Absorbed dose uncertainty evaluation in proton therapy of prostate cancer by Monte Carlo method

Document Type : Conference Paper

Authors

1 Department of Physics, Isfahan University of Technology, Isfahan, Iran

2 Department of Biomedical Engineering, University of Isfahan, Isfahan, Iran

3 Department of Physics, Isfahan University of Technology, Isfahan, Iran.

Abstract

Proton therapy is one of the prostate cancer treatments. Bragg peak in proton depth-dose curve is the most important characteristic of this method. It causes the most amount deposition of energy in the tumor. Prostate is not a fixed organ and has involuntary movement in the range of 1-7mm due to bloating of the gastrointestinal tract in body, so this movement results in uncertainty in absorbed dose of particle. In this research absorbed dose are calculated regarding prostate movement using FLUKA code which works with Monte Carlo method. First, the phantom used is simulated. Regarding depth of 15cm of prostate in body the needed energy to form Bragg peak in tumor was calculated 148 MeV with 0.02% precision. Total Absorbed dose for one proton particle is 7.2 nGy when prostate was considered fixed in coordinate center .it was shown that 99.9% of total absorbed dose which is deposited in prostate and does not damage other tissues. The reason for this is the presence of Bragg Peak, which is all the energy absorbed in this area. with moving prostate for 7mm in perpendicular proton beam direction, the total dose absorbed by the prostate is reduced by 2.2%, also for moving prostate in line with proton beam, the total dose absorbed by the prostate is reduced by 6.66%.

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References

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