A method of measuring gold nanoparticle concentrations by x‐ray fluorescence for biomedical applications

Wu, Di; Li, Yuhua; Wong, Molly D.; Liu, Hong

doi:10.1118/1.4798966

Cited by 23 publications

(9 citation statements)

References 20 publications

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“…The experimental method provides an efficient way to obtain the fluorescence-only spectra through subtracting the water-spectra [6,7]. To convert the number of counts under the fluorescence peaks to GNP concentrations, energy windows need to be defined for each gold fluorescence peak.…”

Section: Experimentally Background Subtraction and Energy Window Detementioning

confidence: 99%

Background estimation methods for quantitative x-ray fluorescence analysis of gold nanoparticles in biomedical applications

Ren

et al. 2014

SPIE Proceedings

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Accurate background estimation to isolate the fluorescence signals is an important issue for quantitative X-ray fluorescence (XRF) analysis of gold nanoparticles (GNPs). Though a good estimation can be obtained experimentally through acquiring the background spectrum of water solution, it inevitably leads to unnecessary second exposure in reality. Thus, several numerical methods such as trapezoidal shape estimation, interpolation by polynomial fitting and SNIP (Statistics sensitive Nonlinear Iterative Peak-Clipping) algorithm are proposed to achieve this goal. This paper aims to evaluate the estimation results calculated by these numerical methods through comparing with that acquired using the experimental way, in term of mean squared error (MSE). Four GNP/water solutions with various concentrations from 0.0% to 1.0% by weight are prepared. Then, ten spectra are acquired for each solution for further analysis, under the identical condition of using pencil beam x-ray and single spectrometer. Finally, the experimental and numerical methods are performed on these spectra within the optimally determined energy window and their statistical characteristics are analyzed and compared. These numerical background estimation methods as well as the evaluation methods can be easily extended to analyze the fluorescence signals of other nanoparticle biomarkers such as gadolinium, platinum and Barium in multiple biomedical applications.

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Section: Experimentally Background Subtraction and Energy Window Detementioning

confidence: 99%

Background estimation methods for quantitative x-ray fluorescence analysis of gold nanoparticles in biomedical applications

Ren

et al. 2014

SPIE Proceedings

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“…6 In addition to research effort to fully elucidate the underlying physical, chemical, and biological mechanisms of GNPmediated radiosensitization, the development of a noninvasive imaging tool for monitoring the distribution of GNPs in vivo is also critical for a successful translation of GNPmediated radiosensitization strategies into clinical practices. In recent years, several imaging modalities, such as x-ray fluorescence imaging or computed tomography (XFCT) [26][27][28][29][30][31][32][33][34][35] and photoacoustic imaging, [36][37][38][39][40][41] have been suggested for this purpose and are currently under active development. While promising, these approaches need to be developed further, especially in terms of their applicability to human imaging applications.…”

Section: Introductionmentioning

confidence: 99%

Development of bimetallic (Zn@Au) nanoparticles as potential PET-imageable radiosensitizers

