Amount Of Dose Research Articles

Planar and tomographic imaging dosimetry comparing to develop a new radiopharmaceutical for melanoma therapy

This work aims to compare SPECT (Single Photon Emission Tomography Computed) and planar modalities as the most efficient methodology to perform dosimetry by molecular imaging. Twenty-one male C57BL6 mice induced with murine melanoma cell line B16-F10, administered 131I-Ixolaris were used for melanoma therapy. The procedures applied to them followed the standards described for the use of experimental animals, duly approved by the National Council for Animal Experimentation Control (CONCEA from Federal University of Rio de Janeiro. The accumulated activities were obtained in order to estimate the absorbed doses in each organ. Mass and metabolic differences between mice and humans were considered and used to extrapolate data acquired at different scales. From the dose factors provided by the MIRDOSE software, the absorbed doses in the target organs irradiated by the source organs were calculated and, finally, the effective dose was estimated. From the Student's t-hypothesis test performed in the accumulated activity, absorbed dose and S-factor quantities, there is no statistically significant difference between performing the image dosimetry from SPECT and planar acquired images.

Factors Associated with Failure of Botulinum Toxin Injection in Adductor Spasmodic Dysphonia.

Electromyography (EMG) Guided botulinum toxin (BTX) injection is considered first-line treatment for adductor spasmodic dysphonia (SD). Failure rate can range between 6% and 29%. Study objective was to determine which factors were associated with failure. This was a retrospective review conducted at a tertiary, academic center. Adductor SD patients presenting for BTX injections from August 2017 to October 2018 were eligible. Age, gender, Voice Handicap Index (VHI-10), Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), number of injections, disease duration, unilateral/bilateral injection, right/left injection, dose quantity, body mass index (BMI), professional voice user, employment, psychiatric comorbidity, breathiness, and dysphagia were investigated. Outcomes included failure as defined by the patient and dosage change. Univariate and multivariate statistical analysis was conducted. Sixty seven out of 564 injections (12%) were categorized as failure by 131 patients. In multivariate analysis, dosage change was associated with shorter duration of good effect (P < .001), BTX dose (P = .016), breathiness (P < .001), bilateral injection (P = .024), dysphagia (P = .012) and professional voice user (P = .021). Failure was associated with first injection with a new physician (P < .001), professional voice user P < .001) and lack of breathiness (P = .003). Failure rate was not associated with age, gender, VHI-10, CAPE-V, disease duration, left/right injection, dose quantity, BMI, psychiatric comorbidity, and dysphagia. Failure rate was 12% and associated with patients' first injection with a physician, professional voice user, and lack of breathiness. Dosage change occurred in 29% of injections and was associated with injection side effects, bilateral injections, BTX dose, professional voice user, and shorter duration of good effect.Level of evidence: 3.

Targeted alpha therapy: a critical review of translational dosimetry research with emphasis on actinium-225.

This review provides a general overview of the current achievements and challenges in translational dosimetry for targeted alpha therapy (TAT). The concept of targeted radionuclide therapy (TRNT) is described with an overview of its clinical applicability and the added value of TAT is discussed. For TAT, we focused on actinium-225 (225Ac) as an example for alpha particle emitting radionuclides and their features, such as limited range within tissue and high linear energy transfer, which make alpha particle emissions more effective in targeted killing of tumour cells compared to beta radiation. Starting with the state-of-the-art dosimetry for TRNT and TAT, we then describe the challenges that still need to be met in order to move to a personalized dosimetry approach for TAT. Specifically for 225Ac, we discuss the recoiled daughter effect which may provoke significant damage to healthy tissue or organs and should be considered. Next, a broad overview is given of the pre-clinical research on 225Ac-TAT with an extensive description of tools which are only available in a pre-clinical setting and their added value. In addition, we review the preclinical biodistribution and dosimetry studies that have been performed on TAT-agents and more specifically of 225Ac and its multiple progeny, and describe their potential role to better characterize the pharmacokinetic (PK) profile of TAT-agents and to optimize the use of theranostic approaches for dosimetry. Finally, we discuss the support pre-clinical studies may provide in understanding dose-effect relationships, linking radiation dose quantities to biological endpoints and even moving away from macro- to microdosimetry. As such, the translation of pre-clinical findings may provide valuable information and new approaches for improved clinical dosimetry, thus paving the way to personalized TAT.

