Characterization of a Low-Energy Cyclotron-Based Proton Beam for Preclinical Radiobiological Studies

Area of Science:

• Medical Physics
• Radiation Oncology
• Cell Biology

Background:

• Proton therapy offers advantages over conventional radiotherapy due to its precise dose distribution, sparing healthy tissues.
• Optimizing proton Relative Biological Effectiveness (RBE) is crucial for enhancing tumor control and minimizing side effects.
• Preclinical research is essential for advancing the clinical application of proton therapy.

Purpose of the Study:

• To optimize a low-energy cyclotron-based proton irradiation setup for in vitro radiobiological research.
• To establish a reliable dosimetry system for pulsed proton beams.
• To investigate the effects of proton irradiation on glioblastoma cell lines.

Main Methods:

• A cyclotron-based proton irradiation system was optimized for in vitro experiments.
• System dosimetry was assessed using Gafchromic EBT4 films and integrated beam charge.
• Pulsed dose rate measurements were performed, and glioblastoma cell lines (U373 and U87) were irradiated.
• Cell survival and DNA damage were quantified post-irradiation.

Main Results:

• Homogeneous dose profiles were achieved with 14 MeV protons over a 21 mm diameter area.
• A linear relationship was established between proton dose and integrated beam charge for pulsed dose rates (10.8-16.2 Gy/s).
• Proton irradiation of U373 cells showed comparable effects on cell survival to kilovoltage X-rays; U87 cells exhibited unrepaired DNA damage.

Conclusions:

• A cyclotron-based pulsed proton beam was successfully optimized for in vitro radiobiological research.
• The optimized system enables the evaluation of cell survival and DNA damage in glioblastoma models.
• This work contributes to the advancement of proton therapy research and optimization.