Using National Electrical Manufacturers Association (NEMA) phantom, the behavior of four distinct Positron Emission Tomography/Computed Tomography (PET/CT) reconstruction algorithms was investigated. These reconstruction algorithms were (Ordered Subset Expectation Maximization (OSEM), OSEM+ (Point Spread Function) PSF, OSEM + Time of Flight (TOF), and OSEM + TOF + PSF), and the focus was on sphere sizes and SBRs using recovery coefficients as a quantitation method. The obtained results demonstrated the significant effect of TOF on Gibbs artifact and Partial Volume Effect (PVE) at various Sphere-to-Background Ratios (SBRs). TOF-based algorithms improved quantification accuracy and mitigated the influence of Gibbs artifact, particularly at higher SBRs. Compared to PSF algorithm, TOF- based algorithms effectively mitigated the impact of PVE on small-sized spheres and less dependent on SBRs. In terms of Standardized Uptake Value (SUV) quantification, SUVmean was better when utilizing TOF-based algorithms at lower SBRs, whereas SUVmax at higher SBRs. The combination of TOF and PSF produced a promising outcomes in quantifying and detecting a small-sized spheres across various SBRs, ultimately resulting in a more reliable and precise diagnostic information.

Aim: This study aimed to optimize the quantitative aspects of (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging by investigating the impact of various reconstruction parameters on the recovery coefficients (RCs) using the NEMA image quality phantom. Specifically, the study aims to assess how different matrix sizes, iterations, subsets, and Gaussian postfilters affect the accuracy of standardized uptake value (SUV) quantification in (18F) FDG PET/CT imaging. Materials and Methods: The study utilized the “Vue Point FX + Sharp IR” algorithm for PET image reconstruction, incorporating 3D-ordered subset expectation maximization (3D-OSEM), time-of-flight, and point spread function technologies. Various reconstruction parameters were explored, including two distinct matrix sizes, multiple iterations, subsets, and a wide range of Gaussian postfilters. The investigation focused on the impact of these parameters on RCs using the NEMA image quality phantom. Results: The results of the study indicated that for accurate SUV quantification in spheres ≥17 mm, the 256 × 256 matrix size and mean SUV should be employed. Conversely, for spheres ≤13 mm, maximum SUV was found to be more suitable. The choice of postfiltering value was shown to have a significant impact on SUV quantification accuracy, particularly for small-sized spheres. In addition, a larger matrix size was found to partially mitigate the effects of Gibbs artifact and slightly enhance SUV quantification for the spheres of various sizes. Conclusion: This study highlights the critical importance of optimizing PET reconstruction parameters in accordance with the guidelines set by European Association of Nuclear Medicine/EARL. By optimizing these parameters, the accuracy and reliability of SUV quantification in (18F) FDG PET imaging can be significantly enhanced, especially for small-sized spheres. This underscores the necessity of carefully considering reconstruction parameters to ensure precise and reliable quantitative measurements in PET/CT imaging.

One of the significant metrics that has lately emerged as a result of climate change is the Ultraviolet Index (UVI). In this work, the authors established a standardized reference UVI radiometer at NIS, Egypt, and discussed the performance to cover the actual actinic spectrum. Selective commercial UVI radiometers based on the proposed detector's responsivity and spectral mismatch were compared to the standardized reference UVI radiometer. The result indicated that the established detector response covers the entire UV actinic spectrum (280-405 nm). Besides, the standardized reference UVI radiometer has the least spectrum mismatch value with the (CIE) spectral response, according to a comparison between it and the other detectors that have been evaluated. Furthermore, it has the highest occupied area under the CIE spectral response curve, which is about 73.8%, and has about 12% better performance. These findings support to use of the established detector as a reference standard for detecting UVI at the radiometry lab at NIS Egypt.

