Effective Radiation Dose Research Articles

Результаты контроля радона в жилых домах вблизи разработки Шкурлатовского месторождения гранита

The presence of acting granite quarrying near the residential area may cause increase in indoor radon concentration. The paper presents results of estimating the level of radiation and carcinogenic danger for residents living near the acting Shkurlatov granite deposit. To assess average annual equivalent equilibrium volume activity (EEVA), Bq/m3, and the average annual individual effective radiation doses from radon isotopes presented in the indoor air, mSv/year, the data of the unified system for individual doses monitoring from 2017 through 2022 were used. Results of voluntary in-situ examination and 42 measures of radon volume activity in 17 residential buildings the closest to the granite quarry, were carried out in 2023. The above measures were used for calculation of EEVA of radon isotopes (Bq/m3) and the average annual individual effective radiation dose to the residents inhalated indoor radon (mSv/year). According to the data on radon monitoring in the dwellings situated near the Shkurlatov granite deposit the EEVA in wooden houses varied from 9.2 to 35.5 Bq/m3, EEVA in stone houses varied from 9.4 to 41.4 Bq/m3, average values are 21.22.0 and 21.91.8. The quoted values do not differ from the monitoring data in the Pavlovsk district of the Voronezh Region. Statistic data on malignant neoplasms incidence from 2017 through 2022 were investigated. As for the incidence of trachea, bronchus and lung cancer, no statistically significant difference between average multiyear cancer incidence in the area close to the Shkurlatov granite deposit in Pavlovsk district, Voronezh region, and in the more favorable district. The comparison was based on annual radiation doses due to radon isotopes inhalation. The results of the study suggest that radon at the registered indoor concentration does not affect cancer incidence among people living near the Shkurlatov granite deposit.

Radiation Dose Reduction through the Optimization of Mask Images in Cerebral Angiography

To verify the effectiveness of optimizing the number of mask images in DSA for radiation dose reduction during cerebral angiography. A total of 60 angiography sessions in 2 times for 30 patients performed by the same operator were included in this study. In order to compare the effects of optimization to change the injection delay time of DSA from 1 s to the shortest possible time, the number of mask images, the number of imaging frames, and radiation doses between sessions were compared and analyzed retrospectively. In one DSA run, the number of mask images was decreased from 6 (5-7) to 3 (2-3) frames (p<0.01)/57.1% (median [IQR]/reduction rate), the number of imaging frames was decreased from 34 (32-36) to 32 (29-34) frames (p<0.01)/7.9%, and the radiation dose was decreased from 33 (23-47) to 30 (21-40) mGy (p<0.01)/8.3%. In magnification angiography, the reductions rate was significantly increased. In one angiography session, the number of mask images was decreased from 45 (35-72) to 19 (16-34) frames (p<0.01)/54.6%, the number of imaging frames was decreased from 242 (199-385) to 211 (181-346) frames (p<0.01)/8.3%, the radiation dose of DSA was decreased from 295 (190-341) to 242 (167-305) mGy (p<0.01)/11.6%, and the total radiation dose was decreased from 369 (259-418) to 328 (248-394) mGy (p<0.01)/7.5%. Using the shortest possible injection delay time for the number of mask image optimization was an effective radiation dose reduction method.

Assessment of lipid and carbohydrate metabolism in the population of South Yakutia by the effective radiation dose level

Assessment of lipid and carbohydrate metabolism in the population of South Yakutia by the effective radiation dose level

Radiotherapy and blockade of immune checkpoints in treatment of cancer patients

Background. Immunotherapy, which aims to use immune defense mechanisms to fight cancer, is a new area of anticancer treatment. A major breakthrough in tumor immunotherapy was the discovery of immune checkpoint proteins, which act as powerful suppressors of the immune system. Humanized monoclonal antibodies, which target these proteins, have proven to be clinically effective in patients with different types of cancer. However, the majority of patients do not respond to checkpoint inhibitor therapy, which necessitates the use of combination strategies to overcome resistance to immunotherapy. In recent years, the combination of radiotherapy and immune checkpoint inhibitors has attracted considerable attention and has been widely studied in preclinical and clinical trials. Much attention is given to the optimization of combined treatment regimens. However, the optimal radiation dose, fractionation scheme, radiation volumes, and radiation sequence in checkpoint inhibitor treatment still remain unclear. Purpose – to analyze and summarize data from preclinical and clinical trials aimed at solving problems related to the choice of optimal doses, fractionation, radiation volume, and sequencing of checkpoint inhibitor immunotherapy and radiotherapy. Materials and methods. For data search, we used Cochrane library and databases (Pubmed, Scopus, Google Scholar). The results of the studies published over the period from 2008 to 2023 were analyzed. Results and discussion. The evidence of the rationality of combining radiotherapy and checkpoint inhibitors in the treatment of cancer patients is shown. The data on the effects of radiation dose and fractionation on antitumor immune responses were analyzed. The results of works that deal with the search for the optimal sequence of radiotherapy and immune checkpoint inhibitors and the selection of the irradiation volume necessary for the generation of an effective systemic antitumor immune response are considered. Conclusions. Combined treatment with radiation therapy and immune checkpoint inhibitors is a promising strategy for patients with metastatic tumors. Preclinical and clinical data indicate that different radiation regimens can cause different effects on antitumor immunity. Further studies of doses and fractionation regimens of radiation therapy, irradiation volume, and the optimal time for each component of combination therapy are needed to determine the conditions for maximizing the immune response. The obtained results will help optimize the combination treatment regimens and wider implementation of such treatment in clinical practice.