Provision of Italian diagnostic reference levels for diagnostic and interventional radiology.

The diagnostic reference level (DRL) is a useful tool for the optimisation of medical exposures. Thus, a Working Party coordinated by the Italian National Institute of Health and the National Workers Compensation Authority has been formed to provide Italian DRLs, for both diagnostic and interventional procedures, to be used as appropriate for the implementation of the 2013/59 European Directive into the national regulation. The multidisciplinary Working Party was formed by professionals involved in diagnostic and interventional radiology medical exposures and started from a critical revision of both the literature and the results of previous Italian surveys. The procedures were divided into five sections for adult (projection radiography, mammography, diagnostic fluoroscopy, CT and interventional radiology) and two sections for paediatric patients (projection radiography and CT). The provided DRL values have been identified for "normal" adult patients and for age-classes of paediatric patients. Some of the DRL values provided by the Working Party are reported in this study as an example, divided by adult/paediatric patients, radiological technique and examination: specifically, DRLs for new radiological practices and new dose quantities as DRLs metric were introduced. The median value (rather than the mean) for each procedure, derived from a sample of patients, has to be compared with the corresponding DRL value, and dosimetric data related to a minimum number of patients should be collected for each examination. The approach to the definition and use of DRLs through guidelines of national Authorities in collaboration with scientific Associations should simplify the periodical updating and could be useful for keeping the optimisation of medical exposures faithful to the development of radiological practice.

Современная эпидемиологическая характеристика ветряной оспы в России

Introduction. The varicella vaccine introduction in the National immunization schedule is planned in Russia by 2020. Since 2013, vaccination against chicken-pox has been carried out according to epidemiological indications and as part of the regional immunization program in some regions. Material and methods. A descriptive epidemiological study has been carried out to assess the current epidemiological features of chicken-pox in Russia. A retrospective analysis of the incidence distribution in the time, age and territorial aspects was carried out, as well as taking into consideration the number of doses administered to certain population groups. Materials for research include the official data on incidence of chicken-pox and quantity of varicella vaccine doses administered in 2006-2018 in the country in general, and in two megalopolises – Moscow and St. Petersburg. Results. It is established that long-term and seasonal recurrence, the age structure and the epidemic nature of chicken-pox incidence did not change in comparison with the prevaccinal period due to low vaccination coverage of the children in country scales. On the example of the immunization program in Moscow, it is shown that vaccination before attendance at childcare allowed to reduce the incidence of children at the age of 3-6 years. However, a long-term epidemiological effect was not achieved due to incomplete vaccination coverage of the entire cohort of children. Conclusions. When introducing vaccination, it is necessary to strengthen the epidemiological surveillance of chicken-pox and its vaccine prophylaxis in order to timely respond to unfavorable trends of a shift in the age of chicken-pox occurrence.

Discrepancies in Written Versus Calculated Durations in Opioid Prescriptions: Pre-Post Study.

BackgroundThe United States is in the midst of an opioid epidemic. Long-term use of opioid medications is associated with an increased risk of dependence. The US Centers for Disease Control and Prevention makes specific recommendations regarding opioid prescribing, including that prescription quantities should not exceed the intended duration of treatment.ObjectiveThe purpose of this study was to determine if opioid prescription quantities written at our institution exceed intended duration of treatment and whether enhancements to our electronic health record system improved any discrepancies.MethodsWe examined the opioid prescriptions written at our institution for a 22-month period. We examined the duration of treatment documented in the prescription itself and calculated a duration based on the quantity of tablets and doses per day. We determined whether requiring documentation of the prescription duration affected these outcomes.ResultsWe reviewed 72,314 opioid prescriptions, of which 16.96% had a calculated duration that was greater than what was documented in the prescription. Making the duration a required field significantly reduced this discrepancy (17.95% vs 16.21%, P<.001) but did not eliminate it.ConclusionsHealth information technology vendors should develop tools that, by default, accurately represent prescription durations and/or modify doses and quantities dispensed based on provider-entered durations. This would potentially reduce unintended prolonged opioid use and reduce the potential for long-term dependence.

A kernel-based algorithm for the spectral fluence of clinical proton beams to calculate dose-averaged LET and other dosimetric quantities of interest.