According to ISO 9847, the indoor calibration of pyranometers is based on the use of light filament sources such metal halide and tungsten lamps that are similar to the sun spectrum. The application of LED light sources is currently promoted worldwide in every field. At NIS, a study on the LED pyranometer calibration system was carried out. The results revealed that, in the absence of a diffuser, the uniformity of the FEL lamp and LED source was 0.76 and 0.89, respectively; however, when a diffuser was used, the uniformity increased to 0.92 for the FEL lamp and 0.95 for the LED source. For both systems, the fixed holder’s presence decreased the divergency in repeatability; for the LED source, this was 2%, but for the FEL light, it was 11.5%. In terms of statistical analysis, although the LED calibration system is more stable than the FEL calibration system, none calibration method exhibits any sign of an out-of-control situation, indicating that changes caused by random error are controlled and satisfied. The comparison demonstrated that the filament sources in the pyranometer’s indoor calibration process might be replaced with an LED source.

Aim: This study aims to investigate the influence of voxel size and postfiltering on the quantification of standardized uptake value (SUV) in positron emission tomography/computed tomography (PET/CT) images. Materials and Methods: National Electrical Manufacturers Association phantom with the spheres of different sizes were utilized to simulate the lesions. The phantom was scanned using a PET/CT scanner, and the acquired images were reconstructed using two different matrix sizes, (192 × 192) and (256 × 256), and a wide range of postfiltering values. Results: The findings demonstrated that postfiltering significantly affected SUV measurements. The changes in postfiltering values can result in overestimation or underestimation of SUV values, highlighting the importance of carefully selecting appropriate filters. Increasing the matrix size improved SUVmax and SUVmean values, particularly for small-sized spheres. Smaller voxel reconstructions slightly reduced partial volume effects and partially enhanced SUV quantification. Conclusions: Careful consideration of postfiltering values and matrix size selection can lead to better SUV quantification. These findings emphasize the need to optimize the reconstruction parameters to enhance the clinical utility of PET/CT in detecting and evaluating malignant lesions.

The ultraviolet index UVI is a very important parameter used to inform the public about UV disadvantages . This can affect human health and lead to several issues. Many manufacturers have developed UV-index UVI radiometers based on the detection of the UV actinic spectral range. The response band of these radiometers is far from the actual actinic spectral range. This study aims to build a UVI detector of the actual actinic spectrum reaching the Earth to be used as a reference standard in the radiometry lab at NIS Egypt. The novelty of this study is the selection of a ready-manufactured sensor based on a GaP Schottky photodiode sensor to solve the defects in the present UVI radiometer and a careful selection of a short-pass filter and transmission diffuser. The calibration and measurement facilities available at NIS Egypt were used to describe the components. The designed detector response at 280–400 nm was used to capture the actual actinic spectrum. Several metrological studies were carried out in the laboratory to characterize the performance of the UVI detector, including spectral matching, angular response measurement, linearity, and spatial non-uniformity response. The results show and discuss the radiometric characterization of this detector.

The continuous need to calibrate radiometers makes us think and consider which of the utilized calibration methods provides the desired purpose with a high accuracy, high degree of stability in repeatability and reproducibility, and less estimated uncertainty value as possible. This study compares two common standard calibration methods that emerged and applied to two radiometers held in the radiometry lab at the National Institute of Standards (NIS), Giza, Egypt. The results concluded that the ND-filters method of calibration achieves the purpose of the study, exhibits more stability (STDEV 4% and 7%) and less combined uncertainty 2.7% and 9.4% for the two radiometers under test.

Light now has many applications in life and plays a vital role in therapeutic and protective fields. In the recent era, many light sources are considered for prevention, sterilization, and curing, especially with artificial lamps. Since the coronavirus pandemic appeared in 2019, the world has been interested in sterilization by light rays from a physical and applied point of view. In this work, the authors focus on definite spectral bands and their direct effects on the current COVID-19 pandemic for a prevention spreading purpose. According to the light use results, until now, the most useful method for decontamination against COVID-19 is ultraviolet C. The other spectral bands like UVA, UVB, and violet-blue show that they have a more negligible effect on the deactivation of the COVID-19 virus. The UVA and UVB help increase vitamin D in the human body, reflecting positively on the immunity system and increasing the recovery rate. The violet-blue band is helpful in decontamination against bacteria microorganisms. As for the IR band, the studies are still recent, and until now, there is no recommendation to use this band in sterilization against this pandemic. Studies continued on UV utilization because the world urgently needs industrial and domestic disinfection systems and sterilization. The other bands have another substantial practical effect on health improvement so any people can survive and overcome different diseases.

