Carbon Nanotube‐Based Field Emission X‐Ray Technology

Zhang, Lei; Lü, Jianping; Lee, Yueh Z.; Chang, S; Zhou, Otto

doi:10.1002/9783527630615.ch26

Cited by 17 publications

(11 citation statements)

References 43 publications

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“…We recently developed a spatially distributed X-ray source array technology using the carbon nanotube (CNT) field emitters as a “cold cathode” (Zhou and Lu 2003, Zhang et al 2005, Zhou and Calderon-Colon 2010). The CNT cathode emits an electron beam under an applied electric field, which is then accelerated to bombard the metal anode to generate X-rays.…”

Section: Introductionmentioning

confidence: 99%

Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

Zhang¹,

Yuan²,

Burk³

et al. 2014

Phys. Med. Biol.

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Microbeam radiation therapy (MRT) is a promising experimental and preclinical radiotherapy method for cancer treatment. Synchrotron based MRT experiments have shown that spatially fractionated microbeam radiation has the unique capability of preferentially eradicating tumour cells while sparing normal tissue in brain tumour bearing animal models. We recently demonstrated the feasibility of generating orthovoltage microbeam radiation with an adjustable microbeam width using a carbon nanotube based X-ray source array. Here we report the preliminary results from our efforts in developing an image guidance procedure for the targeted delivery of the narrow microbeams to the small tumour region in the mouse brain. Magnetic resonance imaging was used for tumour identification, and on-board X-ray radiography was used for imaging of landmarks without contrast agents. The two images were aligned using 2D rigid body image registration to determine the relative position of the tumour with respect to a landmark. The targeting accuracy and consistency were evaluated by first irradiating a group of mice inoculated with U87 human glioma brain tumours using the present protocol and then determining the locations of the microbeam radiation tracks using γ-H2AX immunofluorescence staining. The histology results showed that among 14 mice irradiated, 11 received the prescribed number of microbeams on the targeted tumour, with an average localization accuracy of 454 μm measured directly from the histology (537 μm if measured from the registered histological images). Two mice received one of the three prescribed microbeams on the tumour site. One mouse was excluded from the analysis due to tissue staining errors.

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Section: Introductionmentioning

confidence: 99%

Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

Zhang¹,

Yuan²,

Burk³

et al. 2014

Phys. Med. Biol.

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“…[5,6] High aspect ratio carbon nanotubes (CNTs) revealed large field enhancement factor (generally larger than ≈10 3 ) and good field electron emission properties, [7][8][9] and have been used in field emission display (FED), [10,11] flat panel light source, [12] X-ray tube, [13,14] and microwave tube. [15,16] Semiconductor nanowires (e.g., ZnO, CuO) exhibited the field electron emission characteristics with low turn-on field and good uniformity, [17][18][19] and have been demonstrated to exhibit application prospect in flat panel X-ray source and detector.…”

Section: Doi: 101002/aelm201700295mentioning

confidence: 99%

An Analytical Modeling of Field Electron Emission for a Vertical Wedged Ordered Nanostructure

Shen

et al. 2017

Adv Elect Materials

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ties and potential applications: Spindt-type array composed of tapered microstructures have shown high current density over 1.6 × 10 3 A cm −2 with site density of 10 9 cm −2 , [2][3][4] and has been successfully applied in the traveling wave tube with the saturation power of 100 W and working frequency of 5 GHz. [5,6] High aspect ratio carbon nanotubes (CNTs) revealed large field enhancement factor (generally larger than ≈10 3 ) and good field electron emission properties, [7][8][9] and have been used in field emission display (FED), [10,11] flat panel light source, [12] X-ray tube, [13,14] and microwave tube. [15,16] Semiconductor nanowires (e.g., ZnO, CuO) exhibited the field electron emission characteristics with low turn-on field and good uniformity, [17][18][19] and have been demonstrated to exhibit application prospect in flat panel X-ray source and detector. [20,21] Although there is much experimental research and progress, theoretical analysis and calculation of field electron emission structure to tell people where the advantages lie and how to make improvements are still scarce, in order to obtain efficient field electron emission materials. Structural feature of materials affects some defining characteristics during the field electron emission process, including the field enhancement factor, local electronic field distribution, as well as actual emission sites and emission area. [22] And hence, it is of important significance to simulate and analyze the field emission structures and their corresponding emission properties. In this work, we focused on vertical tapered nanostructure and its derivative wedged ordered nanostructure. On the one hand, such nanostructures have the advantages that their sharp tips, large lengths, and vertical alignment help to bring large field enhancement factor and low turn-on field, [23,24] and their robust bottoms contribute to reducing the resistance and improving heat dissipation at high applied electric field. [25] On the other hand, these nanostructures could be obtained through existing preparation methods, whether top-down microprocessing or the bottom-up self-assembled growth. Table 1 lists the representative vertical tapered structural field emission materials and their derivatives. Majority of them have shown good field electron emission properties.Here, in order to develop a kind of field electron emission structure with high current density, vertical ordered tapered and wedged nanostructures have been analytically modeled and thoroughly studied. Local electrical field intensity and emission current density distributions have been simulated, and the The development of field electron emission materials requires purposeful analytical modeling of structural features. A vertical wedged ordered nanostructure shows better field emission current density because of its in-plane continuity at the top emission edge: Individually, its calculated average current density can be 8.3-26.7 times larger than a tapered nanostructure when its bottom area s increases from 0.5 to 2...

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“…We developed a spatially distributed field emission x-ray source array technology using carbon nanotubes (CNT) [24] [25–27]. In contrast to the current thermionic x-ray sources, it uses an electric field to extract electrons from one or multiple CNT cathodes at room temperature, which are focused and accelerated to bombard an anode to generate x-ray radiation.…”

Section: Nanotechnology Enables a Compact Microbeam Delivery Systemmentioning

confidence: 99%

Nanotube x-ray for cancer therapy: a compact microbeam radiation therapy system for brain tumor treatment

Zhang

Yuan

Inscoe

et al. 2014

Expert Review of Anticancer Therapy

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Microbeam radiation therapy (MRT) is a promising preclinical modality for cancer treatment, with remarkable preferential tumoricidal effects, that is, tumor eradication without damaging normal tissue functions. Significant lifespan extension has been demonstrated in brain tumor-bearing small animals treated with MRT. So far, MRT experiments can only be performed in a few synchrotron facilities around the world. Limited access to MRT facilities prevents this enormously promising radiotherapy technology from reaching the broader biomedical research community and hinders its potential clinical translation. We recently demonstrated, for the first time, the feasibility of generating microbeam radiation in a laboratory environment using a carbon nanotube x-ray source array and performed initial small animal studies with various brain tumor models. This new nanotechnology-enabled microbeam delivery method, although still in its infancy, has shown promise for achieving comparable therapeutic effects to synchrotron MRT and has offered a potential pathway for clinical translation.

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Carbon Nanotube‐Based Field Emission X‐Ray Technology

Cited by 17 publications

References 43 publications

Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

An Analytical Modeling of Field Electron Emission for a Vertical Wedged Ordered Nanostructure

Nanotube x-ray for cancer therapy: a compact microbeam radiation therapy system for brain tumor treatment

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