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Abstract Background and purpose Rare but severe toxicities of the optic apparatus have been observed after treatment of intracranial tumours with proton therapy. Some adverse events have occurred at unusually low dose levels and are thus difficult to understand considering dose metrics only. When transitioning from double scattering to pencil beam scanning, little consideration was given to increased dose rates observed with the latter delivery paradigm. We explored if dose rate related metrics could provide additional predicting factors for the development of late visual toxicities. Materials and methods Radiation-induced intracranial visual pathway lesions were delineated on MRI for all index cases. Voxel-wise maximum dose rate (MDR) was calculated for 2 patients with observed optic nerve toxicities (CTCAE grade 3 and 4), and 6 similar control cases. Additionally, linear energy transfer (LET) related dose enhancing metrics were investigated. Results For the index cases, which developed toxicities at low dose levels (mean, 50 GyRBE), some dose was delivered at higher instantaneous dose rates. While optic structures of non-toxicity cases were exposed to dose rates of up to 1 to 3.2 GyRBE/s, the pre-chiasmatic optic nerves of the 2 toxicity cases were exposed to dose rates above 3.7 GyRBE/s. LET-related metrics were not substantially different between the index and non-toxicity cases. Conclusions Our observations reveal large variations in instantaneous dose rates experienced by different volumes within our patient cohort, even when considering the same indications and beam arrangement. High dose rate regions are spatially overlapping with the radiation induced toxicity areas in the follow up images. At this point, it is not feasible to establish causality between exposure to high dose rates and the development of late optic apparatus toxicities due to the low incidence of injury.

Natural background gamma rays and their effects on human health are essential components of both radiation protection and public concern. In the frame of these aspects, the mapping of the natural gamma dose rate values of the Province of Asti is given. The Asti Fire Brigade Command approved a project relating to the mapping of gamma radiation from the natural background in the territory of Asti. The project engaged both the Nuclear, Biological, Chemical, and Radiological (NBCR) and Topography Applied to Rescue (TAS) components of the Asti Command. Skilled personnel, comprising level 1 TAS operators for data collection and level 2 TAS operators for cartographic analysis, were deployed across the six working days. The methodology involved the use of two digital handheld radiation G-M detectors, in conjunction with a portable GPS unit, including the Global Mapper software. One of the significant findings of this study is the observation that the natural gamma dose rate levels were 201.25% higher in the streets of the city center compared to other areas, predominantly because the building materials in these locations contain a higher amount of natural radionuclides. The results indicated that the level of natural gamma dose rates in the studied region is close to the global average value.

Objective(s): In systemic radionuclide therapy such as radioiodine (I-131) for differentiated thyroid cancer, post-therapy dosimetry is essential to verify pre-therapy predictions, which in turn informs the next treatment. However, post-therapy multi-time point dosimetry is resource intensive and unfeasible in many institutions. We devised a schema of rapid predictive dosimetry by circumventing post-First Strike multi-time point dosimetry with carefully assigned gestalt values of predicted kinetics to personalise the Second Strike prescription.Methods: Verification is performed after the First Strike. Patient-specific time-activity curve is plotted from serial measurements of whole body exposure rates to obtain its decay constant; its inverse is the whole body Time Integrated Activity Coefficient (TIAC). The percentage of whole body TIAC attributed to blood is carefully assigned by gestalt based on population kinetics tabulated in Part 1, adjusted by any metastasis on I-131 whole body scintigraphy. Marrow absorbed dose is calculated by EANM formularism. Lung safety threshold at 48h post-therapy is linearly scaled by height, where the patient’s risk of lung radiotoxicity is revealed from the whole body time-activity curve value at 48h. Predictive prescription for the second I-131 fraction (Second Strike) is by careful gestalt assessment based on predicted kinetics, remaining marrow and lung tolerance, marrow dose rate constraint per fraction (0.265 Gy/h), local regulatory and facility requirements in relation to radiation protection. Tumour dosimetry is obviated under the assumption of severe tumour absorbed dose heterogeneity. The final prescription for the Second Strike is usually the lowest I-131 activity amongst all clinical, dosimetric and regulatory constraints.Results: This schema is incorporated into a Predictive Calculator spreadsheet for rapid predictive dosimetry, and is freely available. Calculations may be completed within minutes to generate personalised predictive prescriptions, making it feasible for routine clinical implementation.Conclusion: Our innovative schema of rapid verification and predictive dosimetry bridges the technological gap between empiric vs theranostic prescription to help institutions modernise. Its expeditious design makes this schema feasible to be integrated into the routine clinical workflow. Its predictive estimates provide invaluable dosimetric insight to inform the next I-131 fraction, allowing every prescription to be scientifically rationalised and personalised according to individual circumstances.

The Sentinel Lymph Node (SLN) or Sentinel Lymph Node Biopsy (SLNB) technique involves various professionals from different departments in clinical settings to manage breast cancer patients properly. Tracing the nodular involvement of breast cancer patients requires radiation source Tc99m labeled with colloidal albumin to be injected at the tumor site. The patient becomes a radiation source for a sufficient time, which concerns the Nuclear Medicine (NM) and surgical staff. The study aims to provide the radiation doses of staff in the NM department during the SLN scintigraphy procedure and obtain an empirical model for calculating the radiation doses to staff in the surgical department from that particular patient. Radiation doses in SLN technique for breast cancer patients are minimal, and a sufficient number of SLN biopsy procedures can be performed by hospital staff within the category of non-radiation workers.

Neutron induced damage in future nuclear materials can be studied using heavy ion beams only if the differences in the microstructure evolution are well understood. Large variations in the damage dose rate, caused by scanning of the ion beam, can alter the microstructure compared to steady-state irradiation. We study the effect of scanning on the microstructure by irradiating pure iron with a 10 MeV Fe ion beam to a dose of 0.2 dpa. The beam is scanned in one direction with frequencies of 200 Hz and 10 kHz. Different shapes of the beam are also used to study the effect of dose variation. All of the irradiations are conducted at room temperature using the DiFU chamber at RBI. TEM analysis shows differences between the narrow beam and defocused irradiation modes, including unusual void formation observed at 10 kHz. A wider beam reduces the effect of scanning speed and no voids are found in this scanning case.

The output constancy of the accelerator used for boron neutron capture therapy (BNCT) is essential to ensuring anti-tumor efficacy and safety. BNCT as currently practiced requires a wide variety of beam quality assessments to ensure that RBE dose errors are maintained within 5%. However, the necessity of maintaining a constant beam dose rate has not been fully discussed. We therefore clarified the effect of different physical dose rates of the accelerator BNCT on biological effects. SAS and A172 cells exposed to 10B-boronophenylalanine were irradiated using a neutron beam (normal operating current, 100 μA) at the Aomori Quantum Science Center. Thermal neutron flux was attenuated to 50.0 ± 0.96% under 50 μA irradiation compared to that under 100 μA irradiation. Cells were given physical doses of 1.67 and 3.36 Gy at 30 and 60 mC, respectively, and survival was significantly increased after 50 μA irradiation for both cell types (p = 0.0052 for SAS; p = 0.046 for A172, for 60 mC). Differences in accelerator BNCT beam dose rates have non-negligible effects on biological effects. Dose rate fluctuations and differences should not be easily permitted to obtain consistent biological effects.