To introduce a new analytical methodology to calculate quantities of interest in particle radiotherapy inside the treatment planning system. Models are proposed to calculate dose-averaged LET (LETd) in proton radiotherapy. A kernel-based approach for the spectral fluence of particles is developed by means of analytical functions depending on depth and lateral position. These functions are obtained by fitting them to data calculated with Monte Carlo (MC) simulations using Geant4 in liquid water for energies from 50 to 250MeV. Contributions of primary, secondary protons and alpha particles are modeled separately. Lateral profiles and spectra are modeled as Gaussian functions to be convolved with the fluence coming from the nozzle. LETd is obtained by integrating the stopping power curves from the PSTAR and ASTAR databases weighted by the spectrum at each position. The fast MC code MCsquare is employed to benchmark the results. Considering the nine energies simulated, fits for the functions modeling the fluence in-depth provide an average equal to 0.998, 0.995 and 0.986 for each one of the particles considered. Fits for the Gaussian lateral functions yield average of 0.997, 0.982 and 0.993, respectively. Similarly, the Gaussian functions fitted to the computed spectra lead to average of 0.995, 0.938 and 0.902. LETd calculation in water shows mean differences of -0.007±0.008keV/μm with respect to MCsquare if only protons are considered and 0.022±0.007keV/μm including alpha particles. In a prostate case, mean difference for all voxels with dose >5% of prescribed dose is 0.28±0.23keV/μm. This new spectral fluence-based methodology allows for simultaneous calculations of quantities of interest in proton radiotherapy such as dose, LETd or microdosimetric quantities. The method also enables the inclusion of more particles by following an analogous process.

A self learning algorithm based on data value lifecycle model for the accurate chemical dosing of wastewater treatment

In the process of wastewater treatment (WWT), the instability and hysteresis of the chemical dosing cannot make sure the stability of the water quality. At the same time, chemicals were wasted or overdosed in the process. In this study, we proposed a self learning algorithm, which based on the regression method modified using the data value lifecycle model to computer the accurate quantity of chemical dosing. The mechanisms of discard and cultivation data were established to make it alive in the algorithm. The algorithm is self learning according to the wastewater characteristics as the time goes on using the mechanism. We can make sure the quality of the wastewater is stability and economical by using the artificial intelligence. The experiment approves that the artificial intelligence algorithm was useful and economical to chemical dosing of wastewater treatment.

High yield of self-catalyzed GaAs nanowire growth on silicon (111) substrate templated by focused ion beam patterning

We report and detail a lithography-free method to pattern Si substrates. In particular, a focused Ga ion beam is used to create regular patterns of holes which serve as a template for the growth of vertically aligned GaAs nanowires (NW)s on Si(111) substrates using self-catalyzed molecular beam epitaxy. We show that the hole diameter plays a crucial role in the growth of the NWs at the drilled holes. The critical parameters defining the width of the holes are: ion dose quantities, wet etching procedures, and high-temperature steps at the process of growth. As a result, we obtained a yield of more than 80% for vertically aligned NW. Compared to other methods of patterning our approach provides the following advantages: (i) it is a lithography-free procedure, (ii) allows for quick patterning process and hole diameter optimization within a small window of trial and error, (iii) and provides potential applicability for different material systems.

EXTERNAL RADIATION SIMULATION OF LINAC TO DETERMINE EFFECTIVE DOSE IN ORGANS USING MONTE CARLO METHOD

The Linear particle accelerator (LINAC) is a tool for radiation therapy that can emit photons and electrons. Radiation of X-ray photons and LINAC electrons is obtained from the interaction of electrons fired into the target plate (tungsten). This radiation can not only affect the target organ but can also affect unwanted organs around the exposure area. Radiation irradiation effects on the organs in the exposure area can be known through simulation of LINAC and phantom radiation processes. Simulation and calculation using Monte Carlo method. This program is operated by MCNPX software. Phantom geometry uses the phantom ORNL MIRD, whereas linac geometry consists of linac blankets, tungsten plates and collimators. Radiation from linac is directed to the left lung as a target and from the simulation results of traces of radical particles shows that radiation emission from linac there are some scattering, but scattering this does not have a significant impact because the amount is not too large. Radiation effect on the organs is indicated by the effective dose quantities in which the left lung has a greater effective dose than the surrounding organs. While the right lung gets a large enough effect from other organs around the target organ. This is because the organ is located close to the target organ and has a smaller type of meeting of the other organs. Not so with the ribs, although it is the first organ exposed to radiation. Radiation that concerns the ribs has no significant effect. This is because of the enormous type of meeting. The effects of radiation on organs are not only influenced by the size of the meeting of organ types but also influenced by the weight factor.