Museums and libraries hold many of archives which include photographic prints. These prints are affected by the ultraviolet rays in these places, whether it is from natural or industrial sources. This paper presents the assessment of the effect of UV rays on white and black gelatin photograph prints. Experimental samples were processed. Samples were exposed to ultraviolet rays. Photochemical and mechanical degradation was assessed before and after exposure. Mechanical change was assessed by testing tensile strength, elongation, and penetration strength. Colour change were assessed by using the CIE Lab system. Scanning Electron Microscope with signal unit elemental analysis (SEM-EDX) to assess morphology of surface. XRF analysis was used to identify change in the proportion of the elements that make up the image. ATR-IR spectroscopy to recognize the change in absorption frequency bands and the functional groups in the molecular of gelatin. UV radiation have a negative effect on the image of silver gelatin photograph prints.

Introduction: The most commonly used technique for detecting endometrial disease in women with AUB is 2D and 3D transvaginal ultrasound. The aim of the work: is to measure endometrial thickness, volume, RI and PI in women with peri-\postmenopausal bleeding and correlate it with histopathological results to discriminate between benign and malignant endometrial lesions. Patients and methods: This study is a controlled clinical trial that was conducted in El-Minia University Maternity Hospital, Egypt. Cases were collected from the outpatient clinic and inpatient gynecological department and 132 pre-&postmenopausal women were included in this study. All cases presented by AUB. The study was conducted between August 2017 and August 2019.The study was approved by the hospital ethical committee. The aim of this work is to measure endometrial thickness, volume ,RI and PI in women with peri-\postmenopausal bleeding and correlate it with histopathological results to discriminate between benign and malignant endometrial lesions. Results: In our study by comparing the AUCs of ET is 0.859 ,EV is 0.875 , PI is 0.902 and RI is 0.930, the best variable to predict malignancy is RI followed by PI followed by EV and lastly ET. Conclusion: 3D ultrasonography and Doppler, especially RI, may be useful for discrimination between benign and malignant endometrium in women with AUB.

The differences in repeatability measurements between one operator than another will affect the accuracy, precision and hence the uncertainty of the same device measurements. To try to avoid or reduce the variation in repeatability measurements between each operator, a special automated translation stage was designed to improve the accuracy of measurements at defined positions. This automated stage was applied to measure the irradiance levels of two phototherapy luminaires as an example of an exposing cabinet. The standard regulations recommend that the irradiance level of any exposed area must be collected at specified positions. The results of using an automated stage show that there are personal errors affecting the manual repeatability measurements. Using the automated stage in collecting data, the standard deviation of repeatability decreased significantly by 87.5% for LED luminaire and 43.3% for the fluorescent lamps luminaire. Besides, the automated stage saved the time and energy of the operator in the most accurate way.

THIS paper summaries the evaluation of using two different nano-particles as UV blocking standard materials for treatment of hi-performance fabrics after UVB exposure. Six woven samples are manufactured using three different weave structure (Twill 2/2, Satin 5, and Weft backed structure), two different high tenacity weft yarn count and materials (polyester and polypropylene) are used. Titanium dioxide - Zinc oxide nano-particles are used as a treated materials to reduce the effect of UVB radiations, after that the samples were exposed to UVB breaking strength and tear strength are performed according to standard test methods to estimate the fabrics performance. The data are statistically analyzed and evaluated for the six samples using t-test for mechanical properties. Scanning electron microscope and ultraviolet protection factor (UPF) are done for samples before and after treatment. The results of Ultraviolet protection factor test shows that nano-titanium oxide material has a better coating treatment than nano-zinc oxide.