Gamma radiation effect on the structural and optical properties of CdS thin films prepared by spray pyrolysis technique

One way to increase the solar cell efficiency is to increase the range of transmitted visible light throughout the window layer. This could be achieved via broadening its band gap; an aim that could be attained through doping and/or irradiation technique. In this way, cadmium sulfide (CdS) thin films have been successfully prepared on pre-heated glass substrates at 400 °C by spray pyrolysis technique and the effect of gamma radiation dose on the structural and optical properties of CdS thin films has been investigated in the range of 250 to 450 Gy. The XRD results manifest the formation of hexagonal phase of CdS with a crystallite size of 58.73 nm, which decreased to 47.26 nm after exposure to 350 Gy. Also, the SEM micrographs show the formation of some randomly oriented groups of nano-rods on the surface of highly condensed nanorods of CdS thin film. The optical investigation illustrates that a blue shift in the optical gap from 2.4 to 3.34 eV has been occurred as the radiation dose reached 350 Gy. The sensitivity of the films to the applied dose has approached 0.005 eV/Gy. Moreover, the shifted band gap exhibited less fading up to 74 days.

Instrumental study of radiation doses and working conditions for personnel of X-ray surgical teams

The purpose of the study was an experimental assessment of the conditions for the formation and values of equivalent doses of irradiation of the lenses of the eyes, as well as the effective doses of irradiation of personnel in X-ray operating rooms of a cardiological profile. Particular attention to the control of eye lens irradiation is due to the need to harmonize domestic regulatory documents with the new IAEA safety standard GSR Part 3. The study was performed using a complex phantom, including an anthropomorphic phantom of a human head and a water phantom imitating the torso of an X-ray surgical team member. The results of assessments of individual eye lens irradiation doses, obtained both on the basis of integrated measurements by thermoluminescent dosimetry methods, and by calculation based on measurements of the ambient dose equivalent rate at the personnel workplaces, showed that at the maximum operating parameters of the X-ray tube (high voltage and a large number of frames per second), annual doses to the lenses of the eyes, even for assisting personnel, may exceed the new recommended dose limit of 20 mSv. The assessment of the ratio between the doses of irradiation of the whole body (chest), neck and lenses of the eyes showed the possibility of estimating the doses of irradiation of the lenses of the eyes of the assisting personnel of X-ray surgical teams using a thermoluminescent dosimeter placed over a protective apron in the neck area. For the category of personnel under consideration, the priority is to control the irradiation of the lenses of the eyes, and not the whole body.

An evaluation of CT radiation doses within the Yorkshire Lung Screening Trial.

To evaluate radiation doses for all low-dose CT scans performed during the first year of a lung screening trial. For all lung screening scans that were performed using a CT protocol that delivered image quality meeting the RSNA QIBA criteria, radiation dose metrics, participant height, weight, gender, and age were recorded. Values of volume CT dose index (CTDIvol) and dose length product (DLP) were evaluated as a function of weight in order to assess the performance of the scan protocol across the participant cohort. Calculated effective doses were used to establish the additional lifetime attributable cancer risks arising from trial scans. Median values of CTDIvol, DLP, and effective dose (IQR) from the 3521 scans were 1.1mGy (0.70), 42.4mGycm (24.9), and 1.15mSv (0.67), whilst for 60-80kg participants the values were 1.0mGy (0.30), 35.8mGycm (11.4), and 0.97mSv (0.31). A statistically significant correlation between CTDIvol and weight was identified for males (r = 0.9123, P < .001) and females (r = 0.9052, P < .001), however, the effect of gender on CTDIvol was not statistically significant (P = .2328) despite notable differences existing at the extremes of the weight range. The additional lifetime attributable cancer risks from a single scan were in the range 0.001%-0.006%. Low radiation doses can be achieved across a typical lung screening cohort using scan protocols that have been shown to deliver high levels of image quality. The observed dose levels may be considered as typical values for lung screening scans on similar types of scanners for an equivalent participant cohort. Presentation of typical radiation dose levels for CT lung screening examinations in a large UK trial. Effective radiation doses can be of the order of 1mSv for standard sized participants. Lifetime attributable cancer risks resulting from a single low-dose CT scan did not exceed 0.006%.