To establish the high-pressure ionization chamber products for dose rate monitoring of the environmental level γ ray, the design from the aspects of ionization chamber shell, detector, electronic system, etc. are optimized, to improve the environmental adaptability, electromagnetic compatibility and reliability of the equipment. According to the standard method, the general quality characteristics test was carried out at a third party. The test results showed that the working and storage temperature range of the product was -10 ℃-45 ℃; Humidity range ≤93% RH; It has certain anti-vibration and impact capacity, and meets the requirements of the severity level 2M1 of transport environmental conditions in GB/T 8993—1998; Electrostatic discharge immunity and radio frequency electromagnetic field radiation immunity in electromagnetic compatibility shall meet the relevant requirements of GB/T 17626-2—2018 and GB/T 17626-3—2016; The reliability meets the requirement of MTBF≥1 000 h. The environmental adaptability, electromagnetic compatibility and reliability of this product meet the requirements of meter-level products. It can be used as a portable radiation dosimeter in climatefree places. High pressure ionization chamber can be used as a high accuracy work measuring instrument for ambient level air kerma to carry out radiation dose monitoring.

With the development of radiomedical technology, medical cyclotron proton accelerators have broad market prospects in China. China’s construction of medical cyclotron proton accelerator test room can improve the production efficiency of imported medical cyclotron proton accelerator. In order to ensure the radiation safety of the test room, this paper selects the 16 MeV cyclotron accelerator test room with a large proportion of imports as the research object, using FLUKA software to establish the target, shield and material model, setting the particle type, energy, beam intensity, beam loss rate and other parameters, and simulateing the radiation dose field distribution around the test room. The results show that the dose rate range of 30 cm outside the test room is 0.146~1.801 μSv/h, which meets the dose rate limit of 25 μSv/h. The research methods and results of this paper can provide reference for the radiation safety analysis of similar engineering.

Abstract Background Acrylamide poisoning is often reported as chronic poisoning presenting with peripheral neuropathy or carcinogenic action due to long-term exposure to low concentrations. However, there have been few reports of acute poisoning due to oral ingestion of acrylamide, where the symptoms appear a few hours after ingestion. Here, we report a case of acute acrylamide poisoning where a high concentration was ingested in a short time, resulting in a fatal outcome due to the rapid course of events. Case presentation The patient was an adolescent female who ingested 150 ml (148 g) of acrylamide with suicidal intent. A disorder of consciousness was observed when the emergency medical team arrived 36 min later. An hour later, tracheal intubation and intravenous access were performed at a hospital, and 2 h after that, she was transported to our hospital. After she arrived at the hospital, circulatory dynamics could not be maintained despite vasopressor and colloid osmotic infusion, and hemodialysis could not be introduced. Subsequently, cardiopulmonary arrest occurred, and the patient passed away 7 h after ingestion. In the present case, severe symptoms appeared shortly after acrylamide ingestion, unlike other reported cases. In previous report summarizing animal studies, there was a relationship among the symptoms of acute poisoning, the dose, and onset time. The data from this case were compared to those from previous reports, and we were able to predict the early appearance of severe symptoms based on this comparison. Conclusion The severity of acute acrylamide poisoning by oral ingestion was primarily dependent on the amount and rate of ingestion.

Objective(s): The traditional practice of empiric radioiodine (I-131) prescription is scientifically obsolete and inappropriate for inoperable metastatic differentiated thyroid cancer. However, theranostically guided prescription is still years away for many institutions. A personalized predictive method of radioiodine prescription that bridges the gap between empiric and theranostic methods is presented. It is an adaptation of the “maximum tolerated activity” method, where serial blood sampling is replaced by population kinetics carefully chosen by the user. It aims to maximize crossfire benefits within safety constraints to overcome tumour absorbed dose heterogeneity for a safe and effective first radioiodine fraction i.e., the First Strike.Methods: The EANM method of blood dosimetry was incorporated with population kinetics, marrow and lung safety constraints, body habitus and clinical assessment of metastatic extent. Population data of whole body and blood kinetics in patients with and without metastases, prepared by recombinant human thyroid stimulating hormone or thyroid hormone withdrawal, and the maximum safe marrow dose rate were deduced from published data. For diffuse lung metastases, the lung safety limit was linearly scaled by height and separated into lung and remainder-of-body components.Results: The slowest whole body Time Integrated Activity Coefficient (TIAC) amongst patients with any metastases was 33.5±17.0 h and the highest percentage of whole body TIAC attributed to blood was 16.6±7.9%, prepared by thyroid hormone withdrawal. A variety of other average radioiodine kinetics is tabulated. Maximum safe marrow dose rate was deduced to be 0.265 Gy/h per fraction, where blood TIAC is normalised to administered activity. An easy-to-use calculator was developed which only requires height, weight and gender to populate recommendations for personalized First Strike prescription. The user decides by clinical gestalt whether the prescription is to be constrained by marrow or lung, then selects an activity depending on how extensive the metastases are likely to be. A Standard Female with oligometastasis and good urine output without diffuse lung metastasis is expected to safely tolerate 8.03 GBq of radioiodine as the First Strike.Conclusion: This predictive method will help institutions rationalise the First Strike prescription based on radiobiologically sound principles, personalised to individual circumstances.

Background and Aim: We measured radiation emission from the patients undergoing myocardial perfusion scan after leaving nuclear medicine department to demonstrate how much radiation hospital staff or patients’ companions, in the vicinity of the patients would receive. We also evaluated the relationship of age, sex, and body mass index with the emitted radiation rate. Material and Methods: In this study 60 patients (41 females and 19 males) after undergoing 99mTc-sestamibi myocardial perfusion scan with a dose of 925±185 MBq, were selected randomly. The equivalent dose rate at distances of 0.25 m, 1 m and 2 m from the patients were measured by a survey meter before leaving nuclear medicine department and after 12 & 24 hours. Data were analyzed by T-test, Pearson correlation coefficient and ANOVA. Results: The mean equivalent dose rates in unit of microsievert per hour at distances of 0.25 m, 1 m and 2 m from the patients were (120.6 ± 24.1, 19.4 ± 3.8, 8.4 ± 1.3) at leaving time, (29.1 ± 8.7, 5.3 ± 1.2, 2.1 ± 0.8) after 12 hours and (4.3 ± 1.5, 0.8 ± 0.6, 0.3 ± 0.1) after 24 hours, respectively. The mean equivalent dose rate showed no relationship with gender and age, but it was inversely correlated with body mass index (P-value

Abstract Background F-18 FDG (fluorodeoxyglucose) PET/CT procedures are one of the most growing studies used for patient management in oncology, cardiology, neurology, and other indications, in which the challenges meet both patients and clinicians, especially when we are looking for the presence/absence of disease progression and cure. This study was conducted to assess the external radiation dose after 18FDG-PET/CT examination. In total, 117 patients were enrolled in the study. Radiation exposure was measured using a calibrated RadEye SPRD-ER personal radiation detector. The measurements were taken at 0, 30, 100, 150, and 200 cm distance from the patient. The time of measurement was immediately post-injection, 30 min, 60 min after injection, and at the time of releasing the patient. Results The result showed that the mean radiation equivalent dose rate at 0 min/0 cm was 414 µSv/h, at 30 min/30 cm was 99.7 µSv/h, and 60 min/100 cm was 18.3 µSv/h. The radiation doses at different distances (0, 30, 100, 150, and 200 cm) were 160.9 µSv/h, 70.9 µSv/h, 12.4 µSv/h, 7 µSv/h, and 3.7 µSv/h, respectively. Conclusion In conclusion, the patient can be safely released after 2 h of injection in (18F-FDG) PET/CT and the radiation dose can be limited by increasing distance from the radiation source and also instructing them to drink much more water to enhance the process of excretions. The dose rates are low in this study; if the staff interact with multiple patients, they will not approach exposure limits. Similarly, dose rates are so low at patient release that family will not receive doses above regulatory limits.

