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Lung targeting was developed by synthesising pyrazolone derivatives 6a-f under solvent-free and thermal conditions by reacting azo coumarins 4a-c with hydrazines 5a and b using maltose as a biodegradable catalyst. Different spectral data characterized the synthesized agents as proton-NMR, FT-IR, and mass spectra. Direct radioiodination with iodine-131 was performed and optimized to reach the highest radiochemical purities (92 ± 0.47 to 98 ± 0.21%) using chloramine-T, a moderate oxidizing agent. The 131I-pyrazolone derivatives were confirmed based on HRMS. Furthermore, radioiodinated nitro-derivatives accumulated well in the lung of normal mice during in vivo evaluation, and the better uptake was for nitrophenyl-derivative 7f, about 30.06 ± 0.04% at 30 min after injection. Consequently, synthesized radioiodinated derivatives may be employed as prospective tracers for lung perfusion scans. • Synthesis and radiolabeling of a new pyrazole derivatives were done. • The effect of various reaction conditions on the percent radiochemical yield of radiolabeled derivative was studied. • The in vivo bioevaluation in normal mice showed good accumulation of radioiodinated pyrazole derivative in lung. • The synthetized pyrazole could be used as a potential lung imaging agents. [ABSTRACT FROM AUTHOR]

Abstract A radiotracer investigation was carried out in a wastewater stabilization pond using radiotracer technique. Residence time distribution (RTD) of wastewater was measured using Iodine-131 as a radiotracer. The measured RTD was treated and mean residence time (MRT) was determined. The measured MRT was compared with the theoretical MRT and dead volume was estimated. It was found that about 93% of the geometric volume within the anaerobic pond was dead. The measured RTD was modeled using various RTD models and eventually a suitable model was identified to describe and visualize the flow pattern of wastewater within the pond. Based on the measured MRT, estimated dead volume and identified flow patterns, it was concluded that the hydraulic performance of the anaerobic pond was very poor and not suitable for its intended purpose. Highlights • A radiotracer investigation was carried out in a wastewater anaerobic pond. • RTD of the wastewater was measured using Idoine-131 as a radiotracer. • Mean residence and dead volume were estimated. • Measured RTD was modeled using a complex flow model. • Flow patterns of wastewater were identified. [ABSTRACT FROM AUTHOR]

Abstract Radiotracer investigations were carried out in two identical phosphoric acid production reactors and a triple super phosphate (TSP) production reactor in three different plants in Tunisia. The main objective of the study was to investigate and compare their flow behavior and identify flow abnormalities, if any. Residence time distribution (RTD) of the process material (ore pulp) was measured in the three reactors using Iodine-131. The measured RTDs were treated and analyzed to obtain flow parameters such as the mean residence time (MRT), dead volume, and extent of bypassing. The treated RTD curves were modeled using a suitable mathematical model, and the values of the parameters were obtained. The results of the investigations were used to evaluate and compare the flow performance of the reactors, quantify the degree of mixing, and visualize the prevailing flow patterns. The results of the investigations are expected to be used to make necessary modifications to enhance the efficiency and optimize the performance of the reactors or the production process. Highlights • Radiotracer investigations were carried out in phosphate fertilizer production reactors. • RTD of process fluid was measured using Iodine-131 as radiotracer. • Mean residence time and dead volume were estimated. • A tank-in-series model with bypass was used to model the measured RTD. • Extent of bypassing was estimated, and flow patterns in the reactors were identified. [ABSTRACT FROM AUTHOR]

This paper discusses use of Monte Carlo simulations to facilitate testing and calibration of a gaseous effluent monitor (GEM). MCNP5 was used to simulate responses of the 131 I and 41 Ar GEM detecting units exposed to specific radioactive sources. The agreement between the MCNP5 predictions and experimental measurements is good enough to validate the MCNP5 model. It has been demonstrated that the Monte Carlo code is a powerful and useful tool to determine accurate detector responses and facilitate the calibration process of this type of the monitors. [ABSTRACT FROM AUTHOR]

