A new tomographic device based on the detection of fluorescent x-rays

Cesáreo, R.; Mascarenhas, S.

doi:10.1016/0168-9002(89)90802-4

Cited by 120 publications

(54 citation statements)

References 7 publications

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“…The detector model was based on a commercially available cadmium-telluride (CdTe) gamma and x-ray detector (XR-100T-CdTe, Amptek, Inc.), which had a beryllium window of 100 µm thickness, 1.27 mm behind which was a 3 × 3 × 1 mm 3 CdTe crystal serving as the active area of the detector. The detector housing, comprised of the head and base of the detector, was also modeled.…”

Section: A3 Cadmium-telluride X-ray Detector and Collimationmentioning

confidence: 99%

“…In recent years, a traditionally synchrotron based technique known as x-ray fluorescence computed tomography (XFCT) [1][2][3][4] has emerged as a valuable quantitative imaging tool which can be used to determine the biodistribution of high-Z metal probes such as iodine, gadolinium, platinum, and gold. While monochromatic x-rays are considered ideal 5 for XFCT, the impracticality of using synchrotrons in typical biomedical laboratory settings, especially for in vivo imaging of small animals, has motivated the implementation of XFCT on a benchtop setting using a polychromatic diagnostic energy-range x-ray source (viz., "benchtop XFCT").…”

Section: Introductionmentioning

confidence: 99%

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Improving x‐ray fluorescence signal for benchtop polychromatic cone‐beam x‐ray fluorescence computed tomography by incident x‐ray spectrum optimization: A Monte Carlo study

2014

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Purpose: To develop an accurate and comprehensive Monte Carlo (MC) model of an experimental benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) setup and apply this MC model to optimize incident x-ray spectrum for improving production/detection of x-ray fluorescence photons from gold nanoparticles (GNPs). Methods: A detailed MC model, based on an experimental XFCT system, was created using the Monte Carlo N-Particle (MCNP) transport code. The model was validated by comparing MC results including x-ray fluorescence (XRF) and scatter photon spectra with measured data obtained under identical conditions using 105 kVp cone-beam x-rays filtered by either 1 mm of lead (Pb) or 0.9 mm of tin (Sn). After validation, the model was used to investigate the effects of additional filtration of the incident beam with Pb and Sn. Supplementary incident x-ray spectra, representing heavier filtration (Pb: 2 and 3 mm; Sn: 1, 2, and 3 mm) were computationally generated and used with the model to obtain XRF/scatter spectra. Quasimonochromatic incident x-ray spectra (81, 85, 90, 95, and 100 keV with 10 keV full width at half maximum) were also investigated to determine the ideal energy for distinguishing gold XRF signal from the scatter background. Fluorescence signal-to-dose ratio (FSDR) and fluorescence-normalized scan time (FNST) were used as metrics to assess results. Results: Calculated XRF/scatter spectra for 1-mm Pb and 0.9-mm Sn filters matched (r ≥ 0.996) experimental measurements. Calculated spectra representing additional filtration for both filter materials showed that the spectral hardening improved the FSDR at the expense of requiring a much longer FNST. In general, using Sn instead of Pb, at a given filter thickness, allowed an increase of up to 20% in FSDR, more prominent gold XRF peaks, and up to an order of magnitude decrease in FNST. Simulations using quasimonochromatic spectra suggested that increasing source x-ray energy, in the investigated range of 81-100 keV, increased the FSDR up to a factor of 20, compared to 1 mm Pb, and further facilitated separation of gold XRF peaks from the scatter background. Conclusions: A detailed MC model of an experimental benchtop XFCT system has been developed and validated. In exemplary calculations to illustrate the usefulness of this model, it was shown that potential use of quasimonochromatic spectra or judicious choice of filter material/thickness to tailor the spectrum of a polychromatic x-ray source can significantly improve the performance of benchtop XFCT, while considering trade-offs between FSDR and FNST. As demonstrated, the current MC model is a reliable and powerful computational tool that can greatly expedite the further development of a benchtop XFCT system for routine preclinical molecular imaging with GNPs and other metal probes. C

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Section: A3 Cadmium-telluride X-ray Detector and Collimationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improving x‐ray fluorescence signal for benchtop polychromatic cone‐beam x‐ray fluorescence computed tomography by incident x‐ray spectrum optimization: A Monte Carlo study

2014

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“…Then, fluorescent x-ray scanning tomography was developed in order to investigate spatial distributions of specific elements. Fluorescent x-ray scanning tomography employing an x-ray tube has been used to study iodine in samples of several millimeters in diameter (Cesareo & Mascarenhas, 1989), while x-ray fluorescence scanning microtomography employing synchrotron radiation has been used in studies of Fe and Ti in 8-mm samples and in the detection of iron in a bee head (Boisseau & Grodzins, 1987). However, 2-dimensionally scanning a sample is time-consuming.…”

Section: Sr-fxct Based On Pencil Beam Geometrymentioning

confidence: 99%

Fluorescent X-Ray Computed Tomography Using Synchrotron Radiation Towards Molecular Imaging

Yuasa¹,

Takeda²

2012

Molecular Imaging

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“…The ®rst uorescent tomogram using X-ray tubes demonstrated a 0.5% iodine solution in a volume of 2.5 Â 2.6 Â 2.5 mm (Cesareo & Mascarenhas, 1989), and micro-tomography with synchrotron radiation showed iron in the head of a bee (Boisseau & Grodzins, 1987). In Japan,¯uorescent tomography with synchrotron radiation has been performed since 1993, and can detect about 200 ng of iodine in a 4 mm 3 volume (Takeda, Ito et al, 1994;Takeda, Maeda et al, 1995.…”

Section: Fluorescent X-ray Ctmentioning

confidence: 99%

Medical Applications with Synchrotron Radiation in Japan

Takeda

Itai

Hyodo

et al. 1998

J Synchrotron Radiat

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In Japan, various medical applications of synchrotron X-ray imaging, such as angiography, monochromatic X-ray computed tomography (CT), radiography and radiation therapy, are being developed. In particular, coronary arteriography (CAG) is quite an important clinical application of synchrotron radiation. Using a two-dimensional imaging method, the ®rst human intravenous CAG was carried out at KEK in May 1996; however, further improvements of image quality are required in clinical practice. On the other hand, two-dimensional aortographic CAG revealed canine coronary arteries as clearly as those on selective CAG, and coronary arteries less than 0.2 mm in diameter. Among applications of synchrotron radiation to X-ray CT, phase-contrast X-ray CT and¯uorescent X-ray CT are expected to be very interesting future applications of synchrotron radiation. For actual clinical applications of synchrotron radiation, a medical beamline and a laboratory are now being constructed at SPring-8 in Harima.

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A new tomographic device based on the detection of fluorescent x-rays

Cited by 120 publications

References 7 publications

Improving x‐ray fluorescence signal for benchtop polychromatic cone‐beam x‐ray fluorescence computed tomography by incident x‐ray spectrum optimization: A Monte Carlo study

Improving x‐ray fluorescence signal for benchtop polychromatic cone‐beam x‐ray fluorescence computed tomography by incident x‐ray spectrum optimization: A Monte Carlo study

Fluorescent X-Ray Computed Tomography Using Synchrotron Radiation Towards Molecular Imaging

Medical Applications with Synchrotron Radiation in Japan

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