Radiotherapy (RT) is performed in approximately 75% of patients with cancer, and its efficacy is often hampered by the low tolerance of the surrounding normal tissues. Recent advancements have demonstrated the potential to widen the therapeutic window using “very short” radiation treatment delivery (from a conventional dose rate between 0.5 Gy/min and 2 Gy/min to more than 40 Gy/s) causing a significant increase of normal tissue tolerance without varying the tumor effect. This phenomenon is called “FLASH Effect (FE)” and has been discovered by using electrons. Although several physical, dosimetric, and radiobiological aspects need to be clarified, current preclinical “in vivo” studies have reported a significant protective effect of FLASH RT on neurocognitive function, skin toxicity, lung fibrosis, and bowel injury. Therefore, the current radiobiological premises lay the foundation for groundbreaking potentials in clinical translation, which could be addressed to an initial application of Low Energy Electron FLASH (LEE) for the treatment of superficial tumors to a subsequent Very High Energy Electron FLASH (VHEE) for the treatment of deep tumors. Herein, we report a clinical investigational scenario that, if supported by preclinical studies, could be drawn in the near future.

Total ionizing dose (TID) effects of gamma rays were investigated on DDR4 dynamic random access memory (DRAM) and analyzed using TCAD simulations. In this study, we considered the operating states, dose rates, temperatures, and annealing to analyze the impact of TID under different conditions. The worst degradation was observed in the operated state and at a low-dose rate because of the absence of an electrostatic barrier that reduced the possibility of interface trap formation under unbiased and high-dose rate conditions. At lower temperatures, the effects of radiation were mitigated by the reduced production of protons ( $\text{H}^{+}$ ). In addition, the unbiased DRAM and high-temperature conditions are the fastest to recover during post-irradiation annealing. In TCAD simulations, the retention time decreased with increasing temperature because the band-to-band tunneling (BTBT) generation increased. Furthermore, the retention time and row activation latency ( $t_{\mathrm {RCD}}$ ) degraded as the concentration of the interface traps increased. This is because the interface traps caused leakage currents and hindered the flow of electrons.

NaI spectrometer is commonly used in nuclear emergency monitoring to realize dose rate monitoring and γ radionuclide identification. This paper introduces the calibration of the direct conversion of energy spectrum to dose for a 3″×3″ NaI spectrometer by using the G(E) function method. The standard energy spectrum data under different energies are obtained by using 152Eu, 133Ba, 241Am, 137Cs, 60Co and other standard point sources, and the energy spectrum data under other energies are simulated and calculated by Geant4 program, and the conversion of energy spectrum information to air absorption dose rate is realized. The analysis results show that in a certain dose rate range, the G(E) function method can be used to convert the energy spectrum information to dose rate, and the results are acceptable and meet the requirements of emergency monitoring.

Background: The inclusive symptom of breast cancer is a new mass or lump. Breast tumors may be a participation of dissimilar types or combination of invasive and in situ cancer. The positron emitting radionuclides may be employed to treat the breast. Methods: The various configurations of breast may be optimized to decrease the absorbed radiation dose, since the average glandular dose is regularly utilized as a criterion in radiation-risk detection. In this study, two configurations in cubic-rectangular (CR) and cylindrical-conical (CC) sketches along with appropriate assumptions were modelled and simulated via Monte Carlo technique, and the acquired dose rate (DR) values were compared. Results: The amounts of scattering and absorption cross sections of radiations next to the DR value reduced as the height of the CR sketch decreases. The mean dose rate value in the CR sketch reduced by 96.83% compared to that in the CC sketch. Additionally, raising the distance from the nipple (or raising the depth) reduced the DR values for both configurations. While the source of positron emitter was close to the right breast, the relative difference of the DR values between two sketches had major influence, for the CR outline which was high at the lower depths, and decreased linearly by increasing the depth. The accumulated DR value reduced severely in the CR sketch rather than the CC one. Conclusion: This study may be helpful to inspect deformed breast tissue in treatment planning.

Recent discovery and investigation of the flow of glasses under the electron beams of transmission electron microscopes raised the question of eventual occurrence of such type effects in the vitrified highly radioactive nuclear waste (HLW). In connection to this, we analyse here the flow of glasses and glass–liquid transition in conditions of continuous electron irradiation such as under the e-beam of transmission electron microscopes (TEM) utilising the configuron (broken chemical bond) concept and configuron percolation theory (CPT) methods. It is shown that in such conditions, the fluidity of glasses always increases with a substantial decrease in activation energy of flow at low temperatures and that the main parameter that controls this behaviour is the dose rate of absorbed radiation in the glass. It is revealed that at high dose rates, the temperature of glass–liquid transition sharply drops, and the glass is fully fluidised. Numerical estimations show that the dose rates of TEM e-beams where the silicate glasses were fluidised are many orders of magnitude higher compared to the dose rates characteristic for currently vitrified HLW.

Operational dosimetry solves the problem of implementing the principle of optimizing radiation safety, which is closely related to regulation and justification and implies a realistic achievable reduction in the dose load on a person when using ionizing radiation sources by reducing operating time, increasing the distance to radioactive material and shielding for attenuation of ionization flux. The article describes two ways of determining the thickness of shielding under necessity of making operational decision to protect a person from radionuclide source of known activity or the dose rate created by it. Based on the required multiplicity of its attenuation, which allows determining the number of half attenuation layers in the shield or its thickness, is also dependent on the energy of radiation, emitted by the source.

The TID (total ionizing dose) in-situ experiments of LC1020B, an anti-fuse FPGA (Field Programmable Gate Array) device, were designed and carried out under different dose rates, and the influence of dose rate on the TID effect of FPGA was studied. The experimental results show that: 1) the TID irradiation failure of the FPGA under different dose rates has nothing to do with the input voltage parameter exceeding the standard. 2) with the decrease of cobalt source irradiation dose rate [171, 26.83, and 2.68 mGy(Si)/s], the TID effect failure dose threshold [168, 229, and 334 Gy(Si), respectively] of the FPGA gradually increased, showing obvious attenuation of low dose rate damage. Theoretical analysis suggests that, compared with the space charge limitation effect, the oxide charge annealing effect plays a dominant role, and longer irradiation time is beneficial to the oxide charge annealing. And based on the experimental data, an FPGA TID analytical model with power consumption current as the damage characterization parameter is established, which lays a foundation for scientific evaluation of radiation effect of anti-fuse FPGAs.