A bilateral comparison between ENEA-INMRI (Italy) and NCBJ RC POLATOM (Poland) of 131 I-solution activity measurements was organized in the year 2015 and piloted by POLATOM, which provided the sources for the comparison. The 131 I master solution was standardized independently at both institutes by using Liquid Scintillation Counting and ionization chamber techniques. The 131 I master solution was then sent by POLATOM to the BIPM International Reference System (SIR). The comparison was registered as an EURAMET.RI(II)-K2.I-131 key comparison allowing the ENEA-INMRI result to enter in the SIR database. [ABSTRACT FROM AUTHOR]

A radiotracer investigation was carried out in an activated sludge process (ASP) system of an effluent treatment plant in a pulp and paper industry. The system consists of an aeration tank and a secondary clarifier connected in series. The primary objective of the investigation was to measure mean hydraulic retention times (MHRTs) of wastewater and investigate the hydraulic performance of the ASP. Residence time distributions (RTD) of the wastewater were measured in an aeration tank and a secondary clarifier of the system using Iodine-131 as a radiotracer. The measured RTD data was treated and MHRTs were estimated. No bypassing was found to exist in the aeration tank and the secondary clarifier. However, the dead volume in the aeration tank and the secondary clarifier was found and estimated to be 2.34% and 4.6%, respectively. The treated curves were further simulated using suitable hydraulically representative mathematical models and detailed flow patterns in the aeration tank and the secondary clarifier were deciphered. [ABSTRACT FROM AUTHOR]

Radioimmunotherapy is an established treatment modality in Non-Hodgkin's lymphoma. The only two commercially available radioimmunotherapies – 90 Y-ibritumomab tiuxetan is expensive and 131 I-tositumomab has been discontinued from commercial production. In resource limited environment, self-labelling 131 I-rituximab might be the only viable practical option. We reported our pioneer experience in Malaysia on self-labelling 131 I-rituximab, substituting autologous haematopoietic stem cell transplantation (HSCT) and a patient, the first reported case, received high dose 131 I-rituximab (6000 MBq/163 mCi) combined with BEAM conditioning for autologous HSCT. [ABSTRACT FROM AUTHOR]

During the production of iodine-131 from neutron irradiated tellurium dioxide by the dry distillation, a considerable amount of 131 I vapor is dispersed to the indoor air. People who routinely work at the production area may result in a significant risk of exposure to chronic intake by inhaled 131 I. This study aims to estimate the inhalation dose for individuals manipulating the 131 I at a radioisotope production. By using an application installed on smartphones, we collected the time-microenvironment data spent by a radiation group during work days in 2015. Simultaneously, we used a portable air sampler combined with radioiodine cartridges for grabbing the indoor air samples and then the daily averaged 131 I concentration was calculated. Finally, the time-microenvironment data jointed with the concentration to estimate the inhalation dose for the workers. The result showed that most of the workers had the annual internal dose in 1÷6 mSv. We concluded that using smartphone as a motion detector is a possible and reliable way instead of the questionnaires, diary or GPS-based method. It is, however, only suitable for monitoring on fixed indoor environments and limited the targeted people. [ABSTRACT FROM AUTHOR]

Intakes of radionuclides can be estimated through in vivo measurements, and the uncertainties associated to the measured activities should be clearly stated in monitoring program reports. This study aims to evaluate the uncertainties of in vivo monitoring of iodine 131 in the thyroid. The reference values for high-energy photons are based on the IDEAS Guide. Measurements were performed at the In Vivo Monitoring Laboratory of the Institute of Radiation Protection and Dosimetry (IRD) and at the Internal Dosimetry Laboratory of the Regional Center of Nuclear Sciences (CRCN-NE). In both institutions, the experiment was performed using a NaI(Tl) 3′′3″ scintillation detector and a neck-thyroid phantom. Scattering factors were calculated and compared in different counting geometries. The results show that the technique produces reproducibility equivalent to the values suggested in the IDEAS Guide and measurement uncertainties is comparable to international quality standards for this type of in vivo monitoring. [ABSTRACT FROM AUTHOR]

