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Purpose: In this study, the human absorbed dose of 111In-DOTA-PR81 as a new radioimmunoconjugate for single-photon emission computed tomography (SPECT) imaging of MUC1 + breast cancer was determined. Materials and Methods: The complex was prepared at optimized conditions in about 1 h and 38°C. The radiochemical purity of the tracer was investigated using the instant thin-layer chromatography method method, showing purity of higher than 96%. After evaluating the stability of the product in human serum and room temperature, the biological distribution of the radiolabeled compound was studied in normal rats and tumor-bearing mice. Finally, the human absorbed dose of the complex was estimated based on animals' data using radiation dose assessment resource and Spark et al. methods. Results: High uptake of the complex in MUC1 + breast tumors compared to other nontarget organs shows that the radioimmunoconjugate is a beneficial agent for SPECT imaging of MUC1 + breast cancer. Human organs absorbed dose estimation of the complex demonstrated the highest amounts of the absorbed dose are in the liver and kidneys with 0.384 and 0.245 mGy/MBq, respectively. Conclusions: 111In-DOTA-PR81 radioimmunoconjugate is a high potential agent for MUC1 + breast cancer SPECT imaging and estimated absorbed dose values could helpfully use for the determination of the maximum injectable dose.

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OBJECTIVES: To compare image quality and radiation dose of computed tomography angiography (CTA) of the head and neck in patients using two Gemstone Spectral Imaging (GSI) scanning protocols. METHODS: A total of 100 patients who underwent head-neck CTA were divided into two groups (A and B) according to the scanning protocols, with 50 patients in each group. The patients in group A underwent GSI scanning protocol 1 (GSI profile: head and neck CTA), while those in group B underwent GSI scanning protocol 2 (GSI profile: chest 80 mm). All images were reconstructed using 40% and 70% pre- and post-adaptive level statistical iterative reconstruction V (pre-ASiR-V and post-ASiR-V) algorithms, respectively. The CT dose index (CTDIvol) and dose-length (DLP) product were recorded and the mean value was calculated and converted to the effective dose. CT values, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of all images were calculated. Additionally, subjective image evaluation was conducted by two independent radiologists using a five-point scoring method. All data were statistically analyzed. RESULTS: There were no significant differences in the CT values, SNR, CNR, and subjective score between groups A and B (p > 0.05); however, the mean effective dose (1.2±0.1 mSv) in group B was 45.5% lower than that in group A (2.2±0.2 mSv) (p < 0.05). CONCLUSIONS: GSI scanning protocol 2 could more effectively reduce the radiation dose in head-neck CT angiography while maintaining image quality compared to GSI scanning protocol 1.

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BACKGROUND: This article summarizes the methodology, results, and challenges of the reconstruction of red bone marrow and male breast doses for a 1982-person sub-cohort of ∼114,270 U.S. military veterans who participated in eight atmospheric nuclear weapons tests between 1945 and 1962. These doses are being used in an epidemiological investigation of leukemia and male breast cancer as part of a study of one million U.S. persons to investigate risk from chronic low-dose radiation exposure. METHODS: Previous doses to these veterans had been estimated for compensation and tended to be biased high but newly available documentation made calculating individual doses and uncertainties using detailed exposure scenarios for each veteran possible. The techniques outlined in this report detail the methodology for developing individual scenarios and accounting for bias and uncertainty in dose based on the assumptions made about exposure. RESULTS: Doses to the atomic veterans in this sub-cohort were relatively low, with about two-thirds receiving red bone marrow doses <5 mGy and only four individuals receiving a red bone marrow dose >50 mGy. The average red bone marrow dose for members of the sub-cohort was 5.9 mGy. Doses to male breast were approximately 20% higher than red bone marrow doses. DISCUSSION AND CHALLENGES: Relatively low uncertainty was achieved as a result of our methodology for reconstructing exposures based on knowledge of the individual veterans' locations and activities from military records. Challenges did arise from use of military records to determine probability of participation in specific activities but accounted for in estimates of uncertainty.

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Aims: Calculation of the absorbed dose in human organs is one of the first steps for developing new radiopharmaceuticals. The aim of this study is to estimate the human absorbed dose of a newly developed 68Ga-NODAGA-RGD-BBN radiolabeled compound. Materials and Methods: 68Ga-NODAGA-RGD-BBN was prepared by varying different parameters at optimized conditions. The stability of the radiolabeled peptide in phosphate-buffered saline (PBS) and in human serum was evaluated for 120 min. Afterward, the biodistribution of the complex was assessed in normal and tumor-bearing mice, at least for 120 min postinjection. Finally, the human absorbed dose of 68Ga-NODAGA-RGD-BBN was estimated based on mice data using Radiation Dose Assessment Resource and Spark method. Results: 68Ga-NODAGA-RGD-BBN was produced with radiochemical purity of more than 98% (high-performance liquid chromatography/ radio thin layer chromatography (RTLC)) with high stability in PBS buffer and in human serum at least for 2 h. The complex demonstrated high uptake in gastrin-releasing peptide receptor-expressing tumors compared to other nontarget organs. Furthermore, the dose assessment for the complex showed that the kidneys receive the highest absorbed dose in comparison with other organs. Conclusion: The result of this study showed that 68Ga-NODAGA-RGD-BBN is an effective and radiolabeled ligand for tumor detection, however more studies are still needed.

