Purpose:
Optically stimulated luminescence (OSL) dosimetry has been recently introduced in radiation therapy as a potential alternative to the thermoluminescent dosimeter (TLD) system. The aim of ...this study was to investigate the feasibility of using OSL point dosimeters in the energy range used in diagnostic imaging.
Methods:
NanoDot OSL dosimeters (OSLDs) were used in this study, which started with testing the homogeneity of a new packet of nanoDots. Reproducibility and the effect of optical treatment (bleaching) were then examined, followed by an investigation of the effect of accumulated dose on the OSLD indicated doses. OSLD linearity, angular dependence, and energy dependence were also studied. Furthermore, comparison with LiF:Mg,Ti TLD chips using standard CT dose phantoms at 80 and 120 kVp settings was performed.
Results:
Batch homogeneity showed a coefficient of variation of <5%. Single-irradiation measurements with bleaching after each OSL readout was found to be associated with a 3.3% reproducibility (one standard deviation measured with a 8 mGy test dose), and no systematic change in OSLDs sensitivity could be noted from measurement to measurement. In contrast, the multiple-irradiation readout without bleaching in between measurements was found to be associated with an uncertainty (using a 6 mGy test dose) that systematically increased with accumulated dose, reaching 42% at 82 mGy. Good linearity was shown by nanoDots under general x-ray, CT, and mammography units with anR
2 > 0.99. The angular dependence test showed a drop of approximately 70% in the OSLD response at 90° in mammography (25 kVp). With the general radiography unit, the maximum drop was 40% at 80 kVp and 20% at 120 kVp, and it was only 10% with CT at both 80 and 120 kVp. The energy dependence study showed a range of ion chamber-to-OSLDs ratios between 0.81 and 1.56, at the energies investigated (29–62 keV). A paired t-test for comparing the OSLDs and TLDs showed no significant variation (p > 0.1).
Conclusions:
OSLDs exhibited good batch homogeneity (<5%) and reproducibility (3.3%), as well as a linear response. In addition, they showed no statistically significant difference with TLDs in CT measurements (p > 0.1). However, high uncertainty (42%) in the dose estimate was found as a result of relatively high accumulated dose. Furthermore, nanoDots showed high angular dependence (up to 70%) in low kVp techniques. Energy dependence of about 60% was found, and correction factors were suggested for the range of energies investigated. Therefore, if angular and energy dependences are taken into consideration and the uncertainty associated with accumulated dose is avoided, OSLDs (nanoDots) can be suitable for use as point dosimeters in diagnostic settings.
The use of laptop computer in our daily activities due to rapid changes in technology and industries has a great role in the fourth industrial revolution and directly or indirectly affect the way we ...learn, live and work. The research study intends to investigate the role of ergonomics and the impact of the use of laptop computer on biomechanics, visual and carrying discomfort among technology education professionals in Nigeria. The study used questionnaires, in order to collect data and empirical data were used for the descriptive analysis. The objectives are to examine how the use of laptop computer affect the biomechanics, visualization and carrying discomfort of the technology educators. The research so far discovered how laptop computer users faced problems like back pains, muscular pains, visual and carrying discomfort and lack of ergonomic knowledge and awareness among technical and vocational education professionals.
Over the past decade, immunotherapy delivered novel treatments for many cancer types. However, lung cancer still leads cancer mortality, and non-small-cell lung carcinoma patients with mutant EGFR ...cannot benefit from checkpoint inhibitors due to toxicity, relying only on palliative chemotherapy and the third-generation tyrosine kinase inhibitor (TKI) osimertinib. This new drug extends lifespan by 9-months vs. second-generation TKIs, but unfortunately, cancers relapse due to resistance mechanisms and the lack of antitumor immune responses. Here we explored the combination of osimertinib with anti-HER3 monoclonal antibodies and observed that the immune system contributed to eliminate tumor cells in mice and co-culture experiments using bone marrow-derived macrophages and human PBMCs. Osimertinib led to apoptosis of tumors but simultaneously, it triggered inositol-requiring-enzyme (IRE1α)-dependent HER3 upregulation, increased macrophage infiltration, and activated cGAS in cancer cells to produce cGAMP (detected by a lentivirally transduced STING activity biosensor), transactivating STING in macrophages. We sought to target osimertinib-induced HER3 upregulation with monoclonal antibodies, which engaged Fc receptor-dependent tumor elimination by macrophages, and STING agonists enhanced macrophage-mediated tumor elimination further. Thus, by engaging a tumor non-autonomous mechanism involving cGAS-STING and innate immunity, the combination of osimertinib and anti-HER3 antibodies could improve the limited therapeutic and stratification options for advanced stage lung cancer patients with mutant EGFR.
