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In this study, three starch hydrogels composite prepared using different ratios of starch, citric acid, acrylamide, and MgO nanoparticles (referred to as St1-g-(CA-AM), St2-g-(CA-AM), and St3-g-(CA-AM) MgO). These materials were assessed using FT-IR, SEM, and EDX. The adsorption of 134Cs(I) and 60Co (II) onto these materials studied using radiometric analysis. The investigation focused on how temperature, contact duration, initial metal ion concentration, and pH of the solution affected the sorption efficiency. It is found that a pH value of 7 optimized the adsorption reaction, reaching equilibrium after 40 minutes. The kinetics of the adsorption followed a pseudo-second order model. The Langmuir model adequately explained the sorption mechanism, supported by the analysis of isotherm models. The monolayer adsorption capacities for 60Co (II) and 134Cs (I) were 113.38 and 100.2 mg g−1, respectively. The thermodynamic study indicated that the sorption process is both endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

Background: Adjuvant radiotherapy after mastectomy or breast conserving surgery (BCS) is the standard of care for majority of patients with breast cancer. This is however associated with mucosal and epidermal toxicity of organs at risk (OARs). Breast cancer patients are exposed to a plethora of wrong perceptions, misinformation and myths concerning the usefulness and adverse effects of radiotherapy. There is paucity of literature on the incidence and severity of radiation-induced acute toxicities experienced by patients with breast cancer in Ghana. Aim: To assess the occurrence and severity of four main acute radiation-induced toxicities among female breast cancer patients treated with external beam radiotherapy at a major cancer treatment centre in Ghana. Methods: Data on the occurrence of acute toxicities among patients was collected from patients' medical records, through a semi-structured questionnaire and via weekly clinical assessments. The Common Terminology Criteria for Adverse Events (CTCAE) grading scale (version 4.0) was used to grade the severity of these toxicities. Descriptive and inferential statistics using an independent two-sampled t-test (two-tailed), one-way analysis of variance (ANOVA), Pearson's Chi-square and Fisher's exact tests were performed. Results: Dermatitis, fatigue, pharyngitis, and breast (chest) pain were the radiation toxicities found among the breast cancer patients undergoing treatment on the two machines. The mean predominant radiation doses associated with the onset of dermatitis, fatigue, pharyngitis, and chest pain in the breast cancer patients were 22.32 Gy, 22.48 Gy, 13.59 Gy, and 19.27 Gy respectively for treatment with a statistically significant (p = 0.0173). Radiation dermatitis was the most dominant acute radiation toxicity recorded, and its incidence and severity. The range of Fisher's p-values (0.689–0.999) between the acute radiation toxicities with both machines revealed no statistical significance. Conclusion: Radiation dermatitis was the dominant acute toxicity, both in incidence and severity for patients treated. There was no statistical significance in the incidence and severity of acute radiation side effects.

Plastics have become the preferred materials for use due to their barrier properties and strength. This study aimed to determine the wettability, contact angle, and polymer chemical properties by comparing pure and mixed starch bioplastics with different plasticizers. Gamma radiation and electron beams are used in industrial applications. Gamma radiation is used because it is extreme in penetration, and Cobalt-60 is often used for sterilization. Most bioplastics with citric acid as the plasticizer produced a high contact angle and achieved hydrophobicity. Materials used in constant amounts are distilled water and glycerol. Others manipulate variables based on the presence of starch, such as corn, potato, rice, or a mixture of the two starches. The Samples were characterized using tensile and elongation tests, water contact angle, Fourier Transform Infrared (FTIR) analysis, topography using Atomic Force Microscopy (AFM), moisture content tests, and biodegradability tests. Potato and corn-rice bioplastics have low moisture contents. Meanwhile, the corn bioplastic degraded faster at 80.17%. Potato rice with citric acid lead tensile test with 4.095 MPa. However, potatoes with sorbitol lead with 34.57% for the elongation case. FTIR analysis identified the functional groups of the normal polymeric OH and C-H stretching of the methylene group at wavenumbers of 3280–3300 cm-1 and 2920–2935 cm-1, respectively. According to FTIR analysis, corn rice with the presence of citric acid bioplastic was chosen to undergo AFM to survey roughness in case to determine whether crosslinking might happen; the different average roughness between pre-irradiated and post-irradiated samples is 8.82 nm. Based on these findings, bioplastics may contribute tremendous benefits, especially in smart packaging applications. [ABSTRACT FROM AUTHOR]

Purpose: A novel compensator‐based system has been proposed which delivers intensity‐modulated radiation therapy (IMRT) with cobalt‐60 beams. This could improve access to advanced radiotherapy in low‐ and middle‐income countries. For this system to be clinically viable and to be adapted into the Radiation Planning Assistant (RPA), being developed to offer automated planning services in low‐ and middle‐income countries, it is necessary to commission and validate it in a commercial treatment planning system (TPS). Methods: The novel treatment device considered here employs a cobalt‐60 source and nine compensators. Each compensator is produced by 3‐D printing a thin plastic mold which is then filled on‐demand within the machine with reusable 2‐mm‐diameter spherical tungsten balls. This system was commissioned in the Eclipse TPS and validation tests were conducted with Monte Carlo using Geant4 Application for Tomographic Emission for percentage depth dose, in‐plane profiles, penumbra, and IMRT dose validation. And the American Association of Physicists in Medicine Task Group 119 benchmarking testing was performed. Additionally, compensator‐based cobalt‐60 IMRT plans were created for 46 head‐and‐neck cancer cases and compared to the linac‐based volumetric modulated arc therapy (VMAT) plans used clinically, then dosimetric parameters were evaluated. Beam‐on time for each field was calculated. In addition, the measurement was also performed in a limited environment and compared with the Monte Carlo simulations. Results: The differences in percent depth doses and in‐plane profiles between the Eclipse and Monte Carlo simulations were 0.65% ± 0.41% and 1.02% ± 0.99%, respectively, and the 80%–20% penumbra agreed within 0.46 ± 0.27 mm. For the Task Group 119 validation plans, all treatment planning goals were met and gamma passing rates were >95% (3%/3 mm criteria). In 46 clinical head‐and‐neck cases, the cobalt‐60 compensator‐based IMRT plans had planning target volume (PTV) coverages similar to linac‐based VMAT plans: all dosimetric values for PTV were within 1.5%. The organs at risk dose parameters were somewhat higher in cobalt‐60 compensator‐based IMRT plans versus linac‐based VMAT plans. The mean dose differences for the spinal cord, brain, and brainstem were 4.43 ± 1.92, 3.39 ± 4.67, and 2.40 ± 3.71 Gy, while those for the rest of the organs were <1 Gy. The average beam‐on time per field was 0.42 ± 0.10 min for the 6 MV multi‐leaf‐collimator plans while those for the cobalt‐60 compensator plans were 0.17 ± 0.01 and 0.31 ± 0.01 min at the dose rates of 350 and 175 cGy/min. There was a good agreement between in‐plane profiles from measurements and Monte Carlo simulations, which differences are 1.34 ± 1.90% and 0.13 ± 2.16% for two different fields. Conclusions: A novel compensator‐based IMRT system using cobalt‐60 beams was commissioned and validated in a commercial TPS. Plan quality with this system was comparable to that of linac‐based plans in all test cases with shorter estimated beam‐on times. This system enables reliable, high‐quality plans with reduced cost and complexity and may have benefits for underserved regions of the world. This system is being integrated into the RPA, a web‐based platform for auto‐contouring and auto‐planning. [ABSTRACT FROM AUTHOR]

Nowadays, the irradiation of blood and blood products, as well as sterilization of pharmaceuticals and biological materials used in the medical industry, are being carried out in developed countries and some developing countries. Usually for this purpose, self-contained dry source storage irradiators containing cesium-137 or cobalt-60 gamma ray sources with activity up to 3 kCi are used as blood irradiator facilities. In this research, an attempt was made to use the MCNPX code to perform the calculations related to the nuclear design of a blood irradiator facility using cobalt-60 line sources in two parts of iso-dose curves and shielding according to internationally accepted standards. The dose uniformity ratio inside the irradiation chamber was about 2 and the external dose rate at a distance of 5 cm from the surface of the gamma cell device was about 36 µSv/h and below the allowable limit. The results showed that the iso-dose curves were completely symmetric and the delivered dose increased near the cobalt-60line sources while decreasing as the distance away from the line sources and closer to the cylindrical axis of the irradiation chamber. In addition, the results showed that the designed lead shield with an average thickness of 30 cm easily blocks the gamma rays and in terms of health physics, working with such a blood irradiator will not pose any risk of radiation to employees.

