Table 2.
Comparison between X-ray, proton, and carbon-based radiotherapy.
| Parameter | Carbon Ions | Protons | X-ray |
|---|---|---|---|
| Year of First Treatment | 1994 | 1954 | Late 1800s and Early 1900s |
| Number of Sites Treating (Last Update: Sep 2020) | 12 | 97 | Routine |
| Worldwide treated patients, estimate | 30,000# | 190,000# | Millions |
| Volume of irradiated normal tissue | Smallest | Small | Large |
| Bragg-Peak | Present | Present | Absent |
| Estimated RBE | 1.1-5.0 | 1.1 | 1.0 |
| Relative LET | Highest | High | Low |
| Targeting precision | Highest | High | Low |
| In tumor tissue | High | Low | Low |
| In normal tissue | Low | Low | Low |
| Relative Risk of Secondary Malignancy | Low | Low | High |
| System cost | Highest | High | Low |
#Dates from Particle Therapy Co-Operative Group.