scholarly journals Assessing radiation dose limits for X-ray fluorescence microscopy analysis of plant specimens

2019 ◽  
Vol 125 (4) ◽  
pp. 599-610 ◽  
Author(s):  
Michael W M Jones ◽  
Peter M Kopittke ◽  
Lachlan Casey ◽  
Juliane Reinhardt ◽  
F Pax C Blamey ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Fluorescence Microscopy ◽  
Dose Rate ◽  
Structural Damage ◽  
X Ray ◽  
Distribution Of Elements ◽  
Dose Limits ◽  
Microscopy Analysis ◽  
Fluorescence Microscopy Analysis

Abstract Background and Aims X-ray fluorescence microscopy (XFM) is a powerful technique to elucidate the distribution of elements within plants. However, accumulated radiation exposure during analysis can lead to structural damage and experimental artefacts including elemental redistribution. To date, acceptable dose limits have not been systematically established for hydrated plant specimens. Methods Here we systematically explore acceptable dose rate limits for investigating fresh sunflower (Helianthus annuus) leaf and root samples and investigate the time–dose damage in leaves attached to live plants. Key Results We find that dose limits in fresh roots and leaves are comparatively low (4.1 kGy), based on localized disintegration of structures and element-specific redistribution. In contrast, frozen-hydrated samples did not incur any apparent damage even at doses as high as 587 kGy. Furthermore, we find that for living plants subjected to XFM measurement in vivo and grown for a further 9 d before being reimaged with XFM, the leaves display elemental redistribution at doses as low as 0.9 kGy and they continue to develop bleaching and necrosis in the days after exposure. Conclusions The suggested radiation dose limits for studies using XFM to examine plants are important for the increasing number of plant scientists undertaking multidimensional measurements such as tomography and repeated imaging using XFM.

Radiation Dose Limits for Bioanalytical X-ray Fluorescence Microscopy

2017 ◽  
Vol 89 (22) ◽  
pp. 12168-12175 ◽  
Author(s):  
Michael W. M. Jones ◽  
Dominic J. Hare ◽  
Simon A. James ◽  
Martin D. de Jonge ◽  
Gawain McColl
Keyword(s):  
Radiation Dose ◽  
Fluorescence Microscopy ◽  
X Ray ◽  
Dose Limits

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.

Encapsulated protamine-hyaluronic acid particles for targeting carboplatin directed by radiation

2017 ◽  
Vol 27 (01n02) ◽  
pp. 37-42
Author(s):  
T. Segawa ◽  
S. Harada ◽  
S. Ehara ◽  
K. Ishii ◽  
T. Sato ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Radiation Dose ◽  
Cancer Treatment ◽  
Standard Error ◽  
Room Temperature ◽  
Pixe Analysis ◽  
X Ray ◽  
Clinical Cancer

Encapsulated protamine-hyaluronic acid particles containing carboplatin were prepared and their ability to release carboplatin was tested in vivo. Protamine–hyaluronic acid particles containing carboplatin were prepared by mixing protamine (1.6 mg) and hyaluronic acid (1.28 mg) into a 5 mg/mL carboplatin solution for 30 min at room temperature. A 1 mL solution of protamine–hyaluronic acid particles was poured into an ampule of COATSOME[Formula: see text] EL-010 (Nichiyu, Tokyo, Japan), shaken three times by hand, and allowed to incubate at room temperature for 15 min. Following that, 10 or 20 Gy of 100 kiloelectronvolt (KeV) soft X-ray was applied. The release of carboplatin was imaged using a microparticle-induced X-ray emission (PIXE) camera. The amount of carboplatin released was expressed as the amount of platinum released and measured via quantitative micro-PIXE analysis. The diameter of the generated encapsulated particles measured [Formula: see text] nm (mean ± standard error). The release of carboplatin from the encapsulated protamine–hyaluronic acid particles was observed under a micro-PIXE camera. The amount of carboplatin released was [Formula: see text] under 10 Gy of radiation, and [Formula: see text] under 20 Gy of radiation, which was a sufficient dose for cancer treatment. However, 10 or 20 Gy of radiation is much greater than the dose used for clinical cancer treatment (2 Gy). Further research to reduce the radiation dose to 2 Gy in order to release sufficient carboplatin for cancer treatment is required.

scholarly journals Fluorescence Microscopy Analysis of Particulate Matter from Biomass Burning: Polyaromatic Hydrocarbons as Main Contributors

2015 ◽  
Vol 49 (11) ◽  
pp. 1160-1169 ◽  
Author(s):  
Patxi Garra ◽  
Christoph Maschowski ◽  
Céline Liaud ◽  
Alain Dieterlen ◽  
Gwenaëlle Trouvé ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Fluorescence Microscopy ◽  
Biomass Burning ◽  
Polyaromatic Hydrocarbons ◽  
Microscopy Analysis ◽  
Fluorescence Microscopy Analysis

Radiation Dose Measurement Technique of the X-Ray Source in the Process of Stabilization

2015 ◽  
Vol 1085 ◽  
pp. 478-481 ◽  
Author(s):  
Irina Miloichikova ◽  
Sergei Stuchebrov ◽  
Angelina Krasnykh ◽  
Alexander Wagner
Keyword(s):  
Radiation Dose ◽  
Dose Rate ◽  
Measurement Technique ◽  
Dose Measurement ◽  
Radiation Burden ◽  
X Ray ◽  
Thermoluminescent Dosimeters

In the article the radiation burden measurement technique of the X-ray source in the process of stabilization is described. The possibility of using this technique for the dose rate determination from the pulsed X-ray source is presented. The measurement technique approbation results at the pulsed X-ray source RAP-160-5 using thermoluminescent dosimeters DTL-02 are shown.

EVALUATION OF RADIATION DOSE IN DIFFERENT POSITIONS AROUND THE PATIENT TABLE DURING INTERVENTIONAL CARDIOLOGY PROJECTIONS

2019 ◽  
Vol 188 (2) ◽  
pp. 199-204
Author(s):  
Y Lahfi ◽  
A Ismail
Keyword(s):  
Radiation Dose ◽  
Radiation Exposure ◽  
Dose Rate ◽  
Radiation Protection ◽  
Interventional Cardiology ◽  
X Ray ◽  
Dose Rates ◽  
Patient Table ◽  
The Right

Abstract The aim of the present study was to evaluate the radiation exposure around the patient table as relative to the cardiologist position dose value. The dose rates at eight points presuming staff positions were measured for PA, LAO 30° and RAO 30° radiographic projections, and then normalized to the cardiologist’s position dose-rate value. The results show that in PA and RAO 30° projections, the normalized dose rate was higher by 9–22% at the right side of the table at a distance of 50 cm, while it was higher up to 31% at the left side for the same measured points in the LAO 30°. The differences of normalized dose rates for the both table sides were lower and decreased at farther positions. The obtained results correspond to the recommendations of staff radiation protection in Cath-labs with regards to X-ray tube and detector positions.

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