Radioactive cobalt release poses concerns since the attention to radiation safety. In this work, soil and groundwater sampled from the surroundings of the long-distance pipeline of a proposed nuclear power plant were used to assess radiation safety by studying Co(II) adsorption. The Freundlich and Langmuir models fitted the experimental data well. The results indicated that Co adsorption was an entropy-driven, spontaneous, endothermic and chemical process. The adsorption mechanism was mainly the inner-sphere complexation, and CoSO4(aq) contributed to the partially reversible occurrence. This study provided fundamental information about the environmental behaviours and adsorption mechanism of radioactive Co(II) surrounding the effluent pipeline. [ABSTRACT FROM AUTHOR]

A gamma irradiator is a well-developed installation for gamma radiation sterilization. A “shuffle-dwell” mode is preferable for high dose applications. A novel configuration of a shuffle-dwell gamma irradiator is proposed to increase energy utilization and throughput, which would result in higher profitability. While the minimum distance between any irradiation position and each source pencil, the minimum distance between the neighboring irradiation positions and the size of source pencils are kept the same as the current configuration, the irradiation positions and source pencils are rearranged based on the fact that radiation is emitted in an isotropic fashion. The computational results suggest that the proposed configuration requires an 8.7% smaller area and exposes the product to 11.8% more gamma radiation in a 10.7% shorter irradiation time. In other words, the proposed configuration needs a smaller area and shorter irradiation time to have a better performance compared to the current shuffle-dwell gamma irradiator. Note that the claim is based primarily on an analytical calculation. Experimental and manufacturing among other practical considerations will be taken into account in the future work to exhaustively evaluate the performance of the proposed configuration and to compare it with that of the traditional configuration.

In 1984 in the border town of Ciudad Juárez, Mexico, a cobalt radioactive therapy machine was dismantled, melted, and forged into iron materials that created a binational nuclear fallout emergency known as the "cobalt 60 accident," the worst atomic incident in Latin America to date. I study this accident from the perspective of the desert as a site for "wastelanding"—as being a place rendered pollutable and discardable. Ciudad Juárez has been seen as America's backyard, a city hungry for scrap-heap materials. I analyze cultural products, such as a documentary, videos, and two novels that describe the incident, highlighting the corruption and lack of an exhaustive report that confronts the official versions and conspiracy theories. [ABSTRACT FROM AUTHOR]

Background: BCP-Sr-Ag as a bone graft needs to be sterilized. One way of sterilization is to use gamma radiation. Sterilization by gamma radiation requires the correct sterilization dose. Based on ISO 11137 the determination of the sterilization dose through 3 steps: determination bioburden, determination of verification dose, and determination of sterilization dose. Purpose: Determination of gamma radiation sterilization dose on BCP-Sr-Ag bioceramic as bone graft based on ISO 11137 through determination bioburden, determination verification dose, and determination of sterilization dose. Methods: A total 30 samples of 3 different batch BCP-Sr-Ag were determined for bioburden using TSA media. A total 100 samples of BCP-Sr-Ag were irradiated with a verification dose using cobalt-60 gamma source. The 100 samples then tested for sterilization using TSA media to determine the sterilization dose. Results: The average bioburden values of batches 1, 2, and 3 were 56.8; 61.8; and 60.5 CFU. The average value of the whole batch is 59.7 CFU. Based on ISO 11137, the verification dose is 7.4 kGy and the sterilization dose is 20.5 kGy. Conclusion: The average bioburden value of the entire batch was 59.7 CFU. The bioburden value used for verification dose determination is 64.22 CFU so the the gamma radiation sterilization dose is 20.5 kGy. [ABSTRACT FROM AUTHOR]

This article describes a new graphical user interface that uses the PENELOPE Monte Carlo code to calculate dose distributions in materials. It is named PUFFIn, for the Penelope User-Friendly Fast Interface and was developed as an educational and scoping analysis tool for non-experts in radiation modeling. PUFFIn enables the user to visualize and compare the dose distributions in objects (e.g., sterilized healthcare products) irradiated with cobalt-60 gamma-rays, electron beam (E-beam) or X-rays. From such comparisons, the user can determine the most efficient product and/or packaging designs for any given radiation field – whether for conceptual or existing products and packaging. PUFFIn is distributed in a complete, self-contained package of software, including the PENELOPE radiation transport code, a standard graphics package, and a set of simple exercises. The package is available to any user at no cost and requires a minimal amount of training compared to other similar software. PUFFIn's capabilities are described, as well as validation measurements performed at Texas A&M University E-beam facility and the Aerial E-beam Facility in France. • Monte Carlo Simulation for the sterilization of medical products. • User friendly graphical user interface called PUFFIn. • Experimental comparison with simulation results. [ABSTRACT FROM AUTHOR]

Introduction: The study was designed to dosimetrically compare the treatment planning optimization techniques to analyze the equivalence of Co-60 and Ir-192 HDR Brachytherapy sources. Further, the present study planned to analyze the equivalence on the basis of technical, logistical and clinical aspects for both the sources. Methods: Thirty-two patients with confirmed diagnosis of carcinoma cervix were included in the study. Comparative treatment plans were made for three different treatment planning optimization techniques for both the sources Co-60 and Ir-192 i.e. (a) plans with prescription on Point A (Manchester system) with identical dwell position, (b) plans with inverse planning and (c) plans with prescription on HR-CTV with manual optimization. Treatment plans were evaluated on the basis of clinical parameters HR-CTV V200%, V150%, V100%, D95%, D50%, D2cc Bladder, D2cc rectum and point dose on ICRU Rectum and Bladder reference point. Results: For the plans with prescription on Point A with identical dwell position, the average percentage difference were found HR-CTV V200% (6.3%), V150% (5.1%), V100% (1.8%), D2cc rectum (2.3%) and ICRU Rectum reference point (2.1%) and all these parameters were statistically significant for both the sources. For the Plans with inverse planning optimization, these parameters were found significant with average percentage difference HR-CTV V200% (6.1%), V150% (4.9%), D50% (2.1%) and ICRU Rectum reference point (2.3%). For the plans with dose prescription on HR-CTV and manual optimization, most of the average percentage differences were found non-significant and clinical parameters were observed clinically comparable to each other for both the sources. Further, it was also observed that on an average Ir-192 source required only 42% of the treatment time required by Co-60 for the same treatment plan delivery. Conclusion: Among all the three planning techniques, the planning technique with prescription on HR-CTV & manual optimization was found to have comparable clinical quality for both the sources. This analysis revealed that geometry of source placement can overcome the differences in individual source characteristics.

Background: In developing countries like India, cobalt-60 machines still find their applicability, considering the cost and maintenance issues. With a view to deliver conformal treatment plans using teletherapy machines, an automated Multi-Leaf Collimator (MLC) was developed for the existing machines as a retrofit attachment to the collimator assembly without any modifications to the unit. Objective: This study aims to investigate the radiation characteristics of leaf designs incorporated in two add-on prototype MLC systems with respect to the shape of leaf projected at the isocenter plane and the isodose distribution around the target. Besides, the dosimetric characteristics of prototype MLC with divergent leaf design are validated through simulation and experimental measurements.Material and Methods: In this experimental study, two add-on prototype MLC systems were designed and fabricated. The characteristic measurements of leaf designs incorporated in both the prototypes were carried out using Gafchromic films (GAF) and compared with Monte Carlo (MC) simulations. For divergent leaf design, beam profiles were obtained using Monte Carlo simulations which are complemented with the results obtained from measurements of radiochromic films and ionization chamber (IC) profiler. Dosimetric characteristics like radiation field width and beam penumbra were evaluated. Results: The Monte Carlo simulated data are in agreement with experimental data from IC profiler as well as from Radiochromic films. The results of this study are well within acceptable tolerance limits. Conclusion: The prototype MLC system designed for existing telecobalt machines supports its clinical applicability for conformal therapy to better manage treatment in rural areas, which can provide superior cost effective treatments.

