Confocal Laser Scanning Microscope Imaging of Custom-Made Multi-Cylinder Phantoms: Theory and Experiment

Area of Science:

• Optical microscopy
• Biomedical imaging
• Computational modeling

Background:

• Confocal laser scanning microscopy (CLSM) is crucial for high-resolution imaging.
• Accurate modeling of CLSM image formation is essential for quantitative analysis.
• Custom phantoms enable precise investigation of microscope performance.

Purpose of the Study:

• To investigate CLSM image formation using custom-made multi-cylinder phantoms.
• To validate a GPU-accelerated Monte Carlo (MC) software for CLSM simulations.
• To compare simulation results with experimental measurements across varying parameters.

Main Methods:

• Fabrication of multi-cylinder phantoms (5-10 μm radii) using 3D direct laser writing.
• CLSM measurements with varied refractive index differences and system parameters (pinhole size, NA).
• Development and application of a tetrahedron-based, GPU-accelerated MC software for simulating the confocal setup.

Main Results:

• High agreement between simulated and measured CLSM images for large refractive index differences (e.g., air).
• Good agreement observed even with low refractive index differences (down to 0.005) using immersion oil.
• MC simulations successfully reproduced key image features and penetration depth trends.

Conclusions:

• The developed MC software accurately models CLSM image formation for complex structures.
• The simulation approach is robust across a range of refractive index contrasts.
• This work provides a validated tool for enhancing CLSM quantitative imaging and analysis.