Sensitivity enhancement of DHR123 radio-fluorogenic nanoclay gel dosimeter by incorporating surfactants and halogenides

Anri Mochizuki,Yusuke Watanabe,Takuya Maeyama,Shinya Mizukami

doi:10.1039/d0ra02717k

Anri Mochizuki, Yusuke Watanabe + Show 2 more

Open Access

https://doi.org/10.1039/d0ra02717k

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Abstract

Dosimetry of spatial dose distribution of ionizing radiation in tissue equivalent materials is particularly important for cancer radiotherapy. Here, we describe a radio-fluorogenic gel-based dosimeter that has achieved 16 times higher sensitivity by incorporating surfactants and halogenides. The gel dosimeters were prepared from dihydrorhodamine 123 (DHR123) and small amounts of nano-sized clay and a radiosensitizer. By comprehensively changing the type of additives for the sensitizer (three surfactants: Triton X-100, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide, and three halogenides: trichloroacetic acid, tribromoacetic acid and 2,2,2-trichloroethanol), the increase in sensitivity can be explained by an increase in relative fluorescence quantum yield and an increase in radiation chemical yield. These highly sensitive gel dosimeters also show dose rate independent sensitivity under irradiation at 0.64 and 0.77 Gy min−1 using a 6 MV X-ray therapeutic beam from the medical linac.

Highlights

In cancer radiotherapy, a three-dimensional (3D) dose distribution is adjusted to the shape of a tumor
The Dihydrorhodamine 123 (DHR123) probe was applied to ionizing radiation dosimeter,[5] since this DHR123 probe work for ionizing radiation induced reactive oxidizing species (ROS).[6]
While the uorescence distribution corresponding to dose distribution was maintained in the hydro nano-clay gel matrix, DHR123 radio- uorogenic nano-clay gel (DHR123RFG) dosimeter produced twodimensional (2D) dosimetry with a 2D uorescent scanner

Summary

Introduction

A three-dimensional (3D) dose distribution is adjusted to the shape of a tumor. High-precision radiotherapy that focuses high doses of radiation on tumors and decreases the amount of damage to healthy tissues is performed. To validate the complex dose distribution, a dosimetry is required that is tissue equivalent and has high spatial resolution in three dimensions.[1,2,3]. The DHR123 probe was applied to ionizing radiation dosimeter,[5] since this DHR123 probe work for ionizing radiation induced ROS.[6] The uorescence intensity increases with the increase in the absorbed dose. While the uorescence distribution corresponding to dose distribution was maintained in the hydro nano-clay gel matrix, DHR123 radio- uorogenic nano-clay gel (DHR123RFG) dosimeter produced twodimensional (2D) dosimetry with a 2D uorescent scanner

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