We implemented a didactic experiment to study the angular correlation between the two gamma rays emitted in typical 60Co radioactive decays. We used two NaI(Tl) scintillators, already available in our laboratory, and a low-activity 60Co source. The detectors were mounted on two rails, with the source at their center. The first rail was fixed, while the second could be rotated around the source. We performed several measurements by changing the angle between the two scintillators in the range from 90° to 180°. Dedicated background runs were also performed, removing the source from the experimental setup. We found that the signal rate increases with the angular separation between the two scintillators, with small discrepancies from the theoretical expectations. [ABSTRACT FROM AUTHOR]

Background: Adjuvant radiotherapy after mastectomy or breast conserving surgery (BCS) is the standard of care for majority of patients with breast cancer. This is however associated with mucosal and epidermal toxicity of organs at risk (OARs). Breast cancer patients are exposed to a plethora of wrong perceptions, misinformation and myths concerning the usefulness and adverse effects of radiotherapy. There is paucity of literature on the incidence and severity of radiation-induced acute toxicities experienced by patients with breast cancer in Ghana., Aim: To assess the occurrence and severity of four main acute radiation-induced toxicities among female breast cancer patients treated with external beam radiotherapy at a major cancer treatment centre in Ghana., Methods: Data on the occurrence of acute toxicities among patients was collected from patients' medical records, through a semi-structured questionnaire and via weekly clinical assessments. The Common Terminology Criteria for Adverse Events (CTCAE) grading scale (version 4.0) was used to grade the severity of these toxicities. Descriptive and inferential statistics using an independent two-sampled t-test (two-tailed), one-way analysis of variance (ANOVA), Pearson's Chi-square and Fisher's exact tests were performed., Results: Dermatitis, fatigue, pharyngitis, and breast (chest) pain were the radiation toxicities found among the breast cancer patients undergoing treatment on the two machines. The mean predominant radiation doses associated with the onset of dermatitis, fatigue, pharyngitis, and chest pain in the breast cancer patients were 22.32 Gy, 22.48 Gy, 13.59 Gy, and 19.27 Gy respectively for treatment with a statistically significant (p = 0.0173). Radiation dermatitis was the most dominant acute radiation toxicity recorded, and its incidence and severity. The range of Fisher's p-values (0.689-0.999) between the acute radiation toxicities with both machines revealed no statistical significance., Conclusion: Radiation dermatitis was the dominant acute toxicity, both in incidence and severity for patients treated. There was no statistical significance in the incidence and severity of acute radiation side effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Dosimetric and clinical comparison of two cohorts of Iridium-192 (Ir-192) and Cobalt-60 (Co-60) high-dose-rate brachytherapy (DR-BT) boost for localized prostate cancer. Patients with localized prostate cancer receiving either Ir-192 or Co-60 high-dose-rate brachytherapy (HDR-BT) boost in combination with external beam radiotherapy (EBRT) in the period of 2002–2019 were evaluated for dosimetric differences, side effects, biochemical relapse-free survival (bRFS), metastasis-free survival (MFS), and overall survival (OS). EBRT, delivered in 46 Gy (DMean) in conventional fractionation, was followed by two fractions HDR-BT boost with 9 Gy (D90%) 2 and 4 weeks after EBRT. Genitourinary (GU)/gastrointestinal (GI) toxicity were evaluated utilizing the Common Toxicity Criteria for Adverse Events version 5.0 and biochemical failure was defined according to the Phoenix definition. A total of 338 patients with a median follow-up of 101.8 (IQR 65.7–143.0) months were evaluated. At 10 years the estimated bRFS, MFS, and OS in our patient sample were 81.1%/71.2% (p=.073), 87.0%/85.7% (p=.862), and 70.1%/69.7% (p=.998) for Ir-192/Co-60, respectively. Cumulative 5-year late grade ≥2 GU toxicity was 20% for Ir-192 and 18.3% for Co-60 (p=.771). Cumulative 5-year late grade ≥2 GI toxicity was 5.8% for Ir-192 and 4.6% for Co-60 (p=.610). Grade 3 late GU side effects were pronounced in the Ir-192 cohort with 8.1% versus 1.4% in the Co-60 cohort (p=.01), which was associated with significantly lower dose to the organs at risk in the Co-60 cohort. PTV D90% was 9.3 ± 0.8 Gy versus 9.0 ± 1.1 Gy (p=.027) for Ir-192 versus Co-60. PTV V100% and PTV V150% were not significantly different between both cohorts. Co-60 brachytherapy sources are an effective alternative to Ir-192 in combined prostate HDR-BT boost + EBRT. [ABSTRACT FROM AUTHOR]

Pinhão is highly perishable due to its high water activity, being easily affected by fungi during storage and also susceptible to infestation by larvae. This seed is usually marketed in the pinhão cones itself, or bulk threshed, and packed in plastic bags, chilled or ground frozen. Pinhão conservation and industrialization techniques should be developed to promote its commercialization and consumption at other times of the year, besides the seasonal period, encouraging its sustainable production, extraction and commercialization, considering its essentially extractive character. The objective of this study was to evaluate the conservation of pinhão by the use of gamma radiation and refrigeration. The pinhões were irradiated with a cobalt–60 source at a dose rate of 1 kGy. A non-irradiated sample was used as a control. The pinhões were packed in high-density polyethylene bags and stored at ambient temperature and refrigerated at 4 ºC, during 90 days. Pinhões were evaluated for weight loss, acidity, reducing sugars, vitamin C, firmness, color, total phenolic compounds, antioxidant activity and microbiological analyzes. The isolated use of gamma radiation was not effective for the maintenance of the evaluated parameters. However, when used in conjunction with refrigerated storage, it reduced the growth of aerobic fungi, as well as mesophilic and psychrotrophic microorganisms. The isolated use of refrigeration showed a reduction in weight loss, reducing sugars and an increase in vitamin C content and antioxidant activity. Thus, to increase the benefits, we suggest evaluating higher doses of radiation as a function of the thick pinhão shell.

The Cobalt-60 source used at the Tunisian Gamma Irradiation Facility is nearing the end of its useful life. Due to the current low dose rates, the irradiation process takes a long time. To address exposure time and cost issues, source racks need to be reloaded to improve the quality of the exposure process. This work aims to find the optimal new configuration for future reloading of the Cobalt-60 source rack and to evaluate the dose rate distribution in the vicinity of the Irradiator and the Dose Uniformity Ratio (DUR) in a dummy product. When keeping old pencils, the optimal configuration will need to be adjusted to accommodate the new Cobalt-60 pencils. The replenishment method developed using FLUKA-based Monte Carlo code involved the addition of six new pencils: three in the upper top (outer) holder of the source rack and three in the lower bottom (inner) source holder. The spatial distribution of dose rates in the vicinity of the source rack before and after reloading was evaluated. For the radiation processing, the maximum and minimum absorbed dose in the dummy product were estimated to calculate the DUR value. The DUR value for a single-use medical product is about 2.5. The results obtained before and after reloading show that the spatial distribution of the dose rate is uniform for the proposed configurations, and has a value of approximately 0.4 kGy/h after reloading at the conveyor belt location. [ABSTRACT FROM AUTHOR]