This paper shows the experimental and analytical studies of gelatin behavior at photographic prints during the exposition to ultraviolet radiation.The test material used is black-and-white photographic paper.Different properties and characteristics of the prints have then been measured and compared before and after the irradiation.SEM used to study the surface topology of the gelatin.FTIR-ATR XRF analysis used to modify characteristic of the surfaces.Mechanical performance used to study.Color change was studied.The obtained results indicate a strong effect of the UV radiation in the color characteristics of the silver image, a certain change in the mechanical properties of the supporting paper and only slight consequences on the chemical properties of gelatin, which may probably increase with time.

The main purpose of this research work is to compare between two different calibration techniques for the spectrometer with CCD detectors. The emission spectra of two calibration lamp sources Hg(Ar) and Xe , and the transmission spectra of Holmium and Didymium standard glass filters are used to obtain wavelength calibration monochromator in the UV, visible, and near infrared spectral regions. Matching the output signal of the monochromator with the standard spectra of the sources and the transmission of the standard glass filters, we are able to determine and calculate the monochromator wavelength error of the obtained spectra. Subsequently, this error can be added to the uncertainty budget in wavelength calibrating of the monochromator. A detailed description of the set-up and how the calculation estimations are done are reported.

It is necessary to measure the irradiance levels to evaluate the effective dose delivered to the neonate from phototherapy devices. For such purpose, a broadband phototherapy radiometer has been used for measuring these phototherapy irradiance doses of plurality types of phototherapy sources. A phototherapy radiometer has been designed and during the construction its optical characteristics has been tested in collaboration between the National Institute of Standards in Egypt (NIS) and Department of Research And Development, Medical Engineering Group (MEG) Company. The most parameters required to characterize the performance of radiometer are the responsivity and uniformity. Then the present radiometer has been compared to other two available portable phototherapy radiometers in irradiance levels measurement. The calibration has been settled and the expanded uncertainties has been calculated according to the Guide to the expression of uncertainty in measurement (GUM) at coverage factor k = 2. The designed radiometer has responsivity range 415-495 nm with FWHM 35 nm which covers the phototherapy blue band. The radiometer results output summarized as; quantum efficiency is 84%, the uniformity 72% and measuring irradiance range 100-2500 µW.cm -2 .

The main aim of this research is to assess the variation in phototherapy radiometer responsivities toward the optical power of the phototherapeutic devices and hence estimate the spectral mismatch correction factor f1'. Two conventional phototherapy devices were studied to verify their spectral irradiance and three different phototherapy radiometers were studied for their responsivity at the range 400-500 nm. The results show the dependence of total irradiance measurement of phototherapy sources on matching between phototherapy radiometer band responsivity and spectral irradiance of the phototherapy sources. The spectral mismatch values vary from 13% to 47% of the total measured irradiance for the three radiometers. These mismatch values could be added to the measured irradiance as a correction.

Broadband Ultraviolet UV radiometers are widely used in a variety of applications including industrial process monitoring (e.g. UV curing, photolithography), medical testing, health and environmental testing, solar UV radiation measurement and other applications. Calibration of these instruments is necessary for accurate service. Calibration laboratories establish their own setup for calibration, which depends on the source of ultraviolet radiation. In this research three ultraviolet sources; (Deuterium lamp, Mercury arc lamp, Quartz Halogen Tungsten QTH lamp), are examined to find the most suitable one for the calibration system. The investigation of these sources based on measuring their spectral power distributions, uniformity and stability. It found that the QTH lamp has uniform distribution about 90.5% and high stability than deuterium and mercury arc lamps.In spectral range from 200 nm to 800 nm, Deuterium lamp emits 70% from its total radiation in the UV range, which is twice and half than that radiation emitted from mercury arc lamp.However, this work shows that the mercury arc lamp is the most suitable source for the calibration system of UVA radiometer.

