Fluorescent nuclear track detectors for alpha radiation microdosimetry

Area of Science:

• Radiation biology
• Nuclear medicine
• Cellular biophysics

Background:

• Alpha microdosimetry is crucial for understanding localized energy deposition effects.
• Traditional simulation-based methods present challenges in simplicity and reliability.
• A novel experimental approach using Fluorescent Nuclear Track Detectors (FNTD) was developed to improve accuracy and ease of use.

Purpose of the Study:

• To introduce and validate a novel experimental alpha microdosimetry technique.
• To assess the impact of alpha particle dose distribution within U87 glioblastoma cells.
• To compare experimental findings with simulation-based approaches.

Main Methods:

• Irradiation of FNTD and U87 glioblastoma cells using an external Americium-241 alpha source.
• Utilizing FNTD to measure alpha particle tracks and high-resolution 3D cell images for nucleus dose distribution calculation.
• Applying experimental microdosimetry parameters to simulations of 3D cell cultures with varying isotope distributions.

Main Results:

• The experimental method demonstrated good agreement with analytical nucleus dose distributions.
• A substantial increase in relative effectiveness (33-51%) was observed for isotopes located in the nucleus or on the nuclear membrane.
• Minor differences (<5%) in relative effectiveness were found for isotopes in the cytoplasm or on the cell membrane compared to external irradiation.

Conclusions:

• The FNTD-based experimental method is superior to simulation-based microdosimetry due to its accuracy and use of experimental data.
• Microdosimetry benefits are most significant for alpha radionuclide carriers that penetrate or surround the cell nucleus.
• Further research is needed considering in-vivo/in-vitro uncertainties and biological factors like relative biological effectiveness and oxygen enhancement ratio.