Laser Accelerated Proton Beams for
Radiation Therapy
C-M Ma, T Tajima, B Shahine, JS Li,
MC Lee, T Guerrero and AL Boyer
Dept. of Radiation Oncology
Stanford University School of Medicine
Stanford, CA 94305, USA
Why/Why Not Proton Beams?

Advantageous dosimetry
characteristics

Expensive, cumbersome,
inflexible

Potential remains to be
explored
Laser Ion Acceleration
q = 0.6 degrees
Computational and experimental proton acceleration
as a function of laser intensity (Zhidkov et al. 1999).
Theoretical Results
Particle in cell (PIC) simulation results (Ueshima 1999b) on ion and
electron acceleration by laser irradiation on three thin targets. A laser
intensity of 1021 W/cm2on the target surface is applied.
Energy conversion
Ion
Electron
Peak energy H+
Peak energy Al10+
Peak energy electron
Average energy H+
Average energy Al10+
Case 1
50%
4%
48%
200 MeV
1 GeV
25 MeV
58 MeV
130 MeV
Case 2
24%
8%
16%
400 MeV
2 GeV
15 MeV
95 MeV
500 MeV
Case 3
31%
14%
17%
400 MeV
2 GeV
20 MeV
115 MeV
500 MeV
Proton angular distribution
Proton spectrum
Energy Conversion and Dose Rate
Total laser energy delivered
on target per shot:
8J
Total proton energy
converted from laser
(above MeV)
1J
Total proton energy within
a therapeutic energy
window
0.01 – 0.1 J
Dose per laser shot
1 – 10 Gy
3.5E+5
3.0E+5
Energy (MeV)
2.5E+5
2.0E+5
1.5E +5
1.0E +5
5.0E+4
0.0E+0
0
5
10
15
20
25
D epth (cm )
30
35
40
Combined dose distribution
Proton spectrum
6.0E +4
1 .6
4.0E +4
Probability
Energy (MeV)
1 .2
0 .8
2.0E +4
0 .4
0 .0
0.0E +0
0
5
10
15
D epth (cm )
20
25
30
80
100
120
140
160
E n e rg y (M e V )
180
200
Comparison of Isodose Distribution
Photon IMRT
Modulated Proton beams
Comparison of DVH
Target DVH
Rectum DVH
Current Research at Stanford
on Laser-Proton Beams
 Particle-in-cell (PIC) simulations of laser-ion interactions
 System design for a laser-proton therapy unit
 Software development for accurate and fast dose
calculation
 Treatment optimization for energy-and intensitymodulated proton therapy (EIMPT)
For detailed dose calculation and IMPT treatment
optimization, please see:
 Jinsheng Li, et al., TU-C-BRA-06
 Bilal Shahine et al, TU-C-BRA-07
The Stanford Monte Carlo Team
Charlie Ma
Gary Luxton
David Findley
Todd Koumrian
Steve Jiang
Jinsheng Li
Eugene Fourkal
Michael Luxton
Michael Lee
Jasjit Jolly
Art Boyer
Todd Pawlicki
Ed Mok
Sam Brain
Thomas Guerrero
Jun Deng
Joerg Lehmann
Meisong Ding
Ajay Kapur
Grisel Mora