Monte Carlo simulation of a compact microbeam radiotherapy system based on carbon nanotube field emission technology

Schreiber, Eric; Chang, S

doi:10.1118/1.4728220

Cited by 18 publications

(15 citation statements)

References 56 publications

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“…There are several attempts to move toward alternative microbeam sources, such as laser accelerated protons 18 and inverse Compton scattering 19 . Also x‐ray tubes have been suggested as a microbeam source 20 . Hadsell et al 21 experimentally realized a preclinical setup with carbon nanotube x‐ray tubes and produced 300 μ m wide microbeams with a dose rate of 21.7 mGy/s per nanotube cathode.…”

Section: Introductionmentioning

confidence: 99%

A preclinical microbeam facility with a conventional x‐ray tube

et al. 2016

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Purpose:Microbeam radiation therapy is an innovative treatment approach in radiation therapy that uses arrays of a few tens of micrometer wide and a few hundreds of micrometer spaced planar x‐ray beams as treatment fields. In preclinical studies these fields efficiently eradicated tumors while normal tissue could effectively be spared. However, development and clinical application of microbeam radiation therapy is impeded by a lack of suitable small scale sources. Until now, only large synchrotrons provide appropriate beam properties for the production of microbeams.Methods:In this work, a conventional x‐ray tube with a small focal spot and a specially designed collimator are used to produce microbeams for preclinical research. The applicability of the developed source is demonstrated in a pilot in vitro experiment. The properties of the produced radiation field are characterized by radiochromic film dosimetry.Results:50 μm wide and 400 μm spaced microbeams were produced in a 20 × 20 mm2 sized microbeam field. The peak to valley dose ratio ranged from 15.5 to 30, which is comparable to values obtained at synchrotrons. A dose rate of up to 300 mGy/s was achieved in the microbeam peaks. Analysis of DNA double strand repair and cell cycle distribution after in vitro exposures of pancreatic cancer cells (Panc1) at the x‐ray tube and the European Synchrotron leads to similar results. In particular, a reduced G2 cell cycle arrest is observed in cells in the microbeam peak region.Conclusions:At its current stage, the source is restricted to in vitro applications. However, moderate modifications of the setup may soon allow in vivo research in mice and rats.

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Section: Introductionmentioning

confidence: 99%

A preclinical microbeam facility with a conventional x‐ray tube

et al. 2016

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“…Utilizing the unique capabilities of the CNT X-ray source array technology we recently demonstrated the feasibility of generating orthovoltage microbeam radiation (Zhou and Chang 2010, Schreiber and Chang 2012, Hadsell et al 2013). The prototype device utilized a specially designed CNT X-ray source array with a long and narrow focal track to deliver the radiation simultaneously from different directions, instead of from a single point, to the region of interest.…”

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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“…2012, Hsieh et al . 2013, Xu et al 2011, Shan et al 2013), image guided therapy (Maltz et al 2009) and small animal radiation therapy applications (Schreiber et al . 2012).…”

Section: Introductionmentioning

confidence: 99%

Studies of a prototype linear stationary x-ray source for tomosynthesis imaging

2014

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A prototype linear X-ray source to implement stationary source – stationary detector tomosynthesis imaging has been studied. Potential applications include human breast and small animal imaging. The source is comprised of ten X-ray source elements each consisting of a field emission cathode, electrostatic lens, and target. The electrostatic lens and target are common to all elements. The source elements form X-ray focal spots with minimum diameters of 0.3 to 0.4 mm at electron beam currents of up to 40 mA with a beam voltage of 40 kV. The X-ray flux versus time was quantified from each source. X-ray bremsstrahlung spectra from tungsten targets were produced using electron beam energies from 35 to 50 keV. The half-value layer was measured to be 0.8 mm, 0.9 mm, and 1.0 mm, respectively, for the 35 kV, 40 kV, and 45 kV tube potentials using the tungsten target. The suppression of voltage breakdown events, particularly during source operation, and the use of a modified form of the standard cold-cathode geometry, enhanced source reliability. The prototype linear source was used to collect tomographic data sets of a mouse phantom using digital tomosynthesis reconstruction methods and demonstrated a slice-sensitivity profile with a full-width-half-maximum of 1.3 mm. Lastly, preliminary studies of tomographic imaging of flow through the mouse phantom were performed.

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Monte Carlo simulation of a compact microbeam radiotherapy system based on carbon nanotube field emission technology

Abstract: Monte Carlo simulations demonstrate that the proposed compact MRT system design is capable of delivering a sufficient dose rate and peak-to-valley ratio for small animal MRT studies.

Cited by 18 publications

References 56 publications

A preclinical microbeam facility with a conventional x‐ray tube

A preclinical microbeam facility with a conventional x‐ray tube

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

Studies of a prototype linear stationary x-ray source for tomosynthesis imaging

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