Analysis of Scattered Radiation Dose in Cardiac Catheterization Examination in the Cathlab Room Using TLD

The problem: About 75% of the information humans receive visually or through the eyes. However, the eye cannot detect all types of light, including X-ray radiation. There are parts of the human body organs are very sensitive to X-ray radiation, because of the risk of damaging tissues and triggering causing ery, infertility or cataracts. Today, X-rays have become the backbone of the development of radiology equipment, especially for producing. One of them is C-Arm equipment technology, which is able to image three-dimensional patient objects in real time with fluoroscopy techniques. This study aims to obtain and evaluate the effective radiation dose received by medical personnel working in the cathlab room area when radiation workers during cardiac catheterization is performed. Observations were made in 10 radiation measurement areas, namely the radiographer operator area, the area in and out of medical personnel, the area in and out of patients, the Pb glass area in the operator room, the Pb glass area in the Cathlab examination room, the area where TLD measurements are placed waist-high doctors, nurses and radiographers work during the installation of the heart ring, the floor area near the X-ray source, and the wall area in the Cathlab examination room. The main tool uses C-Arm modality, and TLD detector chips. The object of observation is the radiation source area consisting of one doctor, one radiographer and one nurse. Catheterization was performed on 10 patients with different examination times. Research results: operator area; the effective dose received was 0.000 mSv, doctors ranged from 1.136 to 3.608 mSv, while nurses ranged from 0.194 mSv to 2.270 mSv, while radiographers ranged from 0.074 mSv to 0.126 mSv, while patient entrance and exit areas ranged from 0.00 mSv to 0.0127 mSv, while nurses in and out of medical personnel ranged from 0.005 mSv to 0.057 mSv, Measurements on the floor near the radiation source/floroscopy range from 0.036 mSv to 0.074 mSv. Cathlab indoor wall measurement results range from 0.031 mSv to 0.103 mSv. Within 1 year, the dose in the operator room is 0.00 mSv, the dose received by doctors ranges from 230.4 to 1209.5 mSv/hour, radiographers between 128.2 mSv to 1812.4 mSv and nurses between 115.2 mSv to 2448.2 mSv. In the area of the patient entrance and exit between 0.00 mSv to 38.8 mSv, the area of the patient entrance and exit between 72.00 mSv to 82.2 mSv, and the floor area near the radiation source/floroscopy between 518.2 mSv to 1065.2 mSv, as well as the inner wall area of the cathlab chamber between 44.6 mSv to 148.32 mSv. It was found that; The effective dose received in one year received by doctors, nurses and radiographers who work close to radiation sources (floroscopy) results are higher than the dose value set by PERKA BAPETEN No. 8 of 2011 which is 20 mSv and ICRP 203 which is 500 mSv per year.

Low-dose versus conventional CT urography using dual-source CT with different time-current product values and the same tube voltage: image quality and diagnostic performance in various diagnoses.

To compare the image quality and diagnostic performance of low-dose CT urography to that of concurrently acquired conventional CT using dual-source CT. This retrospective study included 357 consecutive CT urograms performed by third-generation dual-source CT in a single institution between April 2020 and August 2021. Two-phase CT images (unenhanced phase, excretory phase with split bolus) were obtained with two different tube current-time products (280 mAs for the conventional-dose protocol and 70 mAs for the low-dose protocol) and the same tube voltage (90 kVp) for the two X-ray tubes. Iterative reconstruction was applied for both protocols. Two radiologists independently performed quantitative and qualitative image quality analysis and made diagnoses. The correlation between the noise level or the effective radiation dose and the patients' body weight was evaluated. Significantly higher noise levels resulting in a significantly lower liver signal-to-noise ratio and contrast-to-noise ratio were noted in low-dose images compared to conventional images (P < .001). Qualitative analysis by both radiologists showed significantly lower image quality in low-dose CT than in conventional CT images (P < .001). Patient's body weight was positively correlated with noise and effective radiation dose (P < .001). Diagnostic performance for various diseases, including urolithiasis, inflammation, and mass, was not different between the two protocols. Despite inferior image quality, low-dose CT urography with 70 mAs and 90 kVp and iterative reconstruction demonstrated diagnostic performance equivalent to that of conventional CT for identifying various diseases of the urinary tract. Low-dose CT (25% radiation dose) with low tube current demonstrated diagnostic performance comparable to that of conventional CT for a variety of urinary tract diseases.

IMPACT OF LEGISLATIVE CHANGE ON THE CLASSIFICATION OF RAW MATERIALS AND BUILDING MATERIALS IN TERMS OF NATURAL RADIOACTIVITY

Natural radioactivity is present in the human environment to a greater or lesser extent, also in varioustypes of raw or building materials. Monitoring of the concentration of natural radioactive isotopesof potassium 40K, radium 226Ra and thorium 228Th or 232Th in samples of raw and/or constructionmaterials allows assessing the exposure of people to ionizing radiation emitted by these materials.Exceeding the limit value of the radioactive concentration index for raw and/or building materials,defined in the Ordinance of the Council of Ministers (Polish Journal of Laws/Dz.U. No. 33/2021),may result in an effective radiation dose greater than 1 mSv/year – the dose limit for the population.In Poland, pertinent legislation requiring the establishing of the natural radioactivity of raw and/orbuilding materials dates back to the 1970s and has been changed several times by now. However, themost significant changes in the legislation have occurred recently. Due to the obligation of imposingthe application of the provisions of the of European Council 2013/59/EURATOM of 5 December2013 laying down basic safety standards for protection against risks arising from exposure to theeffects of ionizing and repealing Directives 89/618/Euratom, 