THE TARGET of this work is to choose a suitable nanoparticle for preparing a highly ultraviolet (UV)-shielding from poly (methylmethacrylate) (PMMA) nanocomposites at low concentration and to decrease the destructive effects of UV radiation. Morphologies of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). Whereas, pure PMMA and its nanocomposites were characterized by using dynamic mechanical analysis (DMA), tensile testing, UV-visible spectra (T%), and thermogravimetric analysis (TGA). The obtained results showed a good correlation between the tensile properties, DMA and TGA analysis depending on the type of nanoparticles used in the PMMA matrix, especially in case of ZrO2 and ZnO. Furthermore, UV-vis spectra were analyzed ranging from 200 nm to 800 nm. It showed that UV radiation is significantly blocked from 100% to 0.2 % in the UV range between 200 nm and 360 nm for pure PMMA and to 0.08 % for PMMA/CeO2 nanocomposite and to 0.01 % for PMMA/CeO2 with various types of nanoparticles. After 360 nm, pure PMMA and PMMA/CeO2 were a little bit affected by UV lights, whereas the PMMA based on different nanoparticles was not affected. This result demonstrates that these nanocomposites could be strongly candidates for the sunscreens or for several fields that related to the UV photodegradation effects.

The most common therapeutic intervention used for the treatment of hyperbilirubinemia is phototherapy. The effectiveness of neonatal hyperbilirubinaemia treatment depends directly on the exposure to blue light (λ ≈ 450 nm) expressed by irradiance in W/m2. To assess the efficacy of the light source, a radiometric method was setup to ensure the competence of phototherapy devices (luminaire) to the standard international and national requirements. In this work, nine types based on fluorescent lamps which found to provide a uniformity higher than the minimum standards requirements (0.45 - 0.75), and four types based on Light Emitting Diodes (LEDs) phototherapy devices provide a uniformity (0.05 - 0.42). While as the irradiance levels obtained from lamps (˂ 8 – 26.7 µW/cm2/nm) and (33.3 – 122.2 µW/cm2/nm) from LEDs. Hence, NIS provides traceability to customer through unbroken chain of phototherapy radiometer calibrated as irradiance response in W/m2. Uncertainty model includes (calibration of the reference detector, distance effect, drift of the calibration, repeatability, and the resolution of the measuring device) are studied.

During recent years, white compact fluorescent lamps (WCFLs) have played a key role in energy efficient campaigns worldwide. As the use of WCFLs becomes increasingly widespread so also increases the concerns relating to their mercury content and the associated hazards. While the risk associated with individual WCFLs is generally concerned negligible, the cumulative impact of millions of WCFLs does however becomes a more significant issue and could represent a potential risk to the environment. The present study aimed to focus on the most useable lamps in the Egyptian markets; white compact fluorescent lamps (WCFLs) and to evaluate relationships between UV emissions radiated and illuminance compact fluorescent lamps (WCFLs). Various parameters such as ultra violet irradiance (UVA), ratio of UVA irradiance to electrical power (η) and ratio of UVA power to luminous flux (K), for two groups of CFLs are studied to dedicate their performance. A set up based on NIS-Spectroradiometer ocean optics HR 2000 has been used for measuring the spectral power distribution white WCFLs with different Egyptian market. Second set up for NIS-UVA silicon detector for absolute irradiance measurements and relative spectral power distribution based on Spectroradiometer are used. The absolute irradiance in W/m2 in UVA region of the lamps and their accompanied standard uncertainty are evaluated. Third set up based on NIS Luxmeter are used for measuring illuminance for these lamps. For all two groups under study, K parameter remains less than the safe limit for human health. Elios 32 watt WCFLs have smaller ratio (η) than Tiger 26 watt WCFLs. So, we recommended using Elios 32 watt WCFLs than Tiger 26 watt WCFLs at short distance in table lamps or other application and the distance more than 0.5 m. Uncertainty model includes all parameters accompanied with the measurements are calculated.