Discharge rates of water were measured in a canal using radiotracer methods with an objective to validate the efficacy of Concrete Volute Pumps (CVPs) installed at various pumping stations along the canal. Pulse velocity and dilution methods were applied to measure the discharge rates using Iodine-131 as a radiotracer. The discharge rate measured in one of the sections of the canal using the pulse velocity method was found to be 22.5 m 3 /s, whereas the discharge rates measured using the dilution method in four different sections of the canal varied from 20.27 to 20.62 m 3 /s with single CVP in operation. The standard error in discharge rate measurements using dilution method ranged from ±1.1 to ±1.8%. The experimentally measured values of the discharge rate were in good agreement with the design value of the discharge rate (20 m 3 /s) thus validating the performance of the CVPs used in the canal. [ABSTRACT FROM AUTHOR]

Using NIST-calibrated solutions of 131 Ba and 131 I in the 5 mL NIST ampoule geometry, measurements were made in three NIST-maintained Capintec activity calibrators and the NIST Vinten 671 ionization chamber to evaluate the suitability of using 133 Ba as a calibration surrogate for 131 I. For the Capintec calibrators, the 133 Ba response was a factor of about 300% higher than that of the same amount of 131 I. For the Vinten 671, the Ba-133 response was about 7% higher than that of 131 I. These results demonstrate that 133 Ba is a poor surrogate for 131 I. New calibration factors for these radionuclides in the ampoule geometry for the Vinten 671 and Capintec activity calibrators were also determined. [ABSTRACT FROM AUTHOR]

Brain cancer is a challenging disease to treat using conventional approaches. The present investigation aimed to develop a radiopharmaceutical targeting brain cancer based on natural isovanillin. Different parameters were optimized, resulting in high radiolabeling efficiency (97.3 ± 1.2%) and good stability (<48 h). The tracer was formulated for intranasal delivery in a chitosan nanoparticles system with a mean particle size of 141 ± 2 nm, a polydispersity index of 0.23 ± 0.02, and a zeta potential of −17.4 ± 0.3 mV to enhance nasal uptake and surmount the blood-brain barrier. The system was characterized and assessed in-vitro for suitability and specificity and evaluated in-vivo in normal and tumorized mice. The biodistribution profile in brain tumor showed 20.5 ± 0.4 %ID/g localization and cancer cell targeting within 60 min. Improvement in brain tumor uptake resulted from both the nanoformulation and nasal administration of iodoisovanillin. Overall, the reported results encourage the potential use of the nanoformulated labeled compound as an anticancer agent. • [131I]-isovanillin was obtained at high radiochemical yield (∼97.3%), and good stability (<48h). • [131I]-Isovanillin-chitosan nanoparticles system was prepared to enhance nasal uptake and surmount the blood-brain barrier. • The labeled nanoparticles showed a good specific cytotoxic effect versus the human U-25 cell line. • The biodistribution profile of labeled nanoparticles showed ∼20.5% localization and preferential brain tumor targeting. [ABSTRACT FROM AUTHOR]

Mixer-setters units are widely used in uranium purification processes. For efficient operations of mixer-settler units, it is essential to measure the hydrodynamics parameters of the different phases involved. The residence time distribution (RTD) measurement is commonly used method to estimate the hydrodynamics parameters of process reactors. In the present study, RTD of the aqueous phase was measured in different stages mixer-settler unit (mixers, settlers and mixer-settler units) used for stripping operation using Iodine-131 as a radiotracer. For the RTD measurements, radiotracer was injected as an impulse in aqueous phase feed line and its movement was monitored at different locations in the stripping unit using NaI(Tl) detectors. The mean residence times (MRTs) of the aqueous phase were estimated from measured RTD curves. For quantification of the degree of mixing, suitable flow models were proposed based on design and nature of the measured RTD curves and subsequently used for simulation. Based on the results of the RTD study, the mixing of aqueous phase was characterized and design of the stripping unit and its sub-units were validated. The optimum conditions were identified for efficient for the operation of the stripping unit. • The aqueous phase RTD in stripper unit and its sub-units was measured. • The MRT of the aqueous was estimated at different operating conditions. • Different flow models were used to quantify degree of mixing of aqueous phase. • The operating conditions of the stripping unit were optimized. [ABSTRACT FROM AUTHOR]

