Gadolinium concentration analysis in brain phantom by X-ray fluorescence

Almalki, M.; Majid, Samir Abdul; Butler, P. H.; Reinisch, Lou

doi:10.1007/s13246-010-0020-x

Cited by 5 publications

(6 citation statements)

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“…The improvements in absolute detection efficiency, which offer the LE-Ge detector, compared to the CdTe detector typically reported for this purpose (Gräfe et al, 2011;Almalki et al, 2010), are hampered by a loss in the spectral resolution. To compensate this effect, detection geometry was analyzed and optimized to better reduce the contribution of the Compton in the fluorescent signal region of Gd and avoid overlaps of both signals.…”

Section: Setup Optimizationmentioning

confidence: 99%

“…Two different sources of 241 Am were simulated for the comparison with the optimized X-ray tube, for gadolinium quantification, using the gamma photons of 59.54 keV emitting with a 35.7% per decay rate. The activity of the first source was defined accordingly in order to consider generating an equal exposure to that produced by the optimized x-ray tube, so as to compare the advantages of the proposed method with similar reported in the literature (Almalki, 2010). One factor that affects the ability to properly assess improvements produced by the proposed method is the adding Cu filters in the configuration of the tube.…”

Section: Comparizon With 241 Am Sources and Calibration Curve For Quamentioning

confidence: 99%

“…These are in turn detected, indicating the presence of this element (Gräfe;2011;Gräfe et al, 2012). Similarly, Gd quantification by X-rays fluorescence (XRF) in phantom brain tumor have been implemented by 241 Am sources, using the 59 keV Gamma photons emitted with 35.7% probability per decay (Almalki et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…In the second stage, configurations that produce incident spectrums of same central energy (optimal energy determined) but with different FWHM were evaluated to determine the exposure produced to achieve the same limit of detection values (considering the different measurement time required in each configuration), and thus determine the settings which will produce the lowest dose and maximum sensitivity. In order to compare the proposed system with that available in the literature (Almalki et al, 2010), the limit of detection and measurement uncertainty obtained by the optimized system are compared with respect to the isotope source 241 Am (long life isotope with energy closer to the K absorption edge), with and without absorption filter, and an activity of the isotope source adjusted to produce the same exposure in the air than the tube. To implement the method in quantitative applications, a study of Gd quantification in tumors of different sizes and for concentrations in the therapeutic range recommended is performed (around 250 ppm) (Salt et al, 2004;De Stasio et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of EDXRF configurations to improve the limit of detection and exposure for in vivo quantification of gadolinium in tumor tissue

Santibáñez

Vásquez

Figueroa

et al. 2016

Radiation Physics and Chemistry

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Cite this article as: M. Santibáñez, M. Vásquez, R.G. Figueroa and M. Valente, Evaluation of EDXRF configurations to improve the limit of detection and exposure for in vivo quantification of gadolinium in tumor tissue, Radiation Physics and Chemistry, http://dx. Abstract.In this paper the configuration of an Energy Dispersive X-Ray Fluorescence (EDXRF) system optimized for in vivo quantification of gadolinium in tumor tissue was studied. The system was configured using XMI-MSIM software designed to predict the XRF spectral response using Monte Carlo simulations. The studied setup is comprised of an X-ray tube, tuned to different voltages, and a copper filter system configured with variable thickness, which emits a spectrally narrow beam centered on the specific excitation energy. The values for the central energy excitation and the spectral width were adjusted to optimize the system, using like figures of merit: minimization of the limit of detection, measurement uncertainty and radiation exposure. These values were obtained in two stages. The first was successive simulations of incident spectra with central energy in the range of 50-70 keV. The second was comprised of simulations with incident spectra of different widths (8-29 keV), all with the same determined central energy, evaluating the limit of detection depending on the exposure. This made it possible to find the best balance between system sensitivity and the delivered dose. The obtained results were compared with those produced by radioactive sources of 241 Am whose activity was set to produce the same exposure as the proposed setup. To evaluate the feasibility of in vivo quantification, a set of tumor phantoms of 1-6 cm 3 at different depths and labeled with a gadolinium concentration of 250 ppm was evaluated. From the resulting spectrum, calibration curves were obtained in function of the size and depth of the tumor, allowing for the evaluation of the potential of the methodology.

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Section: Setup Optimizationmentioning

confidence: 99%

Section: Comparizon With 241 Am Sources and Calibration Curve For Quamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of EDXRF configurations to improve the limit of detection and exposure for in vivo quantification of gadolinium in tumor tissue

Santibáñez

Vásquez

Figueroa

et al. 2016

Radiation Physics and Chemistry

View full text Add to dashboard Cite

show abstract

“…The locations and quantities of the GNPs can be effectively determined in vivo if both the spatial distribution and the amount of fluorescence within the region of interest can be quantified, which is typically accomplished by imaging the animal or human that has been injected. 8 Optical spectroscopy has successfully been utilized to determine the GNP quantification, 5,9 and microcomputed tomography can be utilized to image organs with GNP accumulations. 10 However, neither technique can successfully accomplish both requirements.…”

Section: Introductionmentioning

confidence: 99%