In this study, a needs analysis was conducted to identify the ergonomics awareness among technology education lecturers in Nigerian universities. In addition, the study was also designed to determine ...the gap in the existing technology curriculum with regard to ergonomic integration across the technology programs in Nigerian universities. Also, to determine the perception of lecturers toward the introduction of ergonomics-based technology education. Participants were 119 lecturers of technology education from selected Nigerian universities. Data were collected using questionnaires. Descriptive statistics such as means and standard deviation were used to describe the empirical data. The main result indicated a low level of ergonomics awareness among technology education lecturers in Nigerian universities. Also, with regards to the need of a new curriculum of ergonomics-based technology education, the study revealed that most respondents concur that a curriculum is needed. In fact, the majority of the lecturers perceived the incorporation of ergonomics-based technology education into technology education of the Nigerian universities as a milestone.
In the fields of the pharmaceutical and cosmetic industries and in toxicology, the study of the skin penetration of molecules is very interesting. Various studies have considered the impact of ...different physicochemical drug characteristics, skin thickness, and formulations, on the transition from the surface of the skin to the underlying tissues or to the systemic circulation; however, the influence of drug concentration on the permeation flux of molecules has rarely been raised. Our study aims to discover the influence of caffeine concentration in a formulation on the percutaneous penetration from gels, as a result of different dose applications to polysulfate membrane and human skin.
For this purpose, three identical base gels were used at 1, 3, and 5% of caffeine, to evaluate the effect of the concentration of caffeine on in vitro release through the synthetic membrane and ex vivo permeation through the human skin, using diffusion Franz(TM) cells.
The diffusion through the epidermal tissue was significantly slower than through the synthetic membrane, which recorded an increase of flux with an increase in the concentration of caffeine. The skin permeation study showed that diffusion depended not only on the concentration, but also on the deposited amount of gel. Nevertheless, for the same amount of caffeine applied, the flux was more significant from the less concentrated gel.
Among all the different concentrations of caffeine examined, 1% gel of caffeine applied at 5 mg / cm(2) showed the highest absorption characteristics across human skin.
The purpose of this study was to investigate the possibility of estimating pediatric thyroid doses from CT using surface neck doses. Optically stimulated luminescence dosimeters were used to measure ...the neck surface dose of 25 children ranging in ages between one and three years old. The neck circumference for each child was measured. The relationship between obtained surface doses and thyroid dose was studied using acrylic phantoms of various sizes and with holes of different depths. The ratios of hole-to-surface doses were used to convert patients' surface dose to thyroid dose. ImPACT software was utilized to calculate thyroid dose after applying the appropriate age correction factors. A paired t-test was performed to compare thyroid doses from our approach and ImPACT. The ratio of thyroid to surface dose was found to be 1.1. Thyroid doses ranged from 20 to 80 mGy. Comparison showed no statistical significance (p = 0.18). In addition, the average of surface dose variation along the z-axis in helical scans was studied and found to range between 5% (in 10 cm diameter phantom/24 mm collimation/pitch 1.0) and 8% (in 16 cm diameter phantom/12 mm collimation/pitch 0.7). We conclude that surface dose is an acceptable predictor for pediatric thyroid dose from CT. The uncertainty due to surface dose variability may be reduced if narrower collimation is used with a pitch factor close to 1.0. Also, the results did not show any effect of thyroid depth on the measured dose.
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