et al. 2016

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Purpose: Gold nanoparticles (GNPs) are being investigated actively for various applications in cancer diagnosis and therapy. As an effort to improve the imaging of GNPs in vivo, the authors developed bimetallic hybrid Zn@Au NPs with zinc cores and gold shells, aiming to render them in vivo visibility through positron emission tomography (PET) after the proton activation of the zinc core as well as capability to induce radiosensitization through the secondary electrons produced from the gold shell when irradiated by various radiation sources. Methods: Nearly spherical zinc NPs (∼5-nm diameter) were synthesized and then coated with a ∼4.25-nm gold layer to make Zn@Au NPs (∼13.5-nm total diameter). 28.6 mg of these Zn@Au NPs was deposited (∼100 µm thick) on a thin cellulose target and placed in an aluminum target holder and subsequently irradiated with 14.15-MeV protons from a GE PETtrace cyclotron with 5-µA current for 5 min. After irradiation, the cellulose matrix with the NPs was placed in a dose calibrator to assess the induced radioactivity. The same procedure was repeated with 8-MeV protons. Gamma ray spectroscopy using an high-purity germanium detector was conducted on a very small fraction (<1 mg) of the irradiated NPs for each proton energy. In addition to experimental measurements, Monte Carlo simulations were also performed with radioactive Zn@Au NPs and solid GNPs of the same size irradiated with 160-MeV protons and 250-kVp x-rays. Results: The authors measured 168 µCi of activity 32 min after the end of bombardment for the 14.15-MeV proton energy sample using the 66 Ga setting on a dose calibrator; activity decreased to 2 µCi over a 24-h period. For the 8-MeV proton energy sample, PET imaging was additionally performed for 5 min after a 12-h delay. A 12-h gamma ray spectrum showed strong peaks at 511 keV (2.05 × 10 6 counts) with several other peaks of smaller magnitude for each proton energy sample. PET imaging showed strong PET signals from mostly decaying 66 Ga. The Monte Carlo results showed that radioactive Zn@Au NPs and solid GNPs provided similar characteristics in terms of their secondary electron spectra when irradiated. Conclusions: The Zn@Au NPs developed in this investigation have the potential to be used as PET-imageable radiosensitizers for radiotherapy applications as well as PET tracers for molecular imaging applications. C

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“…X-ray fluorescence (XRF) based techniques capable of identifying and quantifying molecular imaging probes have been proposed [6,7]. Its basic physical principle relies on detecting the emissions of characteristic (fluorescent) x-rays from the imaging probes following excitation by high-energy x-rays or gamma rays.…”

Section: Introductionmentioning

confidence: 99%

Detection of posteriorly located breast tumors using gold nanoparticles: A breast-mimicking phantom study

Ren

Fajardo

et al. 2014

Journal of X-Ray Science and Technology

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BACKGROUND: Accurately depicting breast tumors located posteriorly, close to the chest wall musculature, with conventional mammography is a technical challenge. OBJECTIVE: This study demonstrates the proof of concept of an x-ray fluorescence mapping (XFM) technique to address this issue. METHODS: A tissue-equivalent gel phantom is designed to mimic structures in the central part of a compressed breast. The posterior aspect of the breast and adjacent pectoralis major muscle are represented by another 10-mm-thickness breast tissue simulation phantom (BR12) that is attached to the back of the gel phantom as a region of interest (ROI). Two gold nanoparticle (GNP) solutions are embedded into the ROI to simulate varying GNP uptake within breast lesions. The ROI is imaged through performing the XFM technique with an x-ray pencil-beam and a single spectrometer. RESULTS: A 2D mapping of the middle plane in the ROI demonstrates feasibility and matches well the known spatial distribution and different GNP concentrations. 3D reconstruction of the ROI is easily rendered by repeating the 2D mapping process. CONCLUSION: XFM system geometry and its insensitivity to attenuation coefficients of breast tissue components are unique characteristics that may complement conventional mammography and improve the detection of breast cancers located posteriorly, adjacent to or overlying the chest wall musculature.

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A method of measuring gold nanoparticle concentrations by x‐ray fluorescence for biomedical applications

Abstract: The investigation demonstrated the potential of imaging gold nanoparticles quantitatively in vivo for in-tissue studies, but future studies will be needed to investigate the ability to apply this method to clinical applications.

Cited by 23 publications

References 20 publications

Background estimation methods for quantitative x-ray fluorescence analysis of gold nanoparticles in biomedical applications

Background estimation methods for quantitative x-ray fluorescence analysis of gold nanoparticles in biomedical applications

Development of bimetallic (Zn@Au) nanoparticles as potential PET-imageable radiosensitizers

Detection of posteriorly located breast tumors using gold nanoparticles: A breast-mimicking phantom study

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