The foreign materials in primary of nuclear power plant are activated with the coolant into the core, and the activated foreign materials are highly radioactive, while these highly radioactive foreign materials are often easily deposited in the primary related equipment. Hence, operators are frequently overexposed to radiation during foreign body salvage work in primary systems. Special transfer shielding devices, high discharge waste storage containers, and transfer area isolation control are designed to effectively reduce the impact of foreign body transfer and storage on the radiation level of the surrounding area and to ensure the radiation safety of the staff. Theoretical calculations of foreign body activation are consistent with the measured on-site radiation levels and can be used to guide the radiation protection work plan and personnel protection measures during foreign body salvage work.

In this paper, a new collimator based on Hygeia GMX-1 cobalt (60Co) radiosurgery system was designed and analyzed using the Monte Carlo simulation program GEANT4. The results of EBT3 film measurements showed that the field penumbra of the improved collimator was reduced by 17.6% and the absorbed dose rate was 2.12 times higher, while the source activity, source axis distance and field size remained unchanged. The collimator has significant advantages in the two key technical parameters of absorbed dose rate and penumbra.

Scintillation detectors, which are widely used in environmental field study for measurement of radiation dose, are devices that experience wide range of temperature changes when in use. One of the characteristic of scintillation detectors are that, they are very sensitive to change in temperature and hence, every scintillation detector have temperature stabilization inside them. The temperature-dependence coefficient which is part of the detector calculation is the simplest stabilization method that is used. In this work, the BDKG-03 scintillation detector which is used to measure gamma radiation was operated under a controlled condition using a climatic chamber. The BDKG-03 scintillation detector has a temperature stabilizing built-in algorithm. The dose rate and count rate of the gamma background radiation for different temperatures ranging from -40 – +40 °C in increment of 10 °C were measured and studied. The main aim of this work was to study the effect of different ranges of temperature for subsequent calculation of temperature correction coefficient. An analytical result from the experimental result shows that dose rate measurement using the built-in algorithm gives a precise reading as temperature increases. The temperature correction coefficient was found based on dependence.

The article provides a description of steps which were made to make comparison between numerically simulated and measured dose rates in Izotop gamma-irradiation facility (Budapest, Hungary) Numerical simulation was carried out with the help of software toolkit GEANT4. Dose measurement were made by ethanol-chlorobenzene (ECB) dosimeters. The comparison shows a good agreement between simulated and measured values. Worst accuracy was 17.08%.

Introduction: The present study investigatedthe risks of ionizing radiation on sperm counts in chronic doses and compared the findings with previous results in similar and different conditions to minimize oxidant stress on sperm parameters rather than using black seed oil. Material and Methods: Twenty rats were used in experimental designs 1 and allocated unordered to four groups. Each group included five. The ranges of 2-3 months and 170 -200 g, respectively .The healthy rats were obtained from the University of Mosul ,Iraq .Experimental design 2, was conducted on 50 rats .The rats were exposed to three different doses for 30 days similar to those of experimental design 1. Oral black seed oil was administrated a dose of 20 mg/kg in group 2 . Results: In experimental design 1, there was a significant decrease in sperm count, live sperm percentage and normal sperm percentages respectively. However a significant increase was observed in dead sperm and abnormal sperm percentages in experimental design 1.The administration of black seed oil in excremental design 2 improved all the parameters with reducing abnormal and dead sperm counts rather than increasing normal and live sperm counts at all doses . Conclusion: The use of black seed reduce the oxidative stress caused by low dose gamma radiation .Therefore , this substance can be used as a therapeutic option for the treatment of several type of cancer especially those under the treatment of low dose gamma radiation through enhancement of protection for a long time.

The pressurized heavy-water reactors (PHWR) consist of a low-pressure horizontal reactor vessel, calandria, containing heavy water as moderator. The calandria is pierced by a large number of coolant tubes (also called pressure tubes [PTs], 392 in 540 MWe PHWR), which contains fuel bundles, and through which pressurized heavy-water coolant circulates. During biennial shut down in 2017, in-service inspection of coolant channels in Tarapur atomic power station-4 (TAPS-4) had been carried out and after the review of results of inspection, it was recommended by various groups of experts that channel L-08 should be removed for postirradiation examination at Bhabha Atomic Research Center (BARC). Before the channel removal job, one special shielding flask was designed to shift the removed channel to BARC. The integrity test of special shielding flask was carried out by safely placing cobalt-60 (source strength 851000 MBq) capsule source inside the shielding flask with the help of cranking unit mechanism followed by dose rate mapping on the outer surface of the flask. To establish the hydrogen pickup rates in L-08 PT, sliver samples were collected and separately sent to BARC. Four metallic sliver samples were obtained at four different distances from north E-face. The activity content present in each sliver sample was also estimated. The maximum activity estimated was 2313.24 MBq. Subsequently, L-08 coolant channel was cut from both sides using a chipless tool. Jobs involving heavy water (D2O) collection work were carried out with a ventilated plastic suit. Derived air concentration (DAC) of tritium at the work location was maintained below 1DAC during the entire activity. Particulate DAC was found below the detectable limit. Floor contamination checks and floor decontamination were conducted at regular intervals to avoid buildup of contamination. As a result of such high-quality radiological safety measures, only 25 workers, out of 270 radiation workers, have received a cumulative dose of more than 3 mSv in direct reading dosimeter with a maximum individual dose of 8.45 mSv and maximum individual uptake of 0.39 GBq/m3. Job was completed with a total collective dose of 324.35P-mSv which is 14.5% lower than estimated. This article highlights some of the critical tasks involved in the cutting and the removal of irradiated coolant channel from the core of 540 Mwe TAPS-4 reactor which is a first of kind activity in nature.

(1) Background: cystamine and its reduced form cysteamine have radioprotective/antioxidant effects in vivo. In this study, we use an in vitro model system to examine the behavior of cystamine towards the reactive primary species produced during the radiolysis of the Fricke dosimeter under high dose-rate irradiation conditions. (2) Methods: our approach was to use the familiar radiolytic oxidation of ferrous to ferric ions as an indicator of the radioprotective/antioxidant capacity of cystamine. A Monte Carlo computer code was used to simulate the multi-track radiation-induced chemistry of aerated and deaerated Fricke-cystamine solutions as a function of dose rate while covering a large range of cystamine concentrations. (3) Results: our simulations revealed that cystamine provides better protection at pulsed dose rates compared to conventional, low-dose-rate irradiations. Furthermore, our simulations confirmed the radical-capturing ability of cystamine, clearly indicating the strong antioxidant profile of this compound. (4) Conclusion: assuming that these findings can be transposable to cells and tissues at physiological pH, it is suggested that combining cystamine with FLASH-RT could be a promising approach to further enhance the therapeutic ratio of cancer cure.

