scholarly journals Determination of topographical radiation dose profiles using gel nanosensors

2019 ◽  
Vol 5 (11) ◽  
pp. eaaw8704 ◽  
Author(s):  
Karthik Pushpavanam ◽  
Sahil Inamdar ◽  
Subhadeep Dutta ◽  
Tomasz Bista ◽  
Thaddeus Sokolowski ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Radiation Doses ◽  
Anthropomorphic Phantom ◽  
Visual Change ◽  
Dose Mapping ◽  
Clinical Radiotherapy

Despite the emergence of sophisticated technologies in treatment planning and administration, routine determination of delivered radiation doses remains a challenge due to limitations associated with conventional dosimeters. Here, we describe a gel-based nanosensor for the colorimetric detection and quantification of topographical radiation dose profiles in radiotherapy. Exposure to ionizing radiation results in the conversion of gold ions in the gel to gold nanoparticles, which render a visual change in color in the gel due to their plasmonic properties. The intensity of color formed in the gel was used as a quantitative reporter of ionizing radiation. The gel nanosensor was used to detect complex topographical dose patterns including those administered to an anthropomorphic phantom and live canine patients undergoing clinical radiotherapy. The ease of fabrication, operation, rapid readout, colorimetric detection, and relatively low cost illustrate the translational potential of this technology for topographical dose mapping in radiotherapy applications in the clinic.

scholarly journals Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Time Flow ◽  
Highly Sensitive ◽  
Glass Column ◽  
On Line ◽  
Preconcentration Time ◽  
Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

scholarly journals Low-Dose Computed Tomography for the Optimization of Radiation Dose Exposure in Patients with Crohn’s Disease

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Richard G. Kavanagh ◽  
John O’Grady ◽  
Brian W. Carey ◽  
Patrick D. McLaughlin ◽  
Siobhan B. O’Neill ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Crohn’S Disease ◽  
Image Quality ◽  
Crohn's Disease ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Low Dose ◽  
Radiation Doses ◽  
Radiation Dose Exposure ◽  
Ct Technology

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (CT). There has been a significant increase in the utilization of computed tomography (CT) for patients with Crohn’s disease as patients are frequently diagnosed at a relatively young age and require repeated imaging. Between seven and eleven percent of patients with IBD are exposed to high cumulative effective radiation doses (CEDs) (>35–75 mSv), mostly patients with Crohn’s disease (Newnham E 2007, Levi Z 2009, Hou JK 2014, Estay C 2015). This is primarily due to the more widespread and repeated use of CT, which accounts for 77% of radiation dose exposure amongst patients with Crohn’s disease (Desmond et al., 2008). Reports of the projected cancer risks from the increasing CT use (Berrington et al., 2007) have led to increased patient awareness regarding the potential health risks from ionizing radiation (Coakley et al., 2011). Our responsibilities as physicians caring for these patients include education regarding radiation risk and, when an investigation that utilizes ionizing radiation is required, to keep radiation doses as low as reasonably achievable: the “ALARA” principle. Recent advances in CT technology have facilitated substantial radiation dose reductions in many clinical settings, and several studies have demonstrated significantly decreased radiation doses in Crohn’s disease patients while maintaining diagnostic image quality. However, there is a balance to be struck between reducing radiation exposure and maintaining satisfactory image quality; if radiation dose is reduced excessively, the resulting CT images can be of poor quality and may be nondiagnostic. In this paper, we summarize the available evidence related to imaging of Crohn’s disease, radiation exposure, and risk, and we report recent advances in low-dose CT technology that have particular relevance.

scholarly journals New approaches to biological dosimetry: development of complex biodosimetric systems (review of foreign literature)

2019 ◽  
pp. 90-96
Author(s):  
N. V. Sotnik ◽  
V. L. Rybkina ◽  
T. V. Azizova
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Biological Markers ◽  
Large Scale ◽  
Accurate Estimate ◽  
Dose Assessment ◽  
Radiation Doses ◽  
Biological Dosimetry ◽  
Radiation Accidents ◽  
Combined Use

