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Measurement of Stray Radiation Around a Mobile Electron Accelerator for Intraoperative Radiotherapy

H Liu

H Liu1*, (1) Fudan University, Shanghai,


SU-I-GPD-T-632 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: The aim of this study is to measure the stray radiation distribution characteristics around the mobile electron accelerator for intraoperative radiotherapy(IORT).

Methods: In this study, the three-dimensional tray X-ray distribution of the intraoperative radiotherapy electron accelerator was measured and characterized by means of thermoluminescence dosimeters (TLDs). Three TLDs were placed in a transparent silicone tube and numbered after annealing, and each tube was fixed to a representative space point by thread. Different electron beam energy includes 4MeV,6MeV,9MeV,1 MeV 4 were investigated in this study, and the accelerator delivered dose of 10Gy at the dose rate of 10Gy / min for each measurement.

Results: The averaged dose equivalents at 50cm, 100cm, 150cm and 200cm from the center axis were 1690uSv, 7.56uSv, 395uSv and 241uSv, respectively; the maximum difference between the dose and the mean value at the different angles of 50cm from the center reference point is 9.1%, indicating that the radiation field distribution conformed to the angle symmetry.The averaged dose equivalents were 527μSv, 756μSv, 570μSv and 141μSv, on the height plane at 50cm, 100cm, 150cm and 200cm respectively. And on 100cm height plan, the averaged dose equivalents the doses of 4MeV, 6MeV, 9MeV and 12MeV electron beam energy at 100cm from the center axis of were 57.3μSv,486μSv, 689μSv and 781μSv, respectively, the increase of the beam energy increases the production of the secondary radiation.

Conclusion: The doses of the same height plane were exponentially decreasing with the distance from the center axis increasing. The dose distribution is basically similar for lines of different angle, and angle symmetry was observed on the same height plan. The 100cm height plane which is closest to the electrons interact position, got the largest values among different height planes. For different investigated electron energy, secondary radiation increased with the increase of electron energy.

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