Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters

Area of Science:

• Medical Physics
• Polymer Chemistry
• Radiation Detection

Background:

• Polymer gel dosimeters offer 3D radiation dose distribution recording for medical applications.
• Post-irradiation diffusion of species in gels degrades dose information over time, especially in dose gradient regions.

Purpose of the Study:

• To develop a novel polymer gel dosimeter system to mitigate post-irradiation diffusion.
• To investigate the effects of monomer chemical structure modification on dosimetric sensitivity and diffusion.

Main Methods:

• Modified itaconic acid monomers (with aniline) and original itaconic acid were synthesized and incorporated into polymer gel dosimeters.
• Dosimeters were irradiated using X-ray tomography up to 173 Gy.
• Characterization involved Raman spectroscopy, optical absorbance, and optical-CT to analyze dosimetric properties and diffusion.

Main Results:

• The study explored how altering monomer molecular size affects dosimetric sensitivity and diffusion.
• Analysis confirmed the feasibility and capabilities of the modified itaconic acid-based dosimeters.
• Optical-CT was used to quantify post-irradiation diffusion within the gel systems.

Conclusions:

• The novel itaconic acid-based polymer gel dosimeters show promise for improved accuracy in 3D radiation dose measurement.
• Understanding and controlling diffusion is crucial for maintaining the integrity of dose information in polymer gel dosimetry.
• Chemical modification of monomers offers a viable strategy to enhance dosimeter performance.