1O2 determined from the measured PDT dose and 3O2 predicts long-term response to Photofrin-mediated PDT

Photodynamic therapy (PDT) that employs the photochemical interaction of light, photosensitizer and oxygen is an established modality for the treatment of cancer. However, dosimetry for PDT is becoming increasingly complex due to the heterogeneous photosensitizer uptake by the tumor, and complicated relationship between the tissue oxygenation ([3O2]), interstitial light distribution, photosensitizer photobleaching and PDT effect. As a result, experts argue that the failure to realize PDT’s true potential is, at least partly due to the complexity of the dosimetry problem. In this study, we examine the efficacy of singlet oxygen explicit dosimetry (SOED) based on the measurements of the interstitial light fluence rate distribution, changes of [3O2] and photosensitizer concentration during Photofrin-mediated PDT to predict long-term control rates of radiation-induced fibrosarcoma tumors. We further show how variation in tissue [3O2] between animals induces variation in the treatment response for the same PDT protocol. PDT was performed with 5 mg kg−1 Photofrin (a drug-light interval of 24 h), in-air fluence rates (ϕair) of 50 and 75 mW cm−2 and in-air fluences from 225 to 540 J cm−2. The tumor regrowth was tracked for 90 d after the treatment and Kaplan–Meier analyses for local control rate were performed based on a tumor volume ⩽100 mm3 for the two dosimetry quantities of PDT dose and SOED. Based on the results, SOED allowed for reduced subject variation and improved treatment evaluation as compared to the PDT dose.

Review of airkerma-area product, effective dose and dose conversion coefficients for non-cardiac interventional fluoroscopy procedures.

To provide current data on average air kerma-area product (PKA ) and effective dose (E) for noncardiac interventional fluoroscopy procedures and suggested values of dose coefficients (DCE ) for conversion of PKA to estimates of effective dose. A PubMed literature search covering the time period from 2006 to August 2019 was performed to obtain recent data on PKA , E and DCE for interventional fluoroscopy procedures. There is very wide variation in the reported values of PKA , E, and DCE in the literature. A number of factors are involved in this variability and the resultant uncertainty in average values of these dose quantities. The values of PKA , average E and suggested DCE presented here can be of use for comparison of the radiation detriment from different procedures and may be useful for categorizing detriment within an order of magnitude or so. They do not represent actual or expected radiation dose or detriment from any specific procedure or for a specific patient and should be not be used as such.

Amplification of Radiation-Induced Signal of LED Strip by Increasing Number of LED Chips and Using Amplifier Board

Transducers, such as photodiodes, phototransistors, and photovoltaic cells are promising radiation detectors. However, for accurate radiation detection and dosimetry, signals that emanate from these devices have to be sufficient to facilitate accurate calibrations, i.e., assigning a quantity of radiation dose to a specific magnitude of the signal. More so, purposely fabricated for luminescence, LEDs produce significantly low signals during radiation detection applications. Therefore, this paper investigates the enhancement and augmentation of photovoltaic signals that were generated when LED strips were being exposed to diagnostic X-rays. Initially, signal amplification was achieved through increasing the effective LED active area (from 60 to 120 chips); by successively connecting LED strips. Further, signal amplification was undertaken by injecting the raw LED strip signal into an amplifier board with adjustable gains. In both the signal amplification techniques, the tube voltage (kVp), tube current-time product (mAs), and source-to-detector distance (SDD) were varied. The principal findings show that effective active area-based signal amplifications produced an overall average of 91.16% signal enhancement throughout all of the X-ray parameter variations. On the other hand, the amplifier board produced an average of 36.48% signal enhancement for the signals that were injected into it. Chip number increment-based signal amplifications had a 0.687% less coefficient of variation than amplifier board signal amplifications. The amplifier board signal amplifications were impaired by factors, such as dark currents, amplifier board maximum operational output voltage, and saturation. Therefore, future electronic signal amplification could use amplifier boards having low dark currents and high operational voltage headroom. The low-cost and simplicity that are associated with active-area amplification could be further exploited in a hybrid amplification technique with electronic amplification and scintillators.