PurposeThis work aims to study the dose and ultra-high-dose rate characteristics of transmission proton pencil beam scanning (PBS) FLASH radiotherapy (RT) for hypofractionation liver cancer based on the parameters of a commercially available proton system operating under FLASH mode.Methods and MaterialsAn in-house treatment planning software (TPS) was developed to perform intensity-modulated proton therapy (IMPT) FLASH-RT planning. Single-energy transmission proton PBS plans of 4.5 Gy × 15 fractions were optimized for seven consecutive hepatocellular carcinoma patients, using 2 and 5 fields combined with 1) the minimum MU/spot chosen between 100 and 400, and minimum spot time (MST) of 2 ms, and 2) the minimum MU/spot of 100, and MST of 0.5 ms, based upon considerations in target uniformities, OAR dose constraints, and OAR FLASH dose rate coverage. Then, the 3D average dose rate distribution was calculated. The dose metrics for the mean dose of Liver-GTV and other major OARs were characterized to evaluate the dose quality for the different combinations of field numbers and minimum spot times compared to that of conventional IMPT plans. Dose rate quality was evaluated using 40 Gy/s volume coverage (V40Gy/s).ResultsAll plans achieved favorable and comparable target uniformities, and target uniformity improved as the number of fields increased. For OARs, no significant dose differences were observed between plans of different field numbers and the same MST. For plans using shorter MST and the same field numbers, better sparing was generally observed in most OARs and was statistically significant for the chest wall. However, the FLASH dose rate coverage V40Gy/s was increased by 20% for 2-field plans compared to 5-field plans in most OARs with 2-ms MST, which was less evident in the 0.5-ms cases. For 2-field plans, dose metrics and V40Gy/s of select OARs have large variations due to the beam angle selection and variable distances to the targets. The transmission plans generally yielded inferior dosimetric quality to the conventional IMPT plans.ConclusionThis is the first attempt to assess liver FLASH treatment planning and demonstrates that it is challenging for hypofractionation with smaller fractional doses (4.5 Gy/fraction). Using fewer fields can allow higher minimum MU/spot, resulting in higher OAR FLASH dose rate coverages while achieving similar plan quality compared to plans with more fields. Shorter MST can result in better plan quality and comparable or even better FLASH dose rate coverage.

Standard approaches to the construction of maps of radioactive contamination do not provide errors in map data, so such maps do not, in fact, guarantee the accuracy of the map information. In this paper, based on the fact that the characteristics of radioactive contamination at a particular point in the territory have a lognormal probability distribution, a methodology for creating maps with a guaranteed confidence level of the provided information has been proposed and tested. There are considered two ways of creating maps, based on the results of "direct" measurements of radioactive contamination characteristics and in the combination of "direct" and "indirect" measurements of values statistically related to the mapping characteristic. The approaches and use of kriging methods proposed in the article allow to create maps with a given level of confidence and, accordingly, to take into account the risks caused by the uncertainty of measurements of radioactive contamination characteristics and uncertainty of their approximation.

Targeted radionuclide therapy (TRT) uses radiopharmaceuticals to specifically irradiate tumor cells while sparing healthy tissue. Response to this treatment highly depends on the absorbed dose. Tumor control probability (TCP) models aim to predict the tumor response based on the absorbed dose by taking into account the different characteristics of TRT. For instance, TRT employs radiation with a high linear energy transfer (LET), which results in an increased effectiveness. Furthermore, a heterogeneous radiopharmaceutical distribution could result in a heterogeneous dose distribution at a tissue, cellular as well as subcellular level, which will generally reduce the tumor response. Finally, the dose rate in TRT is protracted, relatively low, and variable over time. This allows cells to repair more DNA damage, which may reduce the effectiveness of TRT. Within this review, an overview is given on how these characteristics can be included in TCP models, while some experimental findings are also discussed. Many parameters in TCP models are preclinically determined and TCP models also play a role in the preclinical stage of radiopharmaceutical development; however, this all depends critically on the calculated absorbed dose. Accordingly, an overview of the existing preclinical dosimetry methods is given, together with their limitation and applications. It can be concluded that although the theoretical extension of TCP models from external beam radiotherapy towards TRT has been established quite well, the experimental confirmation is lacking. Thus, requiring additional comprehensive studies at the sub-cellular, cellular, and organ level, which should be provided with accurate preclinical dosimetry.

Background and Objective: Humans are always exposed to ionizing radiation that could potentially have harmful effects. The aim of this study was to evaluate the background gamma dose rate, the estimated annual effective dose, and the excess cancer risk assessment in Dargaz. Materials and Methods: This study was a cross sectional study which was conducted in January- March and July – September 2016. In this study, 5 stations (4 in the main geographical directions and 1 in the center city) were selected based on the map of the city to determine the dose rate of background gamma radiation in outdoor areas. A dosimeter was used (Geiger Müller detector STEP OD-02 with sensitivity of 0-2000 mSv/h) to measure gamma rays. The device was designed to monitore X-rays, gamma rays and beta rays. Results: The results showed that the maximum and minimum mean values of background gamma dose rate were 147±12 nSv/h and 113±11 nSv/h in the center and west-direction of the city, respectively. The annual effective dose for Dargaz residents in outdoor was determined to be 0/15 mSv/yr, and the amount of excess lifetime cancer risk was estimated as 0.6×10-3. Conclusion: The results indicated that there are significant differences between the rates dose in the center and other parts of the city (p≤0.05).

Abstract Background This study set out to evaluate the effect of dose rate on normal tissues (the lung, in particular) and the variation in the treatment efficiency as determined by the monitor unit (MU) and energy applied in Linac-based volumetric arc therapy (VMAT) total marrow irradiation (TMI). Methods Linac-based VMAT plans were generated for the TMI for six patients. The planning target volume (PTV) was divided into six sub-volumes, each of which had their own isocenter. To examine the effect of the dose rate and energy, a range of MU rates (40, 60, 80, 100, 300, and 600 MU/min) were selected for 6, 10, and 15 MV. All the plans were verified by portal dosimetry. Results The dosimetric parameters for the target and normal tissue were consistent in terms of the energy and MU rate. The beam-on time was changed from 59.6 to 6 min for 40 and 600 MU/min. When 40 MU/min was set for the lung, the dose rate delivered to the lung was less than 6 cGy/min (that is, 90%), while the beam-on time was approximately 10 min. The percentage volume of the lung receiving 20 cGy/min was 1.47, 3.94, and 6.22% at 6, 10, and 15 MV, respectively. However, for 600 MU/min, the total lung volume received over 6 cGy/min regardless of the energy, and over 20 cGy/min for 10 and 15 MV (i.e., 54.4% for 6 MV). Conclusions In TMI treatment, reducing the dose rate administered to the lung can decrease the incidence of pulmonary toxicity. To reduce the probability of normal tissue complications, the selection of the lowest MU rate is recommended for fields including the lung. To minimize the total treatment time, the maximum MU rate can be applied to other fields.

Introduction:F-18 radioisotope has higher photon energy when compared with other radioisotopes that are preferred in conventional imaging procedures in nuclear medicine. The aim of this study was to measure external radiation dose rate from patients injected with F-18 fluorodeoxyglucose (FDG) and to determine appropriate discharge time after F-18 FDG positron emission tomography/computed tomography (PET/CT) procedure.Methods:Our study included 29 (M/F=9/20) patients who were referred to nuclear medicine department for F-18 FDG PET/CT imaging. Dose rates were measured at a distance of 0, 0.5, 1, 1.5 and 2 m from patients via Geiger-Müller probe at 3 different time points: 1) Just after the intravenous injection of F-18 FDG, 2) before PET/CT imaging and 3) just before discharge of patients from PET/CT department. Statistical analysis was performed to evaluate the differences between measurements.Results:Patients were injected 291±62 megabecquerel (MBq) (range: 226-440 MBq) F-18 FDG via IV route. The patients stayed in nuclear medicine department for 70.3±13.8 min (range: 53 min-100 min) after injection of F-18 FDG. Radiation dose velocity measurements taken at a distance of 1 meter were 39.7±11.9 μSv/h just after the injection, 21.1±4.5 μSv/h before PET/CT examination and 14.3±2.9 μSv/h just before discharge.Conclusion:Although F-18 has high photon energy, its halflife is relatively short and this makes F-18 FDG an ideal radiopharmaceutical for PET/CT imaging. When the PET/CT scan is terminated, the dose rate measurements of the patients at a distance of 1 m are appropriate for discharge according to Turkish Atomic Energy Authority regulations. Therefore, patients can be safely discharged by explaining the necessary radiation safety measures after completing F-18 FDG PET/CT imaging.