Purpose: To report vaginal cuff brachytherapy (VCB) dosimetry parameters and clinical outcomes of patients with localized endometrial cancer treated with adjuvant high-dose-rate (HDR) brachytherapy using a cobalt-60 (60Co) source. Material and methods: Between 2011 and 2017, we identified patients with endometrial cancer treated with surgery and adjuvant VCB. Dosimetry variables analyzed included D2cc, D1cc, and D0.1cc for organs at risk (OARs) and distance from cylinder surface to 150% and 200% isodose line in vaginal mucosa. Local relapse (LR), regional relapse (RR), distant metastasis (DM), progression-free survival (PFS), and overall survival (OS) were analyzed using Kaplan-Meier, and log-rank test was applied to assess differences between groups. Toxicity evaluation was tested for possible cross-correlation within dosimetric parameters using Pearson r test and stepwise multivariate linear regression. Results: We identified 93 suitable patients. Mean age at diagnosis was 66 years (range, 45-85 years). Most patients had endometrioid adenocarcinoma (61.3%), followed by papillary-serous carcinoma (11.8%). 71% of patients presented with FIGO stage I (35.5% IA and 35.5% IB), 11.8% were stage II, and 17.2% were stage III. Adjuvant external beam radiotherapy (EBRT) (range, 46-50.4 Gy) was used in 53.8% of patients, and adjuvant chemotherapy in 38.7%. Median follow-up was 39 months (range, 5-84 months). Three-year OS and PFS were 87.5% and 85.5%, respectively. LR was seen in 2.2% of cases, RR in 7.5%, and DM in 12.9%. Mean rectum D2cc/D0.1cc were 88.1% and 116%, and mean bladder D2cc/D0.1cc were 79.2% and 103.2%, respectively. The most common acute toxicity was vaginal mucositis (8.9% = G2), and the most frequent chronic toxicity was vaginal stenosis (25.3% = G1). Conclusions: Adjuvant high-dose-rate VCB with 60Co source for patients with endometrial cancer is well tolerated, with clinical and toxicity outcomes comparable to those reported with iridium-192 (192Ir) source. [ABSTRACT FROM AUTHOR]

The sorption kinetics of microamounts of Co(II) ions by the Termoxid 35 sorbent in a constant ionic strength chloride–acetate solution with and without the presence of natural humic acids (HAs) was studied using the finite volume method with sorbate recirculation. Detailed data on the real-time sorption of the 60Co radionuclide by the sorbent were obtained based on the rate of solution passing through the sorbent, pH, temperature, and HA concentration. The mixed-diffusion model of the Co(II) sorption kinetics, which includes successive stages of film and gel diffusion in the macro-micropores of the sorbent grain, the most statistically accurately and adequately simulates the data obtained. The coefficients of film (β, m/s) and gel (Dg, m2/s) diffusion do not depend on solution pH and HA concentration. The average value of Dg is (6.0 ± 4.5) × 10–10 m2/s, the activation energy of gel diffusion is 20.7 ± 10.0 kJ/mol at pH 7.5. The found values ​​are close to the Co2+ self-diffusion parameters in ultradilute aqueous solutions. A conclusion was made about the possibility of efficient sorption of Co(II) from natural aqueous solutions by the Termoxid 35 sorbent in the presence of humic acids. [ABSTRACT FROM AUTHOR]

Production of high specific activity (HSA) 60Co has recently resumed at the Advanced Test Reactor (ATR) at the Idaho National Laboratory. The technical steps of performing in-canal assay of HSA 60Co targets at the ATR are described herein. The HSA targets are assayed on a regular basis, between cycles at the ATR, in order to assess the progress of activation. The targets are also assayed at the conclusion of the irradiation in order to provide activity estimates for the distributor and to be used for safety and shipping evaluations. These target assay activities must take place in the ATR canal to provide sufficient radiological shielding. A specialized assay fixture is used in conjunction with custom 60Co radiation standards to assess the irradiated target. The specific activity of each irradiated target was determined by first measuring the 60Co standards to determine a sensitivity factor. Then, each irradiated target was measured, and the integrated measurement was multiplied by the sensitivity factor to determine the total activity of the irradiated target. Finally, a correction factor was determined to adjust the reported activity, accounting for differences in the physical geometries of the standards and targets. These methods were used to accurately assay the gross activity of nine irradiated 60Co targets, two of which were delivered to the distributor where confirmatory hot-cell assays were performed verifying the accuracy of the in-canal assay method. [ABSTRACT FROM AUTHOR]

Pinhão is highly perishable due to its high water activity, being easily affected by fungi during storage and also susceptible to infestation by larvae. This seed is usually marketed in the pinhão cones itself, or bulk threshed, and packed in plastic bags, chilled or ground frozen. Pinhão conservation and industrialization techniques should be developed to promote its commercialization and consumption at other times of the year, besides the seasonal period, encouraging its sustainable production, extraction and commercialization, considering its essentially extractive character. The objective of this study was to evaluate the conservation of pinhão by the use of gamma radiation and refrigeration. The pinhões were irradiated with a cobalt-60 source at a dose rate of 1 kGy. A non-irradiated sample was used as a control. The pinhões were packed in high-density polyethylene bags and stored at ambient temperature and refrigerated at 4 °C, during 90 days. Pinhões were evaluated for weight loss, acidity, reducing sugars, vitamin C, firmness, color, total phenolic compounds, antioxidant activity and microbiological analyzes. The isolated use of gamma radiation was not effective for the maintenance of the evaluated parameters. However, when used in conjunction with refrigerated storage, it reduced the growth of aerobic fungi, as well as mesophilic and psychrotrophic microorganisms. The isolated use of refrigeration showed a reduction in weight loss, reducing sugars and an increase in vitamin C content and antioxidant activity. Thus, to increase the benefits, we suggest evaluating higher doses of radiation as a function of the thick pinhão shell. [ABSTRACT FROM AUTHOR]

We describe the absolute and per capita numbers of megavoltage radiotherapy machines (MVMs) in Western Africa from 1969 to 2019. Western Africa was defined in accordance with the United Nations' delineation and inclusive of 16 countries. A literature search for publications detailing the number of cobalt-60 machines (COs) and linear accelerators (LINACs) in radiotherapy centres was carried out. Population data from the World Bank Group and crude cancer rates from the International Agency for Research on Cancer were used to calculate ratios of million persons per MVM and MVMs per 1000 cancer cases. The numbers of MVMs in Western Africa in 1969, 1979, 1989, 1999 and 2009 were zero, two, three, six and nine, respectively. In 2019 there were 22 MVMs distributed across Ghana (five), Côte d'Ivoire (two), Mali (one), Mauritania (two), Nigeria (nine) and Senegal (three). Nine countries (56.3%) had no history of external beam radiotherapy (EBRT). The largest increase in absolute EBRT capacity occurred from 2017 to 2019, during which 13 MVMs were commissioned. The largest decrease in EBRT capacity occurred from 2015 to 2017, during which four LINACs and three COs were rendered non-operational. The ratio of million persons per MVM improved from 67.0 in 1979 to 17.8 in 2019. As of 2019, there was 0.09 MVM per 1000 cancer cases. Western African nations have experienced an increase in the absolute number of MVMs and per capita radiotherapy capacity during the last 50 years, especially in the last decade. As non-functional LINACs contributed to a temporary decline in the EBRT infrastructure, dual use of CO/LINAC technologies may act to promote the availability of EBRT treatment in centres with capacity for multiple MVMs. • Seven of 16 Western African countries have a history of external beam radiotherapy capacity. • The number of megavoltage machines in Western Africa increased from 0 in 1969 to 22 in 2019. • Three countries opened radiotherapy centres after 2009, accounting for nearly 25% of megavoltage machines present in 2019. • The ratio of million persons per megavoltage machine improved from 67.0 million in 1979 to 17.8 million in 2019. [ABSTRACT FROM AUTHOR]

