Measuring radioenhancement by gold nanofilms: Comparison with analytical calculations.

Phys Med

Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, South Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul 03080, South Korea; Robotics Researc

Published: December 2019


Category Ranking

98%

Total Visits

921

Avg Visit Duration

2 minutes

Citations

20

Article Abstract

Purpose: To measure radioenhancement by gold nanoparticles (GNPs) using gold nanofilms (GNFs).

Methods: GNFs of 20-100 nm thicknesses were prepared. The GNF attached to radiochromic film (RCF) was irradiated using 50, 220 kVp, and 6 MV X-rays. The radiation doses to the active layer of RCF with and without GNF were measured using an optical flatbed scanner and Raman spectrometer to estimate the dose enhancement factor (DEF). For verification, analytical calculations of DEF within the thickness of active layer and the ranges of secondary electrons were carried out.

Results: The DEFs for GNFs of 20 to 100 nm thicknesses measured by an optical scanner ranged from 2.1 to 6.1 at 50 kVp and 1.6 to 4.9 at 220 kVp. Similarly, the DEFs measured by Raman spectroscopy ranged from 2.6 to 4.6 at 50 kVp and 2.2 to 4.8 at 220 kVp. The calculated DEFs ranged from 1.5 to 3.6 at 50 kVp and from 1.7 to 4.7 at 220 kVp. Almost no dose enhancement was observed in 6 MV X-ray. The analytical DEFs seemed to be underestimated by averaging local enhancement over the entire active layer. However, analytical DEFs within the ranges of secondary electrons was much higher than the measured macroscopic DEFs.

Conclusions: The experimental and analytical approaches developed in this study could quantitatively estimate radioenhancement by GNPs. Due to a short range of low-energy electrons emitted from gold, the microscopic radioenhancement within the ranges of low-energy electrons would be particularly important in a cell.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2019.10.040DOI Listing

Publication Analysis

Top Keywords

active layer
12
ranged 50 kvp
12
50 kvp 220 kvp
12
radioenhancement gold
8
gold nanofilms
8
analytical calculations
8
measured optical
8
dose enhancement
8
ranges secondary
8
secondary electrons
8

Similar Publications

Background: Velocity-Based Training (VBT) is an emerging method in resistance training for objectively prescribing and monitoring training intensity and neuromuscular function. Given its growing popularity, assessing the validity and reliability of VBT devices is critical for strength and conditioning coaches.

Objective: The primary purpose of this review was twofold: (1) to identify and address methodological gaps in current assessments of VBT device validity and reliability, and (2) to propose and apply a novel, multi-layered, criterion-based framework-developed in collaboration with statisticians and domain experts-for evaluating these devices.

View Article and Find Full Text PDF

The claustrum (CLA) is a thin and elongated brain structure that is located between the insula and lateral striatum and is implicated in a wide range of behaviors. It is characterized by its extensive synaptic connectivity with multiple cortical regions. While CLA projection neurons are glutamatergic, several studies have shown an inhibitory impact of CLA on its cortical targets, suggesting the involvement of inhibitory cortical interneurons.

View Article and Find Full Text PDF

Terminalia arjuna, an important medicinal plant in traditional Indian systems, has been extensively studied for its cardioprotective bark. However, limited attention has been given to its fruit, which contains several biologically active phytochemicals with potential antioxidant, anti-inflammatory, and immunomodulatory properties. This study aimed to isolate and partially purify phytoactive compounds from the fruit of T.

View Article and Find Full Text PDF

The FtsEX-EnvC-AmiA/B system is a key component of the cell division machinery that directs breakage of the peptidoglycan layer during separation of daughter cells. Structural and mechanistic studies have shown that ATP binding by FtsEX in the cytoplasm drives periplasmic conformational changes in EnvC, which lead to the binding and activation of peptidoglycan amidases such as AmiA and AmiB. The FtsEX-EnvC amidase system is highly regulated to prevent cell lysis with at least two separate layers of autoinhibition that must be relieved to initiate peptidoglycan hydrolysis during division.

View Article and Find Full Text PDF

Cation Dehydration by Surface-Grafted Phenyl Groups for Enhanced C Production in Cu-Catalyzed Electrochemical CO Reduction.

J Am Chem Soc

September 2025

Laboratory of Inorganic Synthesis and Catalysis (LSCI), Institute of Chemical Sciences and Engineering, École Polytechnique Fédéralede Lausanne (EPFL), Lausanne 1015, Switzerland.

The challenge to produce multicarbon (C) products in high current densities in the electrochemical reduction of carbon dioxide (CORR) has motivated intense research. However, the ability of solvated cations to tune and activate water for C production in the CORR has been overlooked. In this study, we report the incorporation of a covalently grown layer of functionalized phenyl groups on the Cu surface that leads to a 7-fold increase in ethylene production (to -530 mA cm) and a 6-fold increase in C products (to -760 mA cm).

View Article and Find Full Text PDF