Efficiency of Gd2O2S: Eu Powder Phosphor as X-Ray to Light Converter under Radiographic Imaging Conditions

Michail, C.; Valais, I.; Toutountzis, A.; Seferis, I.; Georgousis, M.; Fountos, G.; Samartzis, Alexandros; Liaparinos, P.; Kandarakis, I.; Panayiotakis, G.

doi:10.1007/978-3-642-03879-2_222

Cited by 2 publications

(3 citation statements)

References 12 publications

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“…These laser properties can influence the energy of the ejected species arriving on the substrate [14]. A high plume density can be formed when the average intensity of the laser beam exceeds the ionization threshold of the material [15]. It should be noted that damages could be induced on the substrate at a very high plume density.…”

Section: The Evaporation Of the Ablated Materials Onto The Substratementioning

confidence: 99%

Latest Development on Pulsed Laser Deposited Thin Films for Advanced Luminescence Applications

2020

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Currently, pulsed laser deposition (PLD) is a widely used technique to grow thin films for academic research and for industrial applications. The PLD has superior advantages including versatility, control over the growth rate, stoichiometric transfer and unlimited degree of freedom in the ablation geometry compared to other deposition techniques. The primary objective of this review is to revisit the basic operation mechanisms of the PLD and discuss recent modifications of the technique aimed at enhancing the quality of thin films. We also discussed recent progress made in the deposition parameters varied during preparation of luminescent inorganic oxide thin films grown using the PLD technique, which include, among others, the substrate temperature. The advanced technological applications and different methods for film characterization are also discussed. In particular, we pay attention to luminescence properties, thickness of the films and how different deposition parameters affect these properties. The advantages and shortcomings of the technique are outlined.

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Section: The Evaporation Of the Ablated Materials Onto The Substratementioning

confidence: 99%

Latest Development on Pulsed Laser Deposited Thin Films for Advanced Luminescence Applications

2020

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“…Down conversion is a process in which absorption of a high energy X-ray photon yields the emission of numerous lower energy photons within the visible range [20][21][22][23][24]. The X-ray induced visible light emission spectral characteristics depend on the doping element in the lattice.…”

Section: Introductionmentioning

confidence: 99%

“…In this investigation, we utilized Terbium (Tb) as the doping agent which enabled a central peak emission at 544 nm. The phosphor Gd 2 O 2 S: Tb has been widely used in radiographic intensifying screens (scintillating screens) in medical imaging systems such as X-ray fluoroscopy, X-ray Computed Tomography, Single Photon Emission Tomography, and Positron Emission Tomography due to its high absorption of X-ray energy and its high conversion efficiency into visible light [21][22][23][24][25]. Gd 2 O 2 S:Tb has been reported to have high intrinsic conversion efficiency ∼ 15-20% into visible light energy [21,25].…”

Section: Introductionmentioning

confidence: 99%

Novel applications of diagnostic X-rays in activating a clinical photodynamic drug: Photofrin II through X-ray induced visible luminescence from "rare-earth" formulated particles

Abliz

Collins

Bell

et al. 2011

Journal of X-Ray Science and Technology

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Introduction: In this communication we report on a novel non-invasive methodology in utilizing "soft" energy diagnostic X-rays to indirectly activate a photo-agent utilized in photodynamic therapy (PDT): Photofrin II (Photo II) through X-ray induced luminescence from Gadolinium Oxysulfide (20 micron dimension) particles doped with Terbium: Gd2O2S:Tb. Photodynamic agents such as Photo II utilized in PDT possess a remarkable property to become preferentially retained within the tumor's micro-environment. Upon the photo-agent's activation through (visible light) photon absorption, the agents exert their cellular cytotoxicity through type I and type II pathways through extensive generation of reactive oxygen species (ROS); namely, singlet oxygen 1 O2, superoxide anion O − 2 , and hydrogen peroxide H2O2, within the intra-tumoral environment. Unfortunately, due to shallow visible light penetration depth (∼ 2 mm to 5 mm) in tissues, the current PDT strategy has largely been restricted to the treatment of surface tumors, such as the melanomas. Additional invasive strategies through optical fibers are currently utilized in getting the visible light into the intended deep seated targets within the body for PDT.Methods: X-ray induced visible luminescence from Gd2O2S:Tb particles were spectroscopically characterized, and the potential in-vitro cellular cytotoxicity of Gd2O2S:Tb particles on human glioblastoma cells (due to 48 Hrs Gd2O2S:Tb particle exposure) was screened through the MTS cellular metabolic assay. In-vitro human glioblastoma cellular exposures in presence of Photo II with Gd2O2S:Tb particles were performed in the dark in sterile 96 well tissue culture plates, and the corresponding changes in the metabolic activities of the glioblastoma due to 15 minutes of (diagnostic energy) X-ray exposure was determined 48 Hrs after treatment through the MTS assay.Results: Severe suppression (> 90% relative to controls) in the cellular metabolic activity of human glioblastoma was measured due to the treatment of clinically relevant concentrations of 20 µg/ml Photo II, with Gd2O2S:Tb particles, and (120 kVp) diagnostic X-rays. Taken together, the in-vitro findings herein provide the basis for future studies in determining the safety and efficacy of this non-invasive X-ray induced luminescence strategy in activating photo-agent in deep seated tumors.

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Efficiency of Gd2O2S: Eu Powder Phosphor as X-Ray to Light Converter under Radiographic Imaging Conditions

Cited by 2 publications

References 12 publications

Latest Development on Pulsed Laser Deposited Thin Films for Advanced Luminescence Applications

Latest Development on Pulsed Laser Deposited Thin Films for Advanced Luminescence Applications

Novel applications of diagnostic X-rays in activating a clinical photodynamic drug: Photofrin II through X-ray induced visible luminescence from "rare-earth" formulated particles

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