Background: In developing countries like India, cobalt-60 machines still find their applicability, considering the cost and maintenance issues. With a view to deliver conformal treatment plans using teletherapy machines, an automated Multi-Leaf Collimator (MLC) was developed for the existing machines as a retrofit attachment to the collimator assembly without any modifications to the unit. Objective: This study aims to investigate the radiation characteristics of leaf designs incorporated in two add-on prototype MLC systems with respect to the shape of leaf projected at the isocenter plane and the isodose distribution around the target. Besides, the dosimetric characteristics of prototype MLC with divergent leaf design are validated through simulation and experimental measurements. Material and Methods: In this experimental study, two add-on prototype MLC systems were designed and fabricated. The characteristic measurements of leaf designs incorporated in both the prototypes were carried out using Gafchromic films (GAF) and compared with Monte Carlo (MC) simulations. For divergent leaf design, beam profiles were obtained using Monte Carlo simulations which are complemented with the results obtained from measurements of radiochromic films and ionization chamber (IC) profiler. Dosimetric characteristics like radiation field width and beam penumbra were evaluated. Results: The Monte Carlo simulated data are in agreement with experimental data from IC profiler as well as from Radiochromic films. The results of this study are well within acceptable tolerance limits. Conclusion: The prototype MLC system designed for existing telecobalt machines supports its clinical applicability for conformal therapy to better manage treatment in rural areas, which can provide superior cost effective treatments. [ABSTRACT FROM AUTHOR]

Background: High Dose Rate (HDR) brachytherapy sources with high photon energy have been widely used in treating tumors. Dosimetric parameter of these brachytherapy sources should be determined according to the AAPM TG-43 recommendation. Gafchoromic films are reliable tools for this evaluation. Objective: The aim of this study is to evaluate and compare dose accuracy of the two-brachytherapy sources in a dedicated phantom.Material and Methods: In this analytical study, two common sources, including Cobalt and Iridium, were loaded into the dedicated phantom. The two-dimensional dose distribution around the source was calculated by TPS system for certain activities and geometries around the sources. Then, the experimental dose measured by Gafchromic film dosimetry was reported for different angles ranging from 0 to 180 degrees. Results: The difference between calculated and measured doses was less than 6 percent (-5 to +6 percent) for all of the channels and angles. These errors are smaller and mainly more than zero (Dfilm>DTPS) for angles less than 20 and larger than 110 degrees. There is no statistically significant discrepancy in dose calculation by treatment planning system. Conclusion: Although the estimated error in dose calculation is not significant, there is still an opportunity to increase the treatment precision. The correlation between the error and the angle should be considered in further plans of brachytherapy. The present study showed comparable errors compared to results of other research studies.

The purpose of this work is to determine a date for the next reloading operation of the panoramic gamma irradiator of the Moroccan National Institute of Agronomic Research (NIAR) by studying the variation with time of the dosimetric mapping at the inside the irradiation casemate between 2021 and 2030. The NIAR irradiator is a gamma irradiator currently contains 8 cobalt-60 pencils used to develop Moroccan agriculture by doing research in this field by ionization of agricultural products. Monte Carlo simulation via the GEANT4 code was used as a tool to establish the distribution of isodose in the irradiation room due to its important role in meeting the dosimetric requirements for this type of facilities. The results show that from January 1, 2024, serious measures must be taken to arrange a date for the NIAR irradiator reloading operation not later than 2027. [ABSTRACT FROM AUTHOR]

Carolina laurel cherry (Prunus caroliniana) is native to the U.S. southeastern coastal plain from North Carolina westward to eastern Texas. The species has been planted extensively in the southeast as an ornamental tree or hedge. Unfortunately, carolina laurel cherry naturalizes readily and is now found in a variety of habitats, both natural and disturbed. Flowering occurs in the late winter/early spring before new leaves emerge and fruit ripens in the fall/winter. Fruit is eaten by migratory birds and seed is dispersed. Seedlings readily germinate in the understory of forests and landscapes in the spring. As there are a limited number of cultivars available, selections with improved form and sterility are needed for the landscape trade. In 2008, seed was collected and treated with Cobalt-60 gamma irradiation at rates ranging from 0 to 150 Gy. The lethal dose killing 50% of the seedlings (LD50) was between 50 and 100 Gy. Three sterile plants were selected in 2012 from the M1 (first generation of mutagen-treated seedlings) population totaling 62 seedlings. M2 (second-generation seedlings from M1 parents) seed was collected Fall 2012, and 1509 seedlings were grown to flowering size in containers. In 2014–15, 120 seedlings that showed no fruit production were planted in the field in Watkinsville, GA, for further evaluation. Ratings on field-grown plants in Dec. 2017 and 2018 showed that 73% and 78% of the plants, respectively, produced no fruit, whereas the remaining plants had minimal to heavy fruit set. Because carolina laurel cherry is andromonoecious, production of male and bisexual flowers was evaluated on 17 selections in 2018. Of 500 flowers evaluated per selection, the number of male flowers per plant ranged from 22 to 415 (4.4% to 83%). The number of racemes with all-male flowers on each selection ranged from 1 to 32. There were no significant correlations between the number of male flowers or number of all-male flowered racemes per plant and production of fruit. Approximately 5% of M2 seedlings remain seedless after 6 years of growth.

Context: The conventional concomitant chemoradiotherapy (CCRT) is the standard treatment for locally advanced non-small cell lung cancer. Accelerated CCRT results in shortening of overall treatment time which can contribute in controlling accelerated tumor repopulation. The increase in tumor control probability (TCP) can be expected with no or little effect on late normal tissue injury for a given total dose. Aim: The aim of this study was to compare the disease response, toxicity profile, quality of life (QoL), and overall survival in accelerated versus conventional CCRT. Subjects and Methods: Total 42 patients were randomized into two groups – study group (n = 21): Accelerated CCRT, radiation was given as 6 fractions per week (60 Gy/5 weeks/30#) with injection cisplatin 20 mg/m2 intravenous (iv) days 1–5 and days 29–33 + injection etoposide 50 mg/m2 iv days 1–5 and days 29–33 and control group (n = 21): Conventional CCRT, radiation was given as 5 fractions per week (60 Gy/6 weeks/30#) along with the same chemotherapy. External beam radiation therapy was delivered by cobalt-60 machines. Results: The overall response rate (complete and partial response) for all patients was 66.6%. In the control group, it was 66.2%, and in the study group, it was 66.6%. Grade ≥II pulmonary, hematological, and esophageal toxicities were seen in 57%, 43%, and 24% in patients of the control group and 53%, 53%, and 33% in the study group, respectively. In QoL analysis, maximum improvement was noted for hemoptysis, arm/shoulder pain, dyspnea, and chest pain in both the groups. Statistical Analysis Used: The data were analyzed by Student's t-test and Chi-square test. P < 0.05 was taken as statistically significant. Conclusion: As response rates and disease progression were similar in both the groups, accelerated chemoradiotherapy can be considered as an alternate therapy, especially in high-volume centers. [ABSTRACT FROM AUTHOR]

The study was conducted to use different microbial species isolated from low-level radioactive wastewaters (up to 2 mSv) for removing non-radioactive (Co(II)) and radioactive cobalt (Cobalt-60) from waste solutions using different immobilization techniques; beads and thin film. Simple and innovate technique was used to prepare calcium alginate thin film. The isolated bacterial species investigated were Bacillus haynesii and Bacillus aerius while fungal species were; Aspergillus foetidus, Aspergillus parasiticus, and Penicillium oxalicum. The bacterial species were immobilized in wet form, while the fungal species were immobilized in wet and dry forms using sodium alginate gel. Screening of bacterial and fungal species in free and immobilized shapes for Co(II) and Cobalt-60 removal percent and capacity was studied. Moreover, the efficient immobilized weight could be used in the different immobilization shapes was investigated. Batch experiments were used to determine the optimum environmental conditions for cobalt removal by the immobilized beads or thin film. Scanning electron microscopy was done to observe the surface changes. However, the energy-dispersive X-ray analysis results indicated the accumulation of cobalt ions on the surface. The immobilized dry P. oxalicum beads showed higher Cobalt-60 removal percent about 79.3% as compared to all other immobilized bacteria and fungi biomasses. The statistical analysis using Statistical Package of Social Science (SPSS) indicated that the studied bacterial species had significant high means with (p-value < 0.05) for the removal efficiency either free or immobilized than studied fungal species. Also, there was a significant high means for immobilization in thin film shape than immobilization in beads for removal of Co(II) in both bacteria and fungi. In contrast, the immobilized beads had a significant high mean for Cobalt-60 removal in both bacteria and fungi. [ABSTRACT FROM AUTHOR]

The applications that cover the use of ionizing radiation are numerous, very diverse and belong to several fields of activity such as, the medical and agricultural fields etc. The aim of this work is to highlight an application of decorative glass coloring by gamma radiation. Crystal white glass cups are placed on small rotating tables and subjected to exposure to gamma radiation from the cobalt-60 gamma irradiator of the National Institute of Agronomic Research (INRA-Morocco / Tangier) for doses between 0 and 1.5 KGy. The results obtained show the variation in the color of glass between light brown to dark brown depending on the absorbed dose.