The diagnosis of intermittent claudication (IC) is challenging. Imaging with radiopharmaceuticals provides a new method for detecting acute IC. Pentoxifylline improves blood flow to ischemic tissues via increasing erythrocyte elasticity and inhibiting platelet aggregation. Pentoxifylline was radio-iodinated with radioiodine-131 (131I) through a direct electrophilic substitution reaction. Furthermore, various factors that might influence the radiolabeling strategy were investigated. The radiochemical yield of [131I]iodopentoxiphyline was evaluated by using paper chromatography and HPLC methods. The biodistribution pattern of [131I]iodopentoxiphyline was studied, where Swiss albino mice was used as a model of acute limb ischemia-reperfusion. The maximum radiochemical yield of pentoxifylline was found to be 94.11 ± 2.35%. The biodistribution findings revealed that [131I]iodopentoxiphyline was significantly deposited at the ischemic site (left hind limbs), with encouraging target/non-target (T/NT) ratios. At 0.25 and 1 h post injection, the uptake of [131I]iodo-pentoxifylline was 5.30 ± 0.30 and 9.98 ± 1.12%, respectively. Also, the maximum T/NT ratio for [131I]iodo-pentoxifylline (9.45 ± 0.26) was obtained at 0.25 h post injection. Due to safety and selectivity, [131I]iodo-pentoxifylline may be a good prospective diagnostic tool for early identification of IC. Moreover, the outcome of this study can be expected to apply to I-123 as well. • Pentoxifylline radiolabeled with iodine-131. • Various factors affecting radiochemical yield percentage were studied. • In vivo biodistribution pattern of [131I]iodopentoxiphyline was studied. • [131I]iodopentoxiphyline showed a marked accumulation at the ischemic site. [ABSTRACT FROM AUTHOR]

131 I is widely used in nuclear medicine for diagnostic and therapy of thyroid diseases. Depending of workplace safety conditions, routine handling of this radionuclide may result in a significant risk of exposure of the workers subject to chronic intake by inhalation of aerosols. A previous study including in vivo and in vitro measurements performed recently among nuclear medicine personnel in Brazil showed the occurrence of 131 I incorporation by workers involved in the handling of solutions used for radioiodine therapy. The present work describes the development, optimization and application of a methodology to collect and analyze aerosol samples aiming to assess internal doses based on the activity of 131 I present in a radiopharmacy laboratory. Portable samplers were positioned at one meter distant from the place where non-sealed liquid sources of 131 I are handled. Samples were collected over 1 h using high-efficiency filters containing activated carbon and analyzed by gamma spectrometry with a high-purity germanium detection system. Results have shown that, although a fume hood is available in the laboratory, 131 I in the form of vapor was detected in the workplace. The average activity concentration was found to be of 7.4 Bq/m 3 . This value is about three orders of magnitude below the Derived Air Concentration (DAC) of 8.4 kBq/m 3 . Assuming that the worker is exposed by inhalation of iodine vapor during 1 h, 131 I concentration detected corresponds to an intake of 3.6 Bq which results in a committed effective dose of 7.13×10 −5 mSv. These results show that the radiopharmacy laboratory evaluated is safe in terms of internal exposure of the workers. However it is recommended that the presence of 131 I should be periodically re-assessed since it may increase individual effective doses. It should also be pointed out that the results obtained so far reflect a survey carried out in a specific workplace. Thus, it is suggested to apply the methodology developed in this work to other nuclear medicine services where significant activities of 131 I are routinely handled as an effective means to optimize individual exposures and improve occupational radiation protection safety. [ABSTRACT FROM AUTHOR]

Abstract: Using anthropomorphic phantom in Geant4, determination of β- and γ-absorbed fractions and energy absorbed per event due to 131I activity in thyroid of individuals of various age groups and geometrical models, have been carried out. In the case of 131I β-particles, the values of the absorbed fraction increased from 0.88 to 0.97 with fetus age. The maximum difference in absorbed energy per decay for soft tissue and water is 7.2% for γ-rays and 0.4% for β-particles. The new mathematical MIRD embedded in Geant4 (MEG) and two-lobe ellipsoidal models developed in this work have 4.3% and 2.9% lower value of S-factor as compared with the ORNL data. [Copyright &y& Elsevier]