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Dose assessments were required for the epidemiological study of residents living near nuclear power plants. In the present work, environmental pathway models have been applied to estimate radiation doses to residents living near the nuclear power plants in Taiwan. Best estimates of doses were made for residents by their age groups in different compass sectors centered at the nuclear power plants. In each sector, radiation doses were assessed using the averaged environmental, consumption and lifestyle data. For epidemiological analyses of cancer risks in different organs or tissues, individual organ absorbed doses were assessed for both the airborne and waterborne effluent releases. Such assessments were performed based on the historic data, including measured effluent releases, detected meteorological parameters, and surveyed data on the production and consumption of local agricultural, fishery and livestock products, etc. Exposure pathways consisted of the external irradiations from air submersion, ground deposition and water immersion plus the internal irradiations from inhalation and ingestion. Age-dependent annual intakes and occupancy time were locally surveyed. Dose conversion coefficients were taken from published data after International Commission on Radiological Protection Publication 60. Annual doses and cumulated doses during residence were assessed and examined for their dependence on age, organ and compass sector.

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A radiological box model of the Aegean Sea has been developed simulating the dispersion and fate of radionuclides in the marine environment. The model incorporates all transfer processes within abiotic and biotic compartments in combination with appropriate site-specific information. The model was calibrated using empirical radiological data, with the simulation of 137Cs dispersion after the Chernobyl. Environmental sensitivity analysis has been carried out based on Chernobyl 137Cs fallout, in terms of doses to representative marine organisms (fish, crustacean and molluscs) and human population. Comparison of the results with doses from natural sources and sensitivity estimations for shallow marine environments has been performed in order to reveal the vulnerability of each sub-region. The main characteristics and parameters controlling the radioecological processes are also discussed.

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The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the body including the hands and fingers; to suggest recommendations for individual monitoring; and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, Hp(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, Hp(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess Hp(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36-39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; Hp(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information.

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Concentrations of radon (222Rn) and thoron (220Rn) were measured in the air of different marble factories by using a nuclear track technique. The influence of the marble dust nature and ventilation on radon and thoron concentrations was investigated. It was observed that measured radon and thoron concentration ranged from 310 to 903 Bq m-3 and 6 to 48 Bq m-3, respectively. In addition, alpha-activities due to the unattached and attached fractions of 218Po and 214Po radon short-lived progeny were evaluated in the marble factories studied. Committed equivalent doses due to the attached and unattached fractions of 218Po and 214Po nuclei were evaluated in the lung tissues of marble factory workers. The dependence of the resulting committed equivalent dose on the concentration of the attached and unattached fractions of the 218Po and 214Po radionuclides and mass of the tissue was investigated. The resulting annual committed effective doses to the lung of marble factory workers due to the attached and unattached fractions of the 218Po and 214Po radionuclides were calculated. The obtained results show that about 80% of the global committed effective doses received by workers in the studied marble factories are due to the attached fraction of the 218Po and 214Po radon short-lived daughters from the inhalation of polluted air. Male workers spending 8 h per day (2080 h per year) in a marble factory receive a maximum dose of 34.46 mSv y-1 which is higher than the (3-10 mSv y-1) dose limit interval given by the ICRP. Good agreement was found between data obtained for the average effective dose gotten by using this method and the UNSCEAR and ICRP conversion dose coefficients.

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Dicentric chromosome assay (DCA) is most frequently used for estimating the absorbed radiation dose in the peripheral blood lymphocytes of humans after occupational or incidental radiation exposure. DCA is considered to be the "gold standard" for estimating the absorbed radiation dose because the dicentric chromosome formation is fairly specific to ionizing radiation exposure and its baseline frequency is extremely low in non-exposed humans. However, performance of DCA for biodosimetry is labor intensive and time-consuming making its application impractical for radiological/nuclear mass casualty incidents. Realizing the critical need for rapid dose estimation particularly after radiological/nuclear disaster events, several laboratories have initiated efforts to automate some of the procedural steps involved in DCA. Although metaphase image capture and dicentric chromosome analysis have been automated using commercially available platforms, lack or an insufficient number of these platforms may pose a serious bottleneck when hundreds and thousands of samples need to be analyzed for rapid dose estimation. To circumvent this problem, a web-based approach for telescoring was initiated by our laboratory, which enabled the cytogeneticists around the globe to analyze and score digital images. To further increase the surge capacity of dicentric scorers, we recently initiated a dicentric training and scoring exercise involving a total of 50 volunteers at all academic levels without any prerequisite for experience in radiation cytogenetics. Out of the 50 volunteers enrolled thus far, only one outlier was found who overestimated the absorbed radiation dose. Our approach of training the civilians in dicentric chromosome analysis holds great promise for increasing the surge capacity of dicentric chromosome scorers for a rapid biodosimetry in the case of mass casualty scenarios.

