# Radiation-Sensitive Nano-, Micro-, and Macro-Gels and Polymer Capsules for Use in Radiotherapy Dosimetry

## TL;DR

This paper introduces a new method for creating radiation-sensitive gels and capsules for measuring radiation doses in cancer treatments.

## Contribution

The novelty lies in using Fricke solution and ionic polymer reactions to create 1D, 2D, and 3D dosimeters with varying gel structures.

## Key findings

- Nano- and micro-gels can be used to create 2D or 3D dosimeters by infusing a physical gel matrix.
- Macro-gels and capsules with Fe ions can serve as 3D and 1D dosimeters, respectively.
- The critical polymer concentration (c*) determines the type of gel structure formed.

## Abstract

This work introduces an original approach to the manufacturing of ionizing radiation-sensitive systems for radiotherapy applications—dosimetry. They are based on the Fricke dosimetric solution and the formation of macro-gels and capsules, and nano- and micro-gels. The reaction of ionic polymers, such as sodium alginate, with Fe and Ca metal ions is employed. Critical polymer concentration (c*) is taken as the criterion. Reaction of ionic polymers with metal ions leads to products related to c*. Well below c*, nano- and micro-gels may form. Above c*, macro-gels and capsules can be prepared. Nano- and micro-gels containing Fe in the composition can be used for infusion of a physical gel matrix to prepare 2D or 3D dosimeters. In turn, macro-gels can be formed with Fe ions crosslinking polymer chains to obtain radiation-sensitive hydrogels, so-called from wall-to-wall, serving as 3D dosimeters. The encapsulation process can lead to capsules with Fe ions serving as 1D dosimeters. This work presents the concept of manufacturing various gel structures, their main features and manufacturing challenges. It proposes new directions of research towards novel dosimeters.