Abstract: Objective To study the dose distribution of different bolus after different energy electron beam irradiation to different chest wall radiotherapy for the patients with breast cancer. Methods The paper simulated the dose distribution of women's left breast cancer after radical mastectomy by 6 and 9MeV electron beam irradiation, and TLD was used to measure. Results The dose of skin became higher and the dose of lung was less when 0.5 and 1.0 cm bolus were used on the body；with the increasing of the energy of electron beam, the high dose field became larger；and with the same energy of electron beam, the high dose field moved to surface of the body when the bolus was thicker.Conclusion When different energy electron ray irradiates different thickness bolus ,the dosage of skin surface increases and the dosage of anterior margin of lung reduces. With electron ray energy increasing ,the high dosage field is widen ,when the electron ray energy is identity ,the high dosage field migrates to the surface after adding bolus.Using certain depth bolus may attain the therapeutical dose of target area.

Key words: radiotherapy, radiation dose , high dose field