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The activity concentration of natural and anthropogenic radionuclides was determined in different vegetable samples, and foods derived from animal origin, from different locations in the four cities of Southern Tunisia, where large-scale phosphate industries are operating. The aim of the studies was to establish a baseline database on radionuclide concentration in food materials and to evaluate the radiation dose to the general population due to its ingestion through the food chain. The activity concentrations of 40K, 210Pb, 226Ra, 228Ra and 137Cs was determined by gamma spectrometry using a HPGe detector, and from the measured activity concentrations, the doses were estimated using the dose coefficients given by the ICRP. The dose due to intake of radionuclides through mineral water was also determined. The total annual effective doses were found to be 2.2, 1.4, and 0.7 mSv y-1 for 1 y, 5-15 y and adult (>17 y) age groups, respectively. Among the radionuclides studied, 210Po was the highest contributor to the total dose, followed by 210Pb.

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Dicentric chromosome assay (DCA) is routinely used for estimating the absorbed radiation dose in exposed humans. Optimal lymphocyte viability is crucial for reliable dose estimation and most cytogenetic laboratories prefer the receipt of blood samples within 24 to 36 hours after collection. Delays in the shipment/receipt of samples can occur sometimes under certain unforeseen circumstances: (1) Adverse weather conditions, (2) distant location of blood collection sites, and (3) shipping and handling of a large number of samples after radiological/nuclear mass casualty incident(s). To circumvent some of these limitations, we evaluated the suitability of ex vivo irradiated blood samples stored in the presence of phytohemagglutinin (PHA) for 7 days at ambient temperature (22-24°C) for radiation biodosimetry. Blood samples stored in the presence of PHA for up to 7 days showed a higher mitotic index than blood samples stored without PHA. To verify the use of stored blood samples for DCA, frequencies of X-rays induced dicentric chromosomes were analyzed in the blood samples that were cultured either 24 hours after exposure or 7 days later after storage. Our results indicate that storage of ex vivo irradiated blood samples in the presence of PHA at ambient temperature was found optimal for DCA and that the radiation doses estimated by dicentric chromosome frequencies were grossly similar between the fresh and stored blood samples. Our study suggests that reliable and accurate biodosimetry results can be obtained for triage using blood samples stored for up to a week at ambient temperature in the presence of PHA.

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To establish a complete technical solution for the automatic radiation biological dose estimation platform for biological dose estimation and classification of the wounded in large-scale radiation accidents, the "dose-effect curve by dicentric chromosome (DIC) automatic analysis" was established and its accuracy was verified. The effects of analyzed cell number and the special treatment of the culture on dose estimation by DIC automatic analysis were studied. Besides, sample processing capabilities of the special equipments were tested. The fitted "dose-effect curve by DIC automatic analysis" was presented as follows: Y = (0.01806 ± 0.00032) D 2 + (0.01279 ± 0.00084) D + (0.0004891 ± 0.0001358) (R 2 = 0.961). Three-gradient scanning method, culture refrigeration method, and interprofessional collaboration under extreme conditions were proposed to improve the detection speed, prolong the sample processing time window, and reduce the equipment investment. In addition, the optimized device allocation ratio for the automatic biological dose estimation laboratory was proposed to eliminate the efficiency bottleneck. The complete set of technical solutions for the high-throughput automatic biological dose estimation laboratory proposed in this study can meet the requirements of early classification and rapid biological dose assessment of the wounded during the large-scale nuclear radiation events, and it is worthy of further promotion.

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Mass casualty scenarios of radiation exposure require high throughput biological dosimetry techniques for population triage in order to rapidly identify individuals who require clinical treatment. The manual dicentric assay is a highly suitable technique, but it is also very time consuming and requires well trained scorers. In the framework of the MULTIBIODOSE EU FP7 project, semi-automated dicentric scoring has been established in six European biodosimetry laboratories. Whole blood was irradiated with a Co-60 gamma source resulting in 8 different doses between 0 and 4.5Gy and then shipped to the six participating laboratories. To investigate two different scoring strategies, cell cultures were set up with short term (2-3h) or long term (24h) colcemid treatment. Three classifiers for automatic dicentric detection were applied, two of which were developed specifically for these two different culture techniques. The automation procedure included metaphase finding, capture of cells at high resolution and detection of dicentric candidates. The automatically detected dicentric candidates were then evaluated by a trained human scorer, which led to the term 'semi-automated' being applied to the analysis. The six participating laboratories established at least one semi-automated calibration curve each, using the appropriate classifier for their colcemid treatment time. There was no significant difference between the calibration curves established, regardless of the classifier used. The ratio of false positive to true positive dicentric candidates was dose dependent. The total staff effort required for analysing 150 metaphases using the semi-automated approach was 2 min as opposed to 60 min for manual scoring of 50 metaphases. Semi-automated dicentric scoring is a useful tool in a large scale radiation accident as it enables high throughput screening of samples for fast triage of potentially exposed individuals. Furthermore, the results from the participating laboratories were comparable which supports networking between laboratories for this assay.

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