In this paper we will introduce several physical parameters that are very promising to use as indicators to diagnose and prognose tissue, cellular and molecular status. Relaxation time, DC conductivity, activation energy and enthalpy of the haemoglobin (Hb) molecule are introduced as key parameters to detect changes in the polarizability of Hb relating this change to the state of the molecule. Using dielectric and impedance measurements, we fitted the relaxation peaks found within the frequency and temperature windows to the proper equations to get our pre-mentioned parameters. Activation energy, Ea, and enthalpy change, ΔH, are also calculated. Results of higher dose rate (HDR) and lower dose rate (LDR) had different patterns for most parameters. Relaxation time and dc conductivity are sensitive to the electrical homogeneity of the Hb. Activation, E, and enthalpy change are sensitive to the damage of the Hb molecule. Early diagnosis and prognosis differentiating between higher and lower dose rates used is possible. Dielectric parameters represent promising biophysical markers for diagnosis and prognosis of radiation exposure.

Systematic studies on the accumulation of210Po in 12 medicinal plants and activity concentration in associated soils have been carried out. The activity of210Po was measured using a ZnS (Ag) alpha counting system. The mean210Po activity concentration was found to be 27.8 and 8.3 Bq/kg for plant and soil, respectively. The plant-to-soil mean activity ratio of210Po was found to be 3.8. A good correlation was observed between the activity concentration of210Po in plant and soil. The absorbed gamma dose rates in the study area were also measured using a portable scintillometer and found to vary in the range of 34.8–52.2 nGy/h, with a mean value of 43.5 nGy/h. The results of these systematic investigations are presented and discussed in detail.

Introduction: This Study has was carried out to measure and detect the natural occurred radionuclide content including 226Ra, 232Th and 40K in the Nile River sediments at various locations in Upper Egypt, from Aswan to El-Minya. Additionally, we determine the absorbed dose rate, the annual effective dose equivalent, and excess lifetime cancer risk also has been calculated. Material and Methods: The gamma ray measurements were performed with a high resolution High-Purity Germanium detector, low background, and Personal Computer multichannel analyzer. Results: In Aswan Governorate, the mean specific activities of radionuclide's (226Ra,232Th and 40K) 14.86, 13.78 and 175.4 in Bq/kg respectively. In Qena Governorate, the mean specific activities of mentioned radionuclides were 14.44 Bq/kg, 15.02 Bq/kg and 197.57 Bq/kg, respectively. These values were18.53 Bq/kg, 11.3 Bq/kg and 184.73 Bq/kg in Sohag Governorate, respectively. In Asyut Governorate the mean specific activities of the radionuclide's were 11.38 Bq/kg, 10.0 Bq/kg, and 164.715 Bq/kg, respectively. However, these values were 19.56 Bq/kg, 11.72 Bq/kg, and 239.92 Bq/kg in Minya Governorate, respectively. The hazard indices of gamma radiation such as Absorbed dose rate, annual effective dose equivalent and excess lifetime cancer risk were calculated. Conclusion: According to the results, all the values were within the reported values by the United Nations Scientific Committee on the Effects of Atomic Radiation. In addition, there was no likelihood of radiological health hazards to the population living close to the Nile river.

The indoor low gamma dose rate exposures due to Egyptian room building materials are assessed by means of three different techniques: experimentally by using a thermoluminescent dosimeter, theoretically by using the general room model and by the Monte Carlo simulation through the RESRAD-BUILD software. The present study aims at validating the theoretical methods so that it can be amply used for measuring the low dose rates usually associated with the building materials. The measured in door dose rates were in the range of 55.92 ± 14.47 to 86.89 ± 16.68 nGyh–1 de pending on the position inside the room as obtained by the thermoluminescent dosimeter after 5 months' accumulation. Lower dose rates are obtained near the door and windows while higher dose rates are obtained at the center of the room, and close to the extended walls. Comparable results of the dose rates at same positions inside the room are obtained by the RESRAD-BUILD software. The room model is restricted to the room center and also gives comparable results. The three methods showed comparable results, which in turn confirm the recommendation of using theoretical ones, with RESRAD-BUILD software being more accurate.

Accurate knowledge of the relative biological effectiveness (RBE) and its dependencies is crucial to support modern ion beam therapy and its further development. However, the influence of different dose rates of the reference radiation and ion beam are rarely considered. The ion beam RBE-model within our “UNIfied and VERSatile bio response Engine” (UNIVERSE) is extended by including DNA damage repair kinetics to investigate the impact of dose-rate effects on the predicted RBE. It was found that dose-rate effects increase with dose and biological effects saturate at high dose-rates, which is consistent with data- and model-based studies in the literature. In a comparison with RBE measurements from a high dose in-vivo study, the predictions of the presented modification were found to be improved in comparison to the previous version of UNIVERSE and existing clinical approaches that disregard dose-rate effects. Consequently, DNA repair kinetics and the different dose rates applied by the reference and ion beams might need to be considered in biophysical models to accurately predict the RBE. Additionally, this study marks an important step in the further development of UNIVERSE, extending its capabilities in giving theoretical guidance to support progress in ion beam therapy.

The ongoing trend in the development of powerful ultrashort pulse lasers has attracted increasing attention for this technology to be applied in large-scale surface engineering and modern microfabrication. However, the emission of undesired X-ray photon radiation was recently reported even for industrially relevant laser irradiation regimes, causing serious health risks for laser operators. In the meantime, more than twenty influencing factors have been identified with substantial effects on X-ray photon emission released by ultrashort pulse laser processes. The presented study on enhanced X-ray emission arising from high pulse repetition frequency ultrashort pulse laser processing provides new insights into the interrelation of the highest-contributing parameters. It is verified by the example of AISI 304 substrates that X-ray photon emission can considerably exceed the legal dose rate limit when ultrashort laser pulses with peak intensities below 1 × 1013 W/cm² irradiate at a 0.5 MHz pulse repetition frequency. The peak intensity threshold value for X-ray emissions decreases with larger laser spot sizes and longer pulse durations. Another key finding of this study is that the suction flow conditions in the laser processing area can affect the released X-ray emission dose rate. The presented results support the development of effective X-ray protection strategies for safe and risk-free ultrashort pulse laser operation in industrial and academic research applications.