The development of gamma ray-mutated rice lines is a solution for introducing genetic variability in indica rice varieties already being used by farmers. In vitro gamma ray (60Co) mutagenesis reduces chimeras and allows for a faster selection of desirable traits but requires the optimization of the laboratory procedure. The objectives of the present work were sequencing of matK and rbcL, the in vitro establishment of recalcitrant rice embryogenic calli, the determination of their sensitivity to gamma radiation, and optimization of the generation procedure. All sequenced genes matched perfectly with previously reported matK and rbcL O. sativa genes. Embryogenic calli induction improved using MS medium containing 2 mg L−1 2,4-D, and regeneration was achieved with MS medium with 3 mg L−1 BA and 0.5 mg L−1 NAA. The optimized radiation condition was 60 Gy, (LD20 = 64 Gy) with 83% regeneration. An immersion system (RITA®, Saint-Mathieu-de-Tréviers, France) of either 60 or 120 s every 8 h allowed systematic and homogeneous total regeneration of the recalcitrant line. Other well-known recalcitrant cultivars, CR1821 and CR1113, also had improved regeneration in the immersion system. To our knowledge, this is the first study reporting the use of an immersion system to allow for the regeneration of gamma-ray mutants from recalcitrant indica rice materials.

Purpose: To record and report dosimetric and clinical outcomes of interstitial brachytherapy using cobalt-60 (60Co) source in cervical cancer. Material and methods: Seventy patients who underwent external beam radiotherapy with dose of 45 Gy in 25 fractions, followed by interstitial brachytherapy (ISBT) 6.5 Gy x 4 fractions were included into this study. The ISBT applicators were inserted under combined spinal and epidural anesthesia. Computed tomography (CT) simulation was performed and axial CT images were transferred to treatment planning system. High-risk clinical target volume (CTVHR) and organs at risks (OARs) were contoured. Four fractions of 6.5 Gy were prescribed to CTVHR using inverse planning technique. Patients were followed-up for 3 years. Dosimetric parameters and clinical outcomes were recorded and compared with available literature. Results: Seventy patients with FIGO stage IIB-IVA were included in the study. The median EQD2 of 2 cm³ of bladder, rectum, sigmoid and D90 CTVHR were 70 Gy (53-75 Gy), 64 Gy (51-71 Gy), 48 Gy (44-72 Gy), and 77 Gy (70-86 Gy), and dose homogeneity index (DHI), dose non-uniformity ratio (DNR), coverage index (CI), overdose volume index (OI), and conformal index (COIN) were 0.58 (0.39-0.78), 0.42 (0.22-0.61), 0.87 (0.59-0.97), 0.19 (0.09-0.30) and 0.74 (0.52-0.85), respectively. Local control rate at 2 years was 87.14%. Eight patients had local recurrence and one patient had lung metastasis. Also, two patients with local recurrence had recto-vaginal fistula. Two patients had grade 2 proctitis (2.8%) and one patient developed grade 3 proctitis (1.4%). There was no grade 2 or higher bladder toxicity. Conclusions: The dosimetric parameters, local control and toxicities of high-dose-rate interstitial brachytherapy in cervical cancer patients treated by 60Co radioactive source are similar, compared to available literature using iridium-192 (192Ir) source. [ABSTRACT FROM AUTHOR]

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Background: High Dose Rate (HDR) brachytherapy sources with high photon energy have been widely used in treating tumors. Dosimetric parameter of these brachytherapy sources should be determined according to the AAPM TG-43 recommendation. Gafchoromic films are reliable tools for this evaluation. Objective: The aim of this study is to evaluate and compare dose accuracy of the two-brachytherapy sources in a dedicated phantom. Material and Methods: In this analytical study, two common sources, including Cobalt and Iridium, were loaded into the dedicated phantom. The two-dimensional dose distribution around the source was calculated by TPS system for certain activities and geometries around the sources. Then, the experimental dose measured by Gafchromic film dosimetry was reported for different angles ranging from 0 to 180 degrees. Results: The difference between calculated and measured doses was less than 6 percent (-5 to +6 percent) for all of the channels and angles. These errors are smaller and mainly more than zero (Dfilm>DTPS) for angles less than 20 and larger than 110 degrees. There is no statistically significant discrepancy in dose calculation by treatment planning system. Conclusion: Although the estimated error in dose calculation is not significant, there is still an opportunity to increase the treatment precision. The correlation between the error and the angle should be considered in further plans of brachytherapy. The present study showed comparable errors compared to results of other research studies. [ABSTRACT FROM AUTHOR]

An automatic control system is one of the most important parts of an irradiation facility. The level of this control is always maintained to comply with safety procedures during routine work in this field. Also sometimes it is limited to the minimum level of regulation required due to economical aspects; some commercial systems are generally made by manufacturers of industrial facilities and considered affordable by irradiators. In some cases specific irradiation facilities tailor their control systems to their needs. For this kind of irradiator the control system can be developed and upgraded according to personal and industrial experiences. These upgrading procedures are also used by others to develop their systems. The objective of this paper is to share a local experience in upgrading security, safety systems and the use of cobalt-60 for the irradiator. It is a composite experiment at SIBO INRA/Tangier, Morocco and concerns the: (i) upgrade of cobalt-60 in a temporary pool in the SIBO irradiator in Tangier. This operation was conducted in collaboration with the International Atomic Energy Agency (IAEA) and was a success story of 2014 according to the general conference of IAEA; (ii) safety and technical upgrade of the system in the SIBO irradiator made in collaboration with IAEA; (iii) installation and upgrade of the security system in accordance with the Global Threat Reduction Programme (GTRP) to reduce the threat of a Radiological Dispersal Device (RDD) in collaboration with The United States Department of Energy’s National Nuclear Security Administration (NNSA).

In recent years, the demand for the radioactive isotope of Cobalt-60 has grown, mostly because of its extensive applications in sterilization of medical equipment and treatment of tumors. Its production for now is mostly carried out in CANDU or RMBK reactors. However, this work analyzed the pressurized water reactor based on the Westinghouse AP1000 design, as PWRs are now considered a possible new Co-60 supplier. Specifically, three different fuel assemblies were investigated, with varying types and number of neutron burnable absorbers used and five fuel enrichments. The Co-59 was inserted as a rod with thin aluminum coating into 4, 6 or 8 guide tubes in the assembly. All calculations were performed using the SERPENT2 Monte Carlo Neutron Transport code with fuel depletion capability. The results have shown that the increased number of cobalt rods indeed led to a greater amount of Co-60 produced, however, did not affect an average per rod but reduced available reactivity. A dependence on the fuel enrichment of the mass of Co-60 produced was observed, while neutron absorbers, on the other hand, did not significantly change the production rate, which implies that the rods could possibly be inserted into various types of assemblies. [ABSTRACT FROM AUTHOR]

