scholarly journals Second generation of the diagnostic tool for the In vivo measurement of strontium levels in human bone

2021 ◽  
Author(s):  
Mira Sibai
Keyword(s):  
Diagnostic Tool ◽  
Bone Health ◽  
Second Generation ◽  
Current Source ◽  
X Rays ◽  
X Ray ◽  
Beneficial Effects ◽  
In Vivo Measurement ◽  
Signal Normalization

Strontium (Sr) is an element collected naturally in the human body through diet. It has a paradoxical effect on bone health, where at low doses Sr enhances bone health. The beneficial effects of Sr warranted its use as a complimentary treatment for osteoporosis. The current source-bases Sr in vivo x-ray fluorescence (IVXRF) system is in clinical use to study the incorporation and retention of Sr in bone after administration of Sr supplements. This system however can only monitor relative changes in bone with a limited level of accuracy. Therefore a second generation of the diagnostic tool has been developed and optimized aiming to improve the accuracy and precision of an IVXRF measurement. The system comprises of an optically focused x-ray tube producing monochromatic x-rays and a silicon drift detector. Furthermore, optimal parameters to run the system are investigated, along with three different means of signal normalization.

scholarly journals Second generation of the diagnostic tool for the In vivo measurement of strontium levels in human bone

2021 ◽  
Author(s):  
Mira Sibai
Keyword(s):  
Diagnostic Tool ◽  
Bone Health ◽  
Second Generation ◽  
Current Source ◽  
X Rays ◽  
X Ray ◽  
Beneficial Effects ◽  
In Vivo Measurement ◽  
Signal Normalization

Strontium (Sr) is an element collected naturally in the human body through diet. It has a paradoxical effect on bone health, where at low doses Sr enhances bone health. The beneficial effects of Sr warranted its use as a complimentary treatment for osteoporosis. The current source-bases Sr in vivo x-ray fluorescence (IVXRF) system is in clinical use to study the incorporation and retention of Sr in bone after administration of Sr supplements. This system however can only monitor relative changes in bone with a limited level of accuracy. Therefore a second generation of the diagnostic tool has been developed and optimized aiming to improve the accuracy and precision of an IVXRF measurement. The system comprises of an optically focused x-ray tube producing monochromatic x-rays and a silicon drift detector. Furthermore, optimal parameters to run the system are investigated, along with three different means of signal normalization.

Development of L-Line X-Ray Fluorescence Instrumentation and its Applications to In-Vivo Measurement of Lead in Bone

1994 ◽  
Vol 38 ◽  
pp. 573-577
Author(s):  
John E. Rosen
Keyword(s):  
Detection Limit ◽  
Count Rate ◽  
X Rays ◽  
Post Mortem ◽  
X Ray ◽  
In Vivo Measurement ◽  
Preliminary Study ◽  
Improved Design ◽  
Polarized Radiation

Initially, Wielopolski (Wielopolski et al. 1981) used x-rays from either a 125I or a 105Cd source to estimate lead (Pb) in tibial cortical bone in intact legs, post-mortem. This system utilized the Lα and Lβ x-rays of Pb with energies of 10.5 and 12.6 keV, respectively. The minimum detection limit (MDL) was considered to be comparable with existing K-line x-ray fluorescence (KXRF) instruments, namely, 20-30 ppm. The feasibility of partially polarized radiation (Barkla, 1906) was assessed from a 125I source on Pb (No3)2 (10,000 ppm) dissolved in wa:er. Reduction of the detector total count rate was observed by a factor of two; and reduction in background by the same factor was appaent. This preliminary study suggested that, with improved design, tlie MDL might be lowered by a factor of five (Wielopolski et al., 1981).

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

scholarly journals THE EFFECTS OF ROENTGEN RAYS ON CELL-VIRUS ASSOCIATIONS

1943 ◽  
Vol 78 (4) ◽  
pp. 285-304 ◽  
Author(s):  
William F. Friedewald ◽  
Rubert S. Anderson
Keyword(s):  
X Rays ◽  
Pathological Changes ◽  
Cellular Division ◽  
Papilloma Virus ◽  
X Ray ◽  
Crude Extracts ◽  
Domestic Rabbits ◽  
Roentgen Rays

The virus-induced papillomas of cottontail as well as domestic rabbits regress completely within a few weeks when exposed to 5,000 r of x-ray irradiation. The x-rays do not immediately kill the papilloma cells, but lead to death by inhibiting cellular division and producing pathological changes in the cells which then continue to differentiate. The virus associated with the growths, however, not only persists in undiminished amount during regression, but often an increased yield of it can be obtained on extraction. The fibroma virus in crude extracts or in vivo is inactivated by far less irradiation than the papilloma virus. 10,000 r destroys 90 per cent or more of the infectivity of the fibroma virus, whereas at least 100,000 r is required to inactivate 50 per cent of the papilloma virus in extracts containing about the same amount of protein. No variant of the papilloma virus or fibroma virus has been encountered as a result of the irradiation.