Abstract: Two methods for determination of internal dose due to 131I intake during the preparation and handling of iodine radiopharmaceutical products have been compared. The first method was based on the measurement of 131I in 24-hour urine samples while the second method was based on the measurement in vivo of 131I in thyroid. The results have shown that urine analysis method can be used as a screening test but not for internal dose assessment of exposed workers. Thyroid monitoring method was found to be more reliable and accurate method for assessing internal dose from 131I intake. In addition, the assessed internal dose showed that the annual internal effective dose for some workers was below 1mSv with no risk classification, whereas the results of other group of workers were between 1 and 6mSv with low risk classification. Only one worker reached 7.66mSv with high risk classification; and this worker must be monitored individually. [Copyright &y& Elsevier]

Khellin was successfully extracted from Ammi visnaga fruits with a recovery percent of 96.15%. Next radio-iodination of Khellin was successfully achieved with a high yield. The biodistribution study of [131I]iodo-khellin in tumour bearing mice revealed that khellin preferentially localization at tumour tissue. Target prediction study for [131I]iodo-khellin revealed that PI3K and VEGFR are potential targets for iodo-khellin with good affinity. The results of this study potentiate [131I]iodo-khellin as a good theranostic agent for tumour imaging and therapy. [Display omitted] • Khellin was extracted from the fresh fruits of Ammivisnaga and full characterized. • Radiolabeling of Khellin with 131I was successfully achieved with a high radiochemical yield. • In-vivo study of [131I]iodo-khellin in tumour bearing mice revealed its preferential localization at tumour tissue. • The docking study confirmed good affinity of iodo-khellin to the predicted targets. [ABSTRACT FROM AUTHOR]

Abstract: The studies undertaken by the 131I Working Group, part of the International Atomic Energy Agency''s EMRAS (Environmental Modelling for Radiation Safety) programme, were focused primarily on evaluating the predictive capability of environmental models. Particular emphasis was placed on applying models to evaluate the effectiveness of countermeasures. [Copyright &y& Elsevier]

Radioactive iodine-131 as both as free iodide (Na131I) and covalently bound to aniline (aniline-131I) was added to the drinking water of two Leghorn laying hens as a single dose and also as a cumulative dose over 1 week. The radioactivity of the principal parts of the eggs, i.e. shell, white, and yolk, was measured, and the radioactivity levels per gram material, and percent of the total radioactivity were calculated. The radioactivity measurements were continued for 1 month following the administration of 131I. In the case of the single dose administration, the results obtained showed that about 15% of the total radioactivity administered as Na131I was transported into the egg structure; compared to only about 1% for aniline-131I. After cumulative administration, about 15% of the total administered radioactivity was transported into the egg structure with both forms of 131I. This was probably because of metabolic cleavage of iodine bonds in the labeled aniline molecules during the longer period of exposure. These results also showed considerable accumulation of 131I in the egg yolks. In the case of the single dose administration, 131I can be detected in eggs up to about 20 days after administration, and up to about 30 days, in the case of the cumulative administration over 1 week. [Copyright &y& Elsevier]

In recent years, radioactive particle tracking (RPT) has emerged as a powerful noninvasive technique for characterization and visualization of flow in opaque multiphase flow reactors. This technique has been applied to a variety of multiphase flow reactors largely based on the theoretical framework for optimal design and performance parameters. No systematic evaluation and validation of the design and performance parameters of the RPT technique has been reported in the literature thus far. Consequently, the theoretical framework for the design of RPT experiments has had limited scalability and application to a wide variety of flow systems. Thus far, design of a "good" RPT experiment continues to be an art, no matter how much the richness of flow of information that the experimental method brings. The present work reports systematic experimental evaluation of design parameters for an optimal RPT experiment and validation of the theoretical results reported in literature. The experiments were performed in a carefully designed setup in which precise positioning of the tracer particle was made possible. The experiments assess the effect of various parameters on the performance of the RPT experiment, such as the choice of radioactive isotope, activity, gamma-ray energy, size of the detector, and relative positioning of detectors. Finally, a set of recommendations based on experimental work are provided to "optimally" perform the RPT experiment in any single or multiphase reactor. • The design parameters of RPT were experimentally evaluated. • The theoretical results reported in the literature of theoretical evaluation were validated. • Scandium-46 was found to be the most suitable radioisotope for RPT studies. • NaI (Tl) detector with a crystal size of 5 cm × 5 cm was found to be most efficient. • Three detectors in a particular plane were sufficient to obtain accurate results. [ABSTRACT FROM AUTHOR]