Investigation on the combustion and emission characteristics of CRDI diesel engine fuelled with nano Al2O3 and Fe3O4 particles blended biodiesel

This experimental investigation was carried out to suggest the suitable dose quantity of Al2O3 and Fe3O4 nanoparticles into mahua biodiesel blend (MME20) at which the best possible CRDI diesel engine combustion and emissions is reached. In this work, the dosing quantity of Al2O3 and Fe3O4 nanoparticles is varied from 40 to 120 ppm into the MME20 fuel blend with the assist of ultrasonicator. The Cetyl trimethyl ammonium bromide (CTAB) was utilized as cationic surfactant to increase the stability of dispersion of nanoparticles with MME20 fuel blend. The outcomes obtained from this experiment proved that the MME20 reduces the CRDI diesel engine brake thermal efficiency and increases its emission. The accumulation of Al2O3 and Fe3O4 nanoparticles was originate to enhance the brake thermal efficiency and combustion parameters. The best emission characteristics are obtained at a dosing of 80 ppm of Al2O3 and Fe3O4 nanoparticles. Similarly better combustion characteristics are observed at a dosing of 80 ppm of Al2O3 compared with Fe3O4 nanoparticles.

Competence of blended coagulants for surface water treatment

Owing to the advantages of the natural coagulants under study, the present objective is to study the efficiency of blended coagulants: alum and chitin; alum and sago; and alum + chitin + sago. In this attempt, we have reduced the quantity of alum dose and added increasing quantities of the natural coagulants. The surface water samples collected from nearby sources were analyzed for the following parameters pre- and post-treatment with the coagulants. Coagulation and flocculation experiments were carried out using conventional jar test apparatus. Turbidity removal was observed to be nearly 99.29% at all pH ranges and doses. Removal of conductivity, solids and hardness was 58.83%, 32.03% and 33.33%, respectively. From the results obtained, it can be observed that the efficiency of blended coagulants in removal of various physicochemical parameters from the waters was better when compared to individual coagulants. The floc size in blend coagulants was larger than that of single coagulants. The data obtained in this study indicated the coagulation efficiency could be enhanced by using the blend coagulant.

A novel composite silver nanoparticles loaded calcium oxide stemming from egg shell recycling: A potent photocatalytic and antibacterial activities

Industrial wastewater resulted from textile dyeing process is considered as a big environmental problem. Therefore, recycling of wastewater offers environmental and economic values specially if the materials used are resulted from recycling of other kinds of waste. From this point of view and for the first time this work deals with the study the wastewater recycling by calcium oxide resulted from eggshell recycling. Calcium oxide (CaO) nanocrystals were created by the thermal annealing of chicken egg shell at 1100 °C for 2 h s. Heat treatment at 200 °C in air for 2 h s of the resulted CaO with silver oxalate gave the novel composite, silver nanoparticles loaded calcium oxide (Ag-NPs @ CaO). By applying electronic spectra (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy with the energy dispersion spectrum analysis (SEM-EDX) and transmittance electronic microscope (TEM), the materials were characterized. The energy band gap was calculated from the equation of Tauc for CaO and Ag-NPs@CaO and measured to be 2.1 and 2 eV, respectively. Indigo carmine (IC) as a model of photocatalytic decolorization was performed using both CaO and Ag@CaO nanoparticles under sunlight exposure. The impacts of various variables such as solution pH, dose quantity, temperature and irradiation time were studied. Both catalysts displayed an effective photocatalytic activity in IC decolorization but Ag@CaO composite displayed a stronger activity than CaO. The percentages of dye degradation were ≈99.21% and 99.45% in case of CaO and Ag@CaO, respectively. The antibacterial efficiency was measured against some Gram-negative and Gram-positive bacteria. Ag@CaO provided powerful weapons against the drug-resistant bacteria. These findings give a promising and economic strategy for all those who are interested in industries which involve dyeing process.