The in Vivo Measurement of Bone Lead Stores by 109Cd K X-Ray Fluorescence in a Non-Human Primate (Macaca mulatta)

1993 ◽  
pp. 315-318 ◽  
Author(s):  
Fiona E. McNeill ◽  
Andrew C. Todd ◽  
Bruce A. Fowler ◽  
N. K. Laughlin
Keyword(s):  
Macaca Mulatta ◽  
X Ray ◽  
In Vivo Measurement ◽  
Bone Lead ◽  
Human Primate

scholarly journals A hydroxyapatite phantom material for the calibration of in vivo x-ray fluorescence systems of bone strontium and lead quantification

2021 ◽  
Author(s):  
Eric Da Silva
Keyword(s):  
Monte Carlo ◽  
Soft Tissue ◽  
Monte Carlo Simulations ◽  
Calibration Procedure ◽  
X Rays ◽  
X Ray ◽  
Total Phosphate Concentration ◽  
High Concentrations ◽  
Phantom Material

A hydroxyaptite [HAp; Ca5(PO4)3OH] phantom material was developed with the goal of improving the calibration protocol of the 125I-induced in vivo X-ray fluorescence (IVXRF) system of bone strontium quantification with further application to other IVXRF bone metal quantification systems, particulary those associated with bone lead quantification. It was found that calcium can be prepared pure of inherent contamination from strontium (and other elements) through a hydroxide precipitation producing pure Ca(OH)2, thereby, allowing for the production of a blank phantom which has not been available previously. The pure Ca(OH)2 can then be used for the preparation of pure CaHPO4 ⋅ 2H2O. A solid state pure HAp phantom can then be prepared by reaction of Ca(OH)2 and CaHPO4 ⋅ 2H2O mixed as to produce a Ca/P mole ratio of 1.67, that in HAp and the mineral phase of bone, in the presence of a setting solution prepared as to raise the total phosphate concentration of the solution by increasing the solubility CaHPO4 ⋅ 2H2O and thereby precipitating HAp. The procedure can only be used to prepare phantoms in which doping with the analyte does not disturb the Ca/P ratio substantially. In cases in which phantoms are to be prepared with high concentrations of strontium, the cement mixture can be modified as to introduce strontium in the form of Sr(OH)2 ⋅ 8H2O as to maintain a (Ca + Sr)/P ratio of 1.67. It was found by both X-ray diffraction spectrometry and Raman spectroscopy studies that strontium substitutes for calcium as in bone when preparing phantoms by this route. The necessity for the blank bone phantoms was assessed through the first blank bone phantom measurement and Monte Carlo simulations. It was found that for the 125I-induced IVXRF system of bone strontium quantification, the source, 125I brachytherapy seeds may be contributing coherently and incoherently scattered zirconium X-rays to the measured spectra, thereby requiring the use of the blank bone phantom as a means of improving the overall quantification methodology. Monte Carlo simulations were employed to evaluate any improvement by the introduction of HAp phantoms into the coherent normalization-based calibration procedure. It was found that HAp phantoms remove the need for a coherent conversion factor (CCF) thereby potentially increasing accuracy of the quantification. Further, it was found that in order for soft tissue attenuation corrections to be possible using spectroscopic information alone, HAp along with a suitable soft tissue surrogate material need to be employed. The HAp phantom material was used for the evaluations of portable X-ray analyzer systems for their potential for IVXRF quantification of lead and strontium with a focus on a comparison between tungsten, silver and rhodium target systems. Silver and rhodium target X-ray tube systems were found to be comparable for this quantification.

scholarly journals X-ray Scatter Imaging of Hepatocellular Carcinoma in a Mouse Model Using Nanoparticle Contrast Agents

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Danielle Rand ◽  
Zoltan Derdak ◽  
Rolf Carlson ◽  
Jack R. Wands ◽  
Christoph Rose-Petruck
Keyword(s):  
Hepatocellular Carcinoma ◽  
Mouse Model ◽  
Contrast Agents ◽  
Malignant Tumors ◽  
Detection Methods ◽  
X Rays ◽  
X Ray ◽  
Enhanced Sensitivity ◽  
X Ray Imaging

Abstract Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide and is almost uniformly fatal. Current methods of detection include ultrasound examination and imaging by CT scan or MRI; however, these techniques are problematic in terms of sensitivity and specificity and the detection of early tumors (<1 cm diameter) has proven elusive. Better, more specific and more sensitive detection methods are therefore urgently needed. Here we discuss the application of a newly developed x-ray imaging technique called Spatial Frequency Heterodyne Imaging (SFHI) for the early detection of HCC. SFHI uses x-rays scattered by an object to form an image and is more sensitive than conventional absorption-based x-radiography. We show that tissues labeled in vivo with gold nanoparticle contrast agents can be detected using SFHI. We also demonstrate that directed targeting and SFHI of HCC tumors in a mouse model is possible through the use of HCC-specific antibodies. The enhanced sensitivity of SFHI relative to currently available techniques enables the x-ray imaging of tumors that are just a few millimeters in diameter and substantially reduces the amount of nanoparticle contrast agent required for intravenous injection relative to absorption-based x-ray imaging.

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