Relevance. In case of emergency due to large-scale radiation accidents, biological dosimetry becomes a critical tool for early radiation dose assessment and enables identification of individuals exposed to ionizing radiation and facilitates further medical follow-up decisions.Intention. To assess the feasibility of a number of biological markers for bioindication and biodosimetry purposes based on literature data.Methodology. Literature sources were searched in MEDLINE databases, PubMed, CyberLeninka, elibrary.ru, using the terms: radiation, irradiation, biodosimetry. The review presents the results of studies from full-text sources of literature in English.Results and Discussion. Depending on an accidental exposure scenario, various biodosimetry techniques should be used to assess radiation doses with optimal accuracy and speed. In addition to physical methods and clinical techniques used to assess radiation doses, biological dosimetry defines a level of ionizing radiation exposure for certain individuals and is useful in making decisions about medical treatment strategy. To date, combined use of several biological markers within a biodosimetry system providing reliable radiation dose estimates.Conclusion. Analysis of the data presented in the review showed that combined use of several biological markers and development of a complex biodosimetric system will provide a more accurate estimate of doses, which is especially important in case of radiation accidents and incidents when physical dosimetry data are not available.

scholarly journals Ratiometric Colorimetric Detection of Nitrite Realized by Stringing Nanozyme Catalysis and Diazotization Together

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 280
Author(s):  
Mengzhu Wang ◽  
Peng Liu ◽  
Hengjia Zhu ◽  
Bangxiang Liu ◽  
Xiangheng Niu
Keyword(s):  
Detection Limit ◽  
Signal Analysis ◽  
High Efficiency ◽  
Colorimetric Assay ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Health It ◽  
Practical Applications ◽  
Higher Sensitivity

Due to the great threat posed by excessive nitrite in food and drinking water to human health, it calls for developing reliable, convenient, and low-cost methods for nitrite detection. Herein, we string nanozyme catalysis and diazotization together and develop a ratiometric colorimetric approach for sensing nitrite in food. First, hollow MnFeO (a mixture of Mn and Fe oxides with different oxidation states) derived from a Mn-Fe Prussian blue analogue is explored as an oxidase mimic with high efficiency in catalyzing the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation to blue TMBox, presenting a notable signal at 652 nm. Then, nitrite is able to trigger the diazotization of the product TMBox, not only decreasing the signal at 652 nm but also producing a new signal at 445 nm. Thus, the analyte-induced reverse changes of the two signals enable us to establish a ratiometric colorimetric assay for nitrite analysis. According to the above strategy, facile determination of nitrite in the range of 3.3–133.3 μM with good specificity was realized, providing a detection limit down to 0.2 μM. Compared with conventional single-signal analysis, our dual-signal ratiometric colorimetric mode was demonstrated to offer higher sensitivity, a lower detection limit, and better anti-interference ability against external detection environments. Practical applications of the approach in examining nitrite in food matrices were also verified.

Radiation (Gamma) Resistance and Postirradiation Growth of Listeria monocytogenes Suspended in Beef Bologna Containing Sodium Diacetate and Potassium Lactate†

2003 ◽  
Vol 66 (11) ◽  
pp. 2051-2056 ◽  
Author(s):  
CHRISTOPHER SOMMERS ◽  
XUETONG FAN ◽  
BRENDAN A. NIEMIRA ◽  
KIMBERLY SOKORAI
Keyword(s):  
Listeria Monocytogenes ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Foodborne Pathogen ◽  
Meat Products ◽  
Radiation Doses ◽  
Refrigerated Storage ◽  
Potassium Lactate ◽  
Sodium Diacetate