Objective To investigate the effects of high-energy X-rays irradiation at different dose rates on the plating efficiency, survival fraction and radiobiological parameters of cervical cancer HeLa cell line. Methods Human cervical cancer Hela cell line in exponential growth phase were treated with 0, 1, 2, 4, 6, 8Gy at 2, 6, 10Gy/min dose rates. After irradiation for 12 days in the incubator, 0.5% crystal violet staining was fixed, and the number of clones larger than 50 cells was counted. The data was analyzed and dose-survival curves were plotted following the standard linear-quadratic model using GraphPad Prism 5.0 software to get the values of radiobiological parameters. Differences of survival fraction with different dose rates were tested with analysis of variance by SPSS19.0 software. Results After 2, 6, 10 Gy/min of high-energy X-rays irradiation, the differences between the plating efficiency and survival fraction of HeLa cells were statistically significant (P=0.03 and 0.04). The average α/β values were 3.28Gy, 3.35Gy, 3.93Gy, SF2 were 0.79, 0.78, 0.75. Three dose rates showed no statistically significant difference in the biological parameters, α/β, D0, Dq or SF2 (P > 0.05). Conclusion With the increasing dose rate of high-energy X-rays (2, 6, 10Gy/min), the survival rate of HeLa cells gradually decreases while the biological effect gradually increases.

O Depósito Inicial de Resíduos Radioativos de Baixa Atividade - DIRBA é uma instalação auxiliar à Fábrica de Combustível Nuclear - FCN para o armazenamento inicial dos rejeitos radioativos de baixa geração gerado no ciclo do combustível nuclear sob responsabilidade da FCN. Atualmente são armazenados aproximadamente 460 tambores de 200 litros contendo resíduos Classe 2.3: Resíduos contendo Radionuclídeos Naturais (RBMN-RN). Como parte do licenciamento nuclear da instalação, um programa de monitoramento radiológico da área foi desenvolvido com monitoramento mensal de 17 pontos de exposição, 3 pontos de amostragem direta de longa distância com monitores CAM alfa-7, monitorados em janeiro e 9 pontos onde manchas de alfa emissores de meia-vida longa foram monitorados em janeiro.A taxa média de exposição entre os pontos foi de 0,5 μSv ∙ h -1 , com um máximo de 1,27 μSv ∙ h -1 variando, em média, entre 0,98 μSv ∙ h -1 no ponto P1 a 0 , 23 μSv ∙ h -1 no P11. A média mensal foi a mesma, 0,50 μSv ∙ h -1 , variando de 0,46 μSv ∙ h -1 (novembro) a 0,57 μSv ∙ h -1 (agosto). Como a alfa de meia-vida de longa duração estava todas abaixo do MDA, bem como os 9 esfregaços. Em relação às exigências das áreas monitoradas, o depósito deve ser considerado como área supervisionada, do ponto de vista da radioproteção.A possibilidade de tombamento dos tambores ou outros acidentes com derramamento de material neles contido fez com que, de forma proativa, uma área considerada considerada área controlada.

Since the discovery of cosmic radiation by Victor Hess in 1912, when he reported a significant increase in radiation as altitude increases, concerns about radiation effects on human bodies and equipment have grown over the years. The secondary and tertiary particles which result from the interaction of primary cosmic rays with atmospheric particles and commercial aircraft components, are the primary cause of the radiation dose deposited in human bodies and in electronic equipment (avionics) during aircraft flights. At an altitude of about 10 km (or higher) above sea level, the dose received by frequent flyers, and especially flight crew, is a serious concern. Also of concern is the possible failure of sensitive equipment on board commercial aircrafts as a result of flying through this mixed radiation field. Monitoring radiation in the atmosphere is therefore very important. Here we report on the first measurements by the High Altitude Radiation Monitor (HARM) detector during a commercial flight from Johannesburg (O.R. Tambo International Airport) to Windhoek (Hosea Kutako International Airport). As part of a public awareness activity, the HARM detector was placed on a high-altitude balloon, and these measurements are also shown here. Model calculations (estimations) of radiation levels for the commercial aircraft flight are shown and the results are used to interpret our measurements. Significance: • Measurements of the Regener–Pfotzer maximum in South Africa and dosimetric measurements on board a commercial flight are presented. • These radiation measurements are compared to model calculations which can be used to predict the radiation dose during commercial flights. • This study also aims to raise public awareness about the atmospheric radiation environment from ground level to the Regener–Pfotzer peak at high altitude.

In this study, mass activity of naturally occurring radioactive materials were measured in twenty-three building material samples, use extensively in the area exposed to a high level of natural background radiation (Mahallat, Iran), to determine the radioactivity index and changes to the level of indoor gamma radiation. The mass activity of 232Th, 226Ra and 40K were within the ranges from 18 ± 3 to 44 ± 10 Bq/kg (average of 27 ± 6 Bq/kg), 22 ± 5 to 53 ± 14 Bq/kg (average of 34 ± 6 Bq/kg) and 82 ± 18 to 428 ± 79 Bq/kg (average of 276 ± 58 Bq/kg), respectively. The gamma dose rates for population were estimated between 48 ± 9 and 111 ± 26 nGy/h with exception of radon exhalation from building materials. Since the air kerma rate in the town varies from 0.8 to 4 μGy/h, the attenuation coefficient was calculated for buildings made of the aforementioned materials. Additionally, the annual gamma radiation doses for inhabitants were calculated based on time spent outdoors and indoors.

In this study, three different sliding bearing alloy samples were investigated in terms of their performance on attenuation characteristics and behavioral attitudes under 0.015–15 MeV gamma-ray exposure. Accordingly, different types of advanced calculation methods were utilized to calculate the radiation shielding parameters. Next, several gamma-ray shielding parameters and exposure rates in addition to fast neutron removal cross-section were determined. Furthermore, exposure and energy absorption buildup factors were determined by using G-P fitting method. Mass attenuation coefficients (MAC) values were recorded as 2.5246, 2.5703, and 2.5827 (cm2/g) for Alloy1, Alloy2, and Alloy3 samples at 15 MeV photon energy, respectively. At 40 mfp, the highest EBF values were reported as 1,376,274, 1,003,593, and 969,373 for Alloy1, Alloy2, and Alloy3 samples. The results of this extended investigation showed that the Alloy3 sample with the highest Pb reinforcement amount has superior shielding capability among the investigated samples. It can be concluded from the results that substitution of Pb with Bi in the recent alloy structure has a monotonic effect on different types of shielding parameters. Therefore, it can also be concluded that Pb is a remarkable tool for the improvement of the shielding properties of studied alloy structures.

A CS-30 cyclotron has been in operation at King Faisal Specialist Hospital and Research Center (KFSHRC) since 1982. The CS-30 cyclotron has been used to produce medical radioisotopes for positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Some of the nuclear reactions of radionuclide production are associated with the intense release of a wide range of fast neutrons. In this work, we investigated the radionuclides produced from neutron interactions with the cyclotron facility walls. Activation isotopes were determined by performing gamma ray spectrometry utilizing a high-purity germanium (HPGe) detector. The major radionuclides found were 152Eu, 154Eu, 134Cs, 65Zn and 60Co. Activation isotope accumulation had increased the dose rate inside the facility. The surface dose rates were measured at all of the surrounding walls. The maximum surface dose rate was found to be 1.2 µSv/h, which is much lower than the permissible occupational exposure of 15 µSv/h based daily 5 work hours.