Radiological impact assessment of soil and groundwater of Himalayan regions in Uttarakhand, India

In this study, we present the results of measurements and radiological impact of natural radioactivity in soil and groundwater of the Himalayan region in the Uttarakhand State of India. The concentrations of primordial radionuclides (226Ra, 232Th and 40K) in soil samples of the study area were determined using gamma-ray spectrometry by employing the NaI(Tl) detector. The concentrations of radon and uranium were also measured in potable groundwater samples using RAD7 and Inductively Coupled Plasma Mass Spectrometry (ICPMS) techniques, respectively. The average specific activities of 226Ra (116 Bq kg−1), 232Th (137 Bq kg−1) and 40K (735 Bq kg−1) in soil were found considerably higher than the corresponding global average values. The average concentrations of radon (35 Bq l−1) and uranium (1.3 µg l−1) in potable groundwater were found well within the safe limits recommended by the World Health Organization. The effects of natural radioactivity in soil and groundwater are discussed in terms of different risk assessment parameters and dose quantities.

182 Antimicrobial Stewardship in the Emergency Department: Leveraging the Electronic Health Record to Optimize Discharge Prescriptions

In 2014, the Centers for Disease Control and Prevention (CDC) estimated that 14.2 million antibiotic prescriptions were generated from emergency department (ED) visits. It is also estimated that at least 30% of outpatient antibiotic prescriptions are unnecessary and that the remaining 70% of prescriptions may benefit from improvements in antibiotic selection, dose, and duration of therapy. Use of clinical decision support (CDS) within the electronic health record (EHR), such as diagnosis-specific antibiotic prescription discharge order sets (with defaulted dose and dispense quantities), may assist ED providers in selecting guideline-concordant antibiotic regimens for common infectious disease states.

Experimentally-driven mathematical modeling to improve combination targeted and cytotoxic therapy for HER2+ breast cancer

The goal of this study is to experimentally and computationally investigate combination trastuzumab-paclitaxel therapies and identify potential synergistic effects due to sequencing of the therapies with in vitro imaging and mathematical modeling. Longitudinal alterations in cell confluence are reported for an in vitro model of BT474 HER2+ breast cancer cells following various dosages and timings of paclitaxel and trastuzumab combination regimens. Results of combination drug regimens are evaluated for drug interaction relationships based on order, timing, and quantity of dose of the drugs. Altering the order of treatments, with the same total therapeutic dose, provided significant changes in overall cell confluence (p < 0.001). Two mathematical models are introduced that are constrained by the in vitro data to simulate the tumor cell response to the individual therapies. A collective model merging the two individual drug response models was designed to investigate the potential mechanisms of synergy for paclitaxel-trastuzumab combinations. This collective model shows increased synergy for regimens where trastuzumab is administered prior to paclitaxel and suggests trastuzumab accelerates the cytotoxic effects of paclitaxel. The synergy derived from the model is found to be in agreement with the combination index, where both indicate a spectrum of additive and synergistic interactions between the two drugs dependent on their dose order. The combined in vitro results and development of a mathematical model of drug synergy has potential to evaluate and improve standard-of-care combination therapies in cancer.

The role of ICRP in medicine: past, present and future

The International X-ray and Radium Protection Committee was established in 1928 in response to concerns about effects of radiation exposure observed in radiologists. By 1950 the field of radiological protection had broadened beyond medical radiology and the committee was renamed the International Commission on Radiological Protection (ICRP). ICRP prepares fundamental recommendations on radiological protection that are adopted as the basis for standards, legislation, guidelines, programmes, and practices world-wide. The structure of ICRP consists of a main commission with four sub-committees, number three being established in 1977 to deal with protection in medicine. Task groups working under the direction of the committees prepare reports setting out recommendations and guidance on radiological protection in different areas. ICRP has created protection dose quantities that relate to risk, such as effective dose, that can be used for dose planning and comparison purposes. Committee 3 prepares short, concise reports aimed at specific needs of the medical community to promote accessibility. These give advice relating to many aspects of radiotherapy, diagnostic and interventional radiology, and nuclear medicine. In parallel with this work, modelling of dose distributions has been undertaken to derive coefficients for calculating patient doses from a wide range of radiopharmaceuticals. All ICRP reports over 2 years old will be available free of charge from January 2020 to aid the dissemination of information on radiological protection and help the medical community to adjust to challenges presented by new radiation techniques.