Listeria monocytogenes, a psychrotrophic foodborne pathogen, is a frequent postprocessing contaminant of ready-to-eat (RTE) meat products, including frankfurters and bologna. Ionizing radiation can eliminate L. monocytogenes from RTE meats. When they are incorporated into fine-emulsion sausages, sodium diacetate (SDA) and potassium lactate (PL) mixtures inhibit the growth of L. monocytogenes. The radiation resistance of L. monocytogenes, and its ability to proliferate during long-term refrigerated storage (9°C), when inoculated into beef bologna that contained 0% SDA–0% PL, 0.07% SDA–1% PL, and 0.15% SDA–2% PL, were determined. The radiation doses required to eliminate 90% of the viable L. monocytogenes cells were 0.56 kGy for bologna containing 0% SDA–0% PL, 0.53 kGy for bologna containing 0.07% SDA–1% PL, and 0.46 kGy for bologna containing 0.15% SDA–2% PL. L. monocytogenes was able to proliferate on bologna containing 0% SDA–0% PL during refrigerated storage, but the onset of proliferation was delayed by the addition of the SDA-PL mixtures. An ionizing radiation dose of 3.0 kGy prevented the proliferation of L. monocytogenes and background microflora in bologna containing 0.07% SDA–1% PL and in bologna containing 0.15% SDA–2% PL over 8 weeks of storage at 9°C. Little effect on lipid oxidation and color of the control bologna, or bologna containing SDA-PL mixtures, was observed upon irradiation at either 1.5 or 3.0 kGy.

scholarly journals Diagnostic Performance and Radiation Dose of the EOS System to Image Enchondromatosis: A Phantom Study

2020 ◽  
Vol 10 (24) ◽  
pp. 8941
Author(s):  
Domenico Albano ◽  
Alessandro Loria ◽  
Cristiana Fanciullo ◽  
Alberto Bruno ◽  
Carmelo Messina ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Low Dose ◽  
Background Radiation ◽  
Conventional Radiography ◽  
Radiation Doses ◽  
Repeatability Coefficient ◽  
Anthropomorphic Phantom ◽  
Interobserver Reproducibility ◽  
Radiology Resident ◽  
Plastic Foil

Background: Radiation doses and capability of EOS, conventional radiography (CR), and computed tomography (CT) to detect and measure enchondromas in a dedicated five-year-old anthropomorphic phantom were compared. Methods: To simulate enchondromas, minced pieces of chicken bone and cartilage were packed in conventional kitchen plastic foil to create ovoidal/rounded masses and randomly hung on the phantom. The phantom was imaged five times with CR, CT, and EOS, each time changing the number and position of inserts. All images were reviewed by a senior radiologist and a radiology resident. Results: EOS and CR detected all inserts in 4/5 cases (80%), while in one case 1/17 inserts was not seen. Excellent agreement of EOS with CR (88% reproducibility; bias = 14 mm; repeatability coefficient (CoR) 2.9; 95% CI from −2.8 to 3.1 mm; p = 0.5) and CT (81% reproducibility; bias = 15 mm; CoR 5.2; 95% CI from −5.5 to 5.2 mm; p = 0.7) was found. EOS showed 71% interobserver reproducibility (CoR 7.2; bias = 0.6 mm; 95% CI from −6.6 to 7.8 mm; p = 0.25). The EOS-Fast radiation dose was also significantly lower than the median radiation dose of CR (644.7 (599.4–651.97) mGy•cm2, p = 0.004). Conclusions: Low-dose EOS has the same capability as CR to detect and measure enchondroma-like inserts on a phantom and may be considered to monitor patients with multiple enchondromas.

scholarly journals Reducing ionizing radiation doses during cardiac interventions in pregnant women

2012 ◽  
Vol 5 (3) ◽  
pp. 108-111 ◽  
Author(s):  
Elizabeth Orchard ◽  
Sarah Dix ◽  
Neil Wilson ◽  
Lucy Mackillop ◽  
Oliver Ormerod
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Pregnant Women ◽  
Intracardiac Echocardiography ◽  
Radiation Doses ◽  
Child Bearing ◽  
Acquired Heart Disease ◽  
Low Exposure ◽  
Structural Disease ◽  
Ionizing Radiation Exposure