Abstract An altitude-based background correction strategy was developed for use in the application of pattern recognition methods to the classification of gamma-ray spectra collected during airborne surveys. Application of this methodology helped to suppress the background spectral variation that serves to obscure the photopeaks associated with low levels of gamma-ray emission. The correction method was implemented by optimizing a database of background gamma-ray spectra collected at various locations and altitudes. Given this background database, a field-collected spectrum was corrected by performing linear regression onto a background spectrum from the database at a matching altitude. The residuals about the regression fit were then digitally filtered and submitted to nonparametric linear discriminant analysis for the purpose of computing classification models for targeted radioisotopes. The resulting classifiers were applied to predict the presence or absence of specific radioisotope signatures in data acquired during airborne surveys. Employing data provided by the U.S Environmental Protection Agency Airborne Spectral Photometric Environmental Collection Technology (ASPECT) program, classification models were computed to detect the presence of cesium-137 (137Cs) and cobalt-60 (60Co). The optimized classifiers were tested over 12 diverse locations, with nine of these data sets containing the target radioisotopes. Correct classification percentages of 99.4% and 99.8% were obtained for the 137Cs and 60Co classifiers, respectively, on the basis of comparisons to visual inspections of the corresponding spectra. Highlights • Altitude-based background correction for gamma-ray spectra. • Enhances pattern recognition of radioisotopes in airborne surveys. • Automated detection of 137Cs and 60Co. • Methodology tested with aerial surveys of 12 independent field sites. • Ability to detect weak radioisotope signals is improved. [ABSTRACT FROM AUTHOR]

Abstract Soil transport on fully vegetated land surfaces is typically detachment limited. Rates of soil and nutrient transport, and ultimately long-term landscape evolution, are controlled by processes that supply soil material for entrainment and transport. Despite their on-going nature, many such processes operate at low rates and have not been subject to detailed investigation. We present preliminary findings from a prototype tracing approach to quantify one such process; namely to determine the relative mobility of sediment from earthworm casts on a fully vegetated hillslope surface. A 0.6 ∗ 0.5 m bounded area of pasture was prepared and fifteen intact earthworm casts representing 203 g of soil were labelled with an estimated 216 Bq of caesium-134 (134Cs) activity and evenly distributed across the upslope half of the plot, 0.3–0.6 m from the downslope outlet. A further 15 intact casts representing 190.7 g of soil were labelled with 224 Bq of cobalt-60 (60Co) activity and distributed between 0.3 and 0.0 m from the same outlet. All labelled casts were exposed to natural weather events over 76 days, during which time 186.3 mm of rainfall generated 16 runoff samples. A mass balance was used to partition labelled sediment from the unlabelled material. A total of 27.17 g of 60Co-labelled casts, equivalent to 14.2% of the original mass deployed, was recovered from a distance of ≤0.3 m from their original locations. In contrast, 8.77 g of 134Cs-labelled casts, equivalent to 4.3% of the original mass deployed, was recovered from a distance ≥0.3 m from their original locations. Some runoff-derived samples recorded an over-enrichment of radionuclide material, which suggests that intact casts may sorb more material than the original assumption predicts. Ways in which sorption can be more accurately quantified to improve the accuracy of the tracing approach are outlined. Graphical abstract Unlabelled Image Highlights • Earthworm casts have been implicated as a sediment-source on agricultural land. • A procedure was developed to trace dispersed sediment from earthworm casts. • Travel distances were considerably longer than previously reported. • Sediment remains mobile for at least a few months after initial production. [ABSTRACT FROM AUTHOR]

Background: Recent investigations demonstrate a strong potential for cobalt-60 (Co-60)-based teletherapy. The influence of the lower energy and penetration of a cobalt-60 beam compared with linear accelerator beams is negligible for intensity-modulated radiotherapy. Purpose: The aim of this research is to investigate source head fluence modulation in cobalt-60 teletherapy by using a three-dimensional (3D) physical compensator and secondary collimator jaw motion. Materials and methods: The Oncentra treatment planning system was used to develop three hypothetical plans by secondary collimator jaw motion. A clinical MDS Nordion Equinox 80 cobalt-60 teletherapy unit was used to acquire conventional water phantom beam characteristics. Fluence modulation experiments were executed at 5·0 cm depth in a PTW universal intensity-modulated radiation therapy (IMRT) verification phantom using calibrated Gafchromic external beam therapy 2 (EBT2) and RTQA2-1010 film batches. Gafchromic EBT2 film was used to sample intensity maps generated by secondary collimator jaw motion, yet Gafchromic RTQA2-1010 film sampled maps from the 3D physical compensator. The solid-state drives used were 75·0 and 74·3 cm for the Gafchromic EBT2 and Gafchromic RTQA2-1010 film measurements. Results: A 2D gamma index analysis was coded to compare EBT2 film measurements with Digital Imaging and Communications in Medicine data. This analysis was also used to verify film measurements versus Monte-Carlo simulations. Conclusion: Lateral beam profiles generated from water phantom measurements were used to establish source head fluence modulation on the film measurements. The source head fluence of a cobalt-60 teletherapy beam could be modulated by secondary collimator jaw motion and using a 3D physical compensator. [ABSTRACT FROM AUTHOR]

Azuki bean beetle, Callosobruchus chinensis (L.) (Coleoptera: Bruchidae), is a field-to-storage pest of legumes and its females produce sex pheromone components with two isomers: (2 Z ,6 E)-7-ethyl-3,11-dimethyl-2,6,10-dodecatrienal (2 Z -homofarnesal) and (2 E ,6 E)-7-ethyl-3,11-dimethyl-2,6,10-dodecatrienal (2 E -homofarnesal). Two-day-old virgin adults were treated with different doses (0, 200, 300, 400, 500, and 600 Gy) of gamma radiation and the effects on adult survivorship, fecundity, sterility, and pheromone production were studied. The longevity of both sexes and female fecundity were dose dependently affected by the gamma irradiation revealing that the fecundity was more reduced when the female adults were irradiated. Adults of both sexes were totally sterilized by the doses of gamma radiation tested in this study as depicted by the null hatchability of the laid eggs. The results from analyses by gas chromatography–mass spectrometry for solid phase micro-extraction revealed that both of the female sex pheromone components were significantly reduced by 300 Gy. Though significantly less, there was release of some amount of pheromone components by the irradiated female azuki bean beetles revealing the possibility of pheromonal attraction of males to the irradiated females. It is a pre-requisite for the successful sterile insect technology that the sterility of azuki bean beetle is induced without the total disruption of the calling behavior. [ABSTRACT FROM AUTHOR]

In this study, novel surface-modified hematite nanoparticles (α-Fe2O3 NPs) were prepared at 250 °C using iron(III) chloride hexahydrate (FeCl3·6H2O) and oleic acid (C18H34O2) as raw materials for the removal of cobalt-60 radiocations from aqueous solutions by hydrothermal method. α-Fe2O3 NPs were characterized by X-ray diffraction, Fourier transform infrared (FT-IR), scanning electron microscope, transmission electron microscopy and Brunauer-Emmett-Teller. According to the results, the average diameter and length of the synthesized α-Fe2O3 nanorods varied in the range of 30-60 and 400-700 nm, respectively, when the specific surface area was 31.29 m2/g. In batch experiments, the effect of some variables such as pH (2-10), adsorbent weight (0.5, 1, 1.5, 2.5, 3.75 and 5 mg in 25 mL solution), initial concentration of cobalt-60 radiocations (1, 10, 25, 50, 75 and 100 mg/L), temperature (25, 30, 35, 40 and 45 °C) and contact time (1, 2, 3, 4, 5 and 6 h) was investigated at 120 rpm. The optimized condition for cobalt-60 adsorption onto α-Fe2O3 NPs was obtained in pH 6.5, initial radiocation concentration of 1 mg/L, contact time of 2 h and nano-α-Fe2O3 sorbent concentration of 20 mg/L. On the other hand, the results indicated that adsorption of cobalt-60 onto the synthesized nano-α-Fe2O3 well fitted the Ho model as linear pseudo-second-order kinetics. In contrast, analysis of equilibrium data showed that the Redlich-Peterson isotherm model was suitable for describing cobalt-60 adsorption onto α-Fe2O3 NPs and the maximum uptake capacity was about 142.86 mg/g at 25 ± 1 °C according to Langmuir isotherm results. Meanwhile, the actual maximum adsorption capacity was about 99 mg/g. Therefore, it can be concluded that the synthesized novel surface-modified α-Fe2O3 NPs is an environment-friendly and a promising adsorbent for the removal of cobalt-60 radiocations from aqueous solutions. [ABSTRACT FROM AUTHOR]

