues. Proton radiography and tomography could reduce range uncertainty to less than 1%.2
High proton energies are needed for proton radiography and tomography. To image any anatomical area a 330 MeV proton beam is needed.
With a clinical treatment energy range of 70-250 MeV and the ability to accelerate protons up to 330 MeV, Radiance 330 has the capability for proton imaging.
ProTom is developing a dual-purpose beamline, allowing for imaging and treatment with the same beam.
1 G Poludniowski, N M Allinson, P M Evans. “Proton radiography and tomography with application to proton therapy.” Br J Radiol. September 2015; 88(1053): 20150134. Published online 2015 Jul 1. doi: 10.1259/bjr.20150134 PMCID: PMC4743570
2 Elizabeth Allen. “World-first Proton CT images create a new vision for cancer treatment.” Phys.Org.
Published online 2017 May 11.