Background There is concern over ionizing radiation exposure in women who are pregnant or of child-bearing age. Due to the increasing prevalence of congenital and acquired heart disease, the number of women who require cardiac interventions during pregnancy has increased. We have developed protocols for cardiac interventions in pregnant women and women of child-bearing age, aimed at substantially reducing both fluoroscopy duration and radiation doses. Methods Over five years, we performed cardiac interventions on 15 pregnant women, nine postpartum women and four as part of prepregnancy assessment. Fluoroscopy times were minimized by simultaneous use of intracardiac echocardiography, and by using very low frame rates (2/second) during fluoroscopy. Results The procedures most commonly undertaken were closure of atrial septal defect (ASD) or patent foramen ovale (PFO) in 16 women, coronary angiograms in seven, right and left heart catheters in three and two stent placements. The mean screening time for all patients was 2.38 minutes (range 0.48–13.7), the median radiation dose was 66 (8.9–1501) Gy/cm2. The median radiation dose to uterus was 1.92 (0.59–5.47) μGy, and the patient estimated dose was 0.24 (0.095–0.80) mSv. Conclusions Ionizing radiation can be used safely in the management of severe cardiac structural disease in pregnancy, with very low ionizing radiation dose to the mother and extremely low exposure to the fetus. With experience, ionizing radiation doses at our institution have been reduced.

scholarly journals Dose mapping of products with different density irradiated in 60co irradiation facility of the Vinca institute, Serbia

2020 ◽  
Vol 35 (1) ◽  
pp. 56-63
Author(s):  
Bojan Rankovic ◽  
Nikolina Nikolic ◽  
Slobodan Masic ◽  
Ivica Vujcic
Keyword(s):  
Radiation Dose ◽  
Radiation Source ◽  
Complex Function ◽  
Absorbed Dose ◽  
Radiation Doses ◽  
Product Density ◽  
Dosimetry System ◽  
Absorbed Radiation Dose ◽  
Dose Mapping

The distribution of the absorbed dose within the irradiated product is a complex function of the product density and homogeneity, the position and shape of the radiation source, as well as the design of the irradiator. In this paper, detailed mapping of absorbed radiation doses in products of different density: gauze, plastic, and soil, is performed. Positions of minimum and maximum absorbed radiation dose were determined, and the homogeneity of irradiation of products was calculated using the ethanol-monochlorobenzene oscillotitrator dosimetry system.

scholarly journals A Low Cost and Simple Lab-on-a-Chip for Spectrophotometric Determination of Ethanol

2017 ◽  
Vol 15 (7) ◽  
pp. 529-539
Author(s):  
Thanyaluck SOMSAENG ◽  
Kem PUMSA-ARD ◽  
Piyada JITTANGPRASERT
Keyword(s):  
Limit Of Detection ◽  
Rapid Determination ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Lab On A Chip ◽  
Ceric Ammonium Nitrate ◽  
Alcoholic Beverages ◽  
Manufacturing Cost ◽  
Relative Standard

A simple lab-on-a-chip system was developed for the rapid determination of ethanol in different sample matrices, including gasohol and various alcoholic beverages. The colorimetric detection of ethanol using a spectrophotometer was based on the reaction between ethanol with 0.12 M ceric ammonium nitrate in acidic medium to produce a red colored product which gave a maximum absorption at 470 nm. A non-lithographic method was used for creating lab-on-a-chip molds to reduce  manufacturing cost and preparation steps. The lab-on-a-chip device was fabricated from polydimethylsiloxane which consisted of a simple Y-shaped working channel. Under optimum conditions, a linear calibration graph was obtained in the concentration range of 0.20 - 20 % (v/v) (r2> 0.999). The limit of detection (3 SD) and limit of quantification (10 SD) were 0.039 and 0.13 % (v/v), respectively. The precision reported in terms of relative standard deviation (RSD) values was less than 1.40 % (n = 15). To demonstrate the lab-on-a-chip’s performance, the determination of ethanol in gasohol and various alcoholic beverages was applied. The results obtained from the developed method compared with a standard gas chromatographic method were well correlated using the paired t-test and linear regression test. The results indicate that the proposed method has shown potential to extend the use of this simple lab-on-a-chip analytical device, due to its simplicity, low cost, lower reagent and sample consumption and high analytical performance. Moreover, the method of fabrication would be an additive manufacturing technique featuring a low equipment cost with no need for clean rooms.

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