Gamma radiation can be utilized as a mutagenic agent for inducing genetic variability in plant species. However, the adequate dose of radiation must be established before starting a mutagenesisbased breeding program. The objective was to determine the mean lethal dose (LD50) and the dose for the mean growth reduction (GR50) in Wilman lovegrass (Eragrostis superba Peyr.). For this purpose, the seeds were radiated with doses of 0 (control treatment), 100, 200, 300, 450, 600, 900, 1400, 2000 and 4000 Gray. The evaluated variables were germination percentage, germination speed index, plumule length, radicle length, forage yield, seed production, leaf-stem ratio and chlorophyll concentration index. The data were analyzed through regression analyses and the Dunnett's mean comparison test. The LD50 and GR50 generated for each of the evaluated variables were calculated with the resulting regression equation. Based on the values of LD50 and GR50, a weighted mean was estimated; the LD50 was weighted with 30 % while the GR50 with 10%. In general, all the evaluated characteristics were affected by the radiation treatment (P<0.05), and their behavior was adjusted to linear square models (P<0.05), allowing the determination of the LD50 and the GR50. The weighting average of both parameters, estimated at 2486 Gy, is recommended for the genetic breeding of Wilman lovegrass. The results of this study will allow implementing mutagenesis-based plant breeding programs in Wilman lovegrass. [ABSTRACT FROM AUTHOR]

Radiotherapy is the treatment of choice for non‐resectable canine thyroid carcinoma. High tumor response rates and median survival times of 2 years or longer have been previously reported with conventionally fractionated and hypofractionated protocols, even in dogs with distant metastasis. The objective of this retrospective, descriptive, case series study was to evaluate the clinical outcomes of dogs with thyroid carcinoma irradiated with palliative intent using hypofractionated radiotherapy at our institution. Medical records of 20 dogs treated between 1999 and 2014 were reviewed. All dogs had macroscopic primary tumors and presented with tumor‐related clinical signs. Median longest tumor diameter was 10 cm. Nineteen dogs (95%) had metastasis (7/19 lymph node; 16/19 distant metastasis). Most dogs were treated with four weekly fractions of 6.5–8 Gy. Radiotherapy was well tolerated in 17 dogs; three died of respiratory compromise before completing radiotherapy. Eleven dogs received adjuvant chemotherapy. Five dogs experienced a local tumor response including two complete and three partial responses. Overall median survival time was 170 days (range, 1–824 days; 95% CI: 58–392 days). Of potential variables examined (radiation delivery system and protocol, tumor size and location, vascular/lymphatic invasion, metastatic disease, chemotherapy, tumor response), only achievement of complete or partial response was predictive of overall survival. In contrast to previously reported cohorts, dogs with clinical signs and stage IV disease predominated in this study. Previous studies may over‐estimate survival following hypofractionated radiotherapy in dogs with advanced thyroid carcinoma. [ABSTRACT FROM AUTHOR]

Abstract A generalized methodology was developed for automating the detection of radioisotopes from gamma-ray spectra collected from an aircraft platform using sodium-iodide detectors. Employing data provided by the U.S Environmental Protection Agency Airborne Spectral Photometric Environmental Collection Technology (ASPECT) program, multivariate classification models based on nonparametric linear discriminant analysis were developed for application to spectra that were preprocessed through a combination of altitude-based scaling and digital filtering. Training sets of spectra for use in building classification models were assembled from a combination of background spectra collected in the field and synthesized spectra obtained by superimposing laboratory-collected spectra of target radioisotopes onto field backgrounds. This approach eliminated the need for field experimentation with radioactive sources for use in building classification models. Through a bi-Gaussian modeling procedure, the discriminant scores that served as the outputs from the classification models were related to associated confidence levels. This provided an easily interpreted result regarding the presence or absence of the signature of a specific radioisotope in each collected spectrum. Through the use of this approach, classifiers were built for cesium-137 (137Cs) and cobalt-60 (60Co), two radioisotopes that are of interest in airborne radiological monitoring applications. The optimized classifiers were tested with field data collected from a set of six geographically diverse sites, three of which contained either 137Cs, 60Co, or both. When the optimized classification models were applied, the overall percentages of correct classifications for spectra collected at these sites were 99.9 and 97.9% for the 60Co and 137Cs classifiers, respectively. Highlights • Automated detection of 137Cs and 60Co by airborne gamma-ray spectroscopy. • Supervised pattern recognition of digitally filtered gamma-ray spectra. • Methods development does not require field data of radioactive sources. • Detection decisions supplied with % confidence for ease of interpretation. • Methodology demonstrated with aerial surveys of six field sites. [ABSTRACT FROM AUTHOR]

Abstract With respect to the limitations use of methyl bromide and phosphine, employing ionizing radiation to control stored product pests has attracted great attention. The aim of this study is the investigation of the combined effects of gamma irradiation as viable alternatives to synthetic insecticides and environmental management on mortality and sterility of Rhyzopertha dominica (Fabricius) in a wheat cultivar (Gascogen). The effect of doses range from 30 to 2000 Gy gamma irradiation in combination with manipulation of temperature (15, 21, 27 and 32 °C) and relative humidity (20%, 50%, 65% and 85%) on 5–10 days old adults of R. dominica in Gascogen cultivar of wheat were explored. The experiments were repeated three times and conducted in The Nuclear Agriculture Research School in Karaj and laboratory of shahid steki silo in shahre-kord. Probit analysis revealed that both temperature and relative humidity had combined effects when used with gamma irradiation. The lowest doses of gamma ray required to kill 25% (14.2 Gy) and 50% (610.8 Gy) of the population (LD 25 and LD 50) were recorded at 21 °C and 85% relative humidity respectively. The low dose for 99% mortality (LD 99 ; 2386.7 Gy) was recorded for beetles maintained at 21 °C and 50% relative humidity. The effect of temperature (15, 21, 27 and 32 °C) on sterility caused by gamma irradiation was also investigated. The results showed that the F 1 generation emerged only when the beetles were treated with doses of 0–100 Gy at 32 °C and 0–70 Gy at 27 °C. These results indicate that temperature and relative humidity play an important role in the susceptibility of the lesser grain beetle to gamma irradiation. The results suggest that controlling the efficiency of gamma radiation through environmental control allows the use of low doses of gamma radiation that have a less harmful effect on human health, non-target organisms and seed agronomic features. Graphical abstract Unlabelled Image Highlights • The low doses of irradiation for 100% mortality were recorded in R. dominica maintained at 21 °C and 50% relative humidity. • The high dose of irradiation for 100% mortality was recorded in R. dominica maintained at 15 °C and 20% relative humidity. • Doses of gamma irradiation higher than 100 Gy cause 100% sterility in the population of R. dominica at 32 °C. [ABSTRACT FROM AUTHOR]

To fulfil the technical requirements for accreditation to ISO/IEC 17025, the end-to-end validation of all processes associated with standardising 60Co, including gravimetric source dispensing, primary standardisation by the 4π(LS)β-γ coincidence and live-timed anti-coincidence extrapolation techniques, and impurity determination were performed and documented. Pure-beta-emitting impurities in a 60Co stock solution were identified. The impact of such impurities on measurement by liquid scintillation counting and comparison in the ESIR are discussed. A fresh 60Co source was produced, standardised, and compared using the SIR. • Progress towards ISO/IEC 17025 accreditation. • Cobalt-60 produced by neutron activation of pure cobalt metal in OPAL reactor. • 4π(LS)β-γ live-timed anti-coincidence extrapolation technique validated. • Pure-beta impurities (14C and 99Tc) in 60Co solution identified and quantified. • Impact of pure beta impurities on ESIR demonstrated and discussed. [ABSTRACT FROM AUTHOR]