High resolution 3D imaging of synchrotron generated microbeams.

Area of Science:

• Medical physics
• Radiation oncology
• Imaging science

Background:

• Microbeam radiation therapy (MRT) shows promise in preclinical studies.
• Advancing MRT to human clinical trials requires precise dosimetry and beam verification.
• Synchrotron-based MRT offers unique irradiation capabilities.

Purpose of the Study:

• To demonstrate high-resolution 3D imaging of synchrotron-generated microbeams.
• To utilize PRESAGE® dosimeters for MRT characterization.
• To validate laser fluorescence confocal microscopy for MRT verification.

Main Methods:

• Fabrication and irradiation of water-equivalent PRESAGE® dosimeters with synchrotron microbeams.
• Delivery of various microbeam array configurations (single, cross-fire, multidirectional, interspersed).
• High-resolution imaging using a Nikon A1 laser fluorescence confocal microscope.

Main Results:

• Clear visualization of microbeam spatial fractionation in 2D and up to 9 mm depth.
• Resolution of individual microbeams with measurements as low as 0.09 μm/pixel.
• Measurement of peak-to-valley dose ratios and sample positioning variations.

Conclusions:

• Laser fluorescence confocal microscopy is a validated high-resolution imaging technique for PRESAGE® dosimeters.
• This method allows independent spatial and geometrical verification of MRT beam delivery.
• The findings support the progression of MRT towards clinical applications.