The results of modeling the conversion factor from rainfall-deposited unit activity of gamma-emitting radon and thoron daughter decay products to their created gamma-radiation dose rate as a function of height above the Earth’s surface using the Geant4 toolkit are presented in this paper. Thin layers of water, soil, and air, with the height of 0.1–10 mm, are considered as the source in order to examine whether the composition of the radiation source environment affects the simulation result. Cases with different absorber-atmosphere densities are simulated. The contribution of each radionuclide 212Bi, 214Bi, 212Pb, 214Pb and 208Tl to the total gamma background was determined. The dependence of dose rate growth during the precipitation period on the detector position in relation to the area covered by precipitation was investigated numerically. The obtained conversion factors are universal values, because do not depend on soil type (material) on which radionuclides are deposited by precipitation. These coefficients can be used for solving both direct tasks of radiation background recovery during precipitation and inverse tasks of determining the intensity and amount of precipitation by the known gamma background, as well as tasks to decipher the gamma background by the shape of the response to various phenomena. Also in this work, it is shown how thoron decay products can affect the response shape of gamma background on atmospheric precipitation.

Testing cell a hot cell is responsible for inspecting the spent fuel elements in open pool type reactor. Because the spent fuel elements examination in the testing cell would result in rising in radiation dose level, a previous precaution should be estimated to ensuring the radiation protection safety and the prevention of radiation hazard for the workers during the process. The most efficient precaution against these kinds of work is the estimation of the predicted radiation dose level around the hot cell during the inspection process. In this regard, a MCNP model was performed to simulate the spent fuel element inspection inside the hot cell to estimate the radiation dose level around the testing cell during the process. The dose rate, during the inspection of the spent fuel element, would be estimated at different decay times for different burn-up. The calculations show that the minimal decay times required to manipulating the spent fuel element would range between 120 to 270 days for burn-up ranging between 18745 and 101224.4 MWD/TU.

The controversy of adjuvant radiotherapy of meningiomas is at least partially due to the insufficient understanding on meningioma cells' response to irradiation and the shortage of radiosensitivity-promotion methods. MicroRNA-221 and microRNA-222 were identified as critical regulators of radiosensitivity in several other tumors. However, their effect in meningiomas has yet to be confirmed. Therefore, the malignant meningioma IOMM-Lee cells were adopted, transfected with microRNA-221/222 mimics or inhibitors, and irradiated with different dosages. The effects of radiation and microRNA-221/222 were then assessed in vitro and in vivo. Radiation dose increases and microRNA-221/222 downregulation synergistically inhibited cell proliferation and colony formation, prevented xenograft tumor progression, and promoted apoptosis, but antagonistically regulated cell invasiveness. Pairwise comparisons revealed that only high-dose radiations (6 and 8 Gy) can significantly promote cell invasiveness in comparison with unirradiated counterparts. Further comparisons exhibited that downregulating the microRNA-221/222 expression can reverse this radiation-induced cell invasiveness to a level of untransfected and unirradiated cells only if cells were irradiated with no more than 6 Gy. In addition, this approach can promote IOMM-Lee's radiosensitivity. Meanwhile, we also detected that the dose rate of irradiation affects cell cycle distribution and cell apoptosis of IOMM-Lee. A high dose rate irradiation induces G0/G1 cell cycle arrest and apoptosis-promoting effect. Therefore, for malignant meningiomas, high-dose irradiation can facilitate cell invasiveness significantly. Downregulating the microRNA-221/222 level can reverse the radiation-induced cell invasiveness while enhancing the apoptosis-promoting and proliferation-inhibiting effects of radiation and promoting cell radiosensitivity.

Abstract Background This study evaluated the effect of radiation dose rate in patients with hematolymphoid malignancies undergoing myeloablative conditioning with total body irradiation (TBI), for hematopoietic stem cell transplantation. Methods The incidence of pulmonary toxicity (PT) and treatment efficacy were compared between the conventional (≥ 6 cGy/min) and reduced dose rate (

Introduction: Nuclear radiation is potentially harmful to humans and soil contamination with radionuclides is the main source of human radiation exposure. These radionuclides can., enter to human body through the food chain. In this study, 34 soil samples were collected from between Arak city and Shazand Power Plant over 20 km length and analyzed. Materials and Methods: The specific activities of 226Ra, 232Th, 40K, and 137Cs were measured in soil samples, using gamma-ray spectrometry and a high-purity germanium (HPGe) detector. For all the samples, we calculated radiological hazards such as radium equivalent (Raeq), dose rate in air (D), internal and external hazard indices (Hin, Hex), annual gonadal dose equivalent (AGDE), and excess lifetime cancer risk. Results: The specific activities of 226Ra, 232Th, 40K, and 137Cs in the soil samples varied from 18.92 to 43.11, 25.31 to 54.27, 230.17 to 728.25, and from in and Hex wereless than unity. Excess lifetime cancer risk of the samples ranged from 0.21×10-3 to 0.31×10-3, which are close to the mean world value (0.29×10-3) butlower than the acceptable value (10-3). Conclusion: The radiological parameters estimated from the specific activities of the radionuclides in soil were within the acceptable range, and therefore, radiation exposure poses no significant risks to the resident population in the vicinity of the power plant.

Abstract Background Prostate-specific membrane antigen (PSMA)-targeted therapy with 177Lu-PSMA-617 is a therapeutic option for patients with metastatic castration-resistant prostate cancer (mCRPC). To optimize the therapy procedure, it is necessary to determine relevant parameters to define radiation protection and safety necessities. Therefore, this study aimed at estimating the ambient radiation exposure received by the patient. Moreover, the excreted activity was quantified. Results In total, 50 patients with mCRPC and treated with 177Lu-PSMA-617 (mean administered activity 6.3 ± 0.5 GBq) were retrospectively included in a bi-centric study. Whole-body dose rates were measured at a distance of 2 m at various time points after application of 177Lu-PSMA-617, and effective half-lives for different time points were calculated and compared. Radiation exposure to the public was approximated using the dose integral. For the estimation of the excreted activity, whole body measurements of 25 patients were performed at 7 time points. Unbound 177Lu-PSMA-617 was rapidly cleared from the body. After 4 h, approximately 50% and, after 12 h, approximately 70% of the administered activity were excreted, primarily via urine. The mean dose rates were the following: 3.6 ± 0.7 μSv/h at 2 h p. i., 1.6 ± 0.6 μSv/h at 24 h, 1.1 ± 0.5 μSv/h at 48 h, and 0.7 ± 0.4 μSv/h at 72 h. The mean effective half-life of the cohort was 40.5 ± 9.6 h (min 21.7 h; max 85.7 h). The maximum dose to individual members of the public per treatment cycle was ~ 250 ± 55 μSv when the patient was discharged from the clinic after 48 h and ~ 190 ± 36 μSv when the patient was discharged after 72 h. Conclusions In terms of the radiation exposure to the public, 177Lu-PSMA is a safe option of radionuclide therapy. As usually four (sometimes more) cycles of the therapy are performed, it must be conducted in a way that ensures that applicable legal requirements can be followed. In other words, the radiation exposure to the public and the concentration of activity in wastewater must be sub-marginal. Therefore, in certain countries, hospitalization of these patients is mandatory.