Protons and CPT

Question 1

Why do protons behave differently?

Answer 1

• heavy ions
• higher RBE than photons
• High LET
• Range uncertainty, question around RBE
• Sharp increase in dose at specific depth
• Rapid dose fall off
• no bremsstrahlung tail

Question 2

What are some disadvantages of using charged particle therapy?

Answer 2

• High energy needed (expensive)
• Choice of cyclotron and synchrotron
• Uses a lot of space
• Gantry system is very heavy

Question 3

What developments are being made in charged particle therapy?

Answer 3

• Cost will come down through economy of scale, more centres = reduced development and maintanence
• More flexible treatment and delivery verification (in room CBCT and kV monitoring)
• Improved beam generators, more efficient at high energies
• More compact machines
• Linacs?