Improved Dose Response of N-(hydroxymethyl)acrylamide Gel Dosimeter with Calcium Chloride for Radiotherapy.

Khalid A Rabaeh,Molham M Eyadeh,Moneeb T M Shatnawi,Rawan E Al-Tarawneh,Issra’ M E Hammoudeh

doi:10.3390/gels8020078

Abstract

The impact of calcium chloride (CaCl2) on the performance of N-(hydroxymethyl)acrylamide (NHMA) polymer gel dosimeter is studied in this article. The dosimeter was exposed to doses of up to 10 Gy with radiation beam-energy of 10 MV and dose-rates of 300 cGy/min. The relaxation rate (R2) parameter was utilized to explore the performance of irradiated NHMAGAT gels. The dose response in terms of R2 increased from 0.29 to 0.63 Gy−1·s−1 with increasing calcium chloride concentration from 0 to 1000 mM. The results show no substantial impact of dose-rates as well as radiation energies on NHMAGAT samples. For the steadiness of irradiated NHMAGAT dosimeters, it was found that there is no apparent variation in R2 (less than ±3%; standard deviation) up to 3 days. The overall uncertainty of the gel dosimeter with calcium chloride is 4.96% (double standard deviation, 95% confidence level).

Highlights

New developments in radiotherapy have been concerned with the study of equivalent gel dosimeters for tissues containing active chemical sensors to measure the absorbed radiation dose [1,2,3,4,5,6]
Gel dosimeters such as polymer gels have a range of properties like biological tissues, and are suitable alternatives compared with conventional dosimeters due to their ability in resolving three-dimensional (3D) dose distributions [7,8,9,10,11]
The complex radiation dose response recorded in polymer gels can be explored in 3D utilizing various modalities such as MRI and optical techniques [18,19,20]

Summary

Introduction

New developments in radiotherapy have been concerned with the study of equivalent gel dosimeters for tissues containing active chemical sensors to measure the absorbed radiation dose [1,2,3,4,5,6]. The interaction between monomers in the gel after irradiation leads to drops in the mobility of H2 O molecules and decreases in the relaxation time (T2 ) values in the MRI technique [21,22,23,24]. These alterations of the transverse relaxation rate (R2 = 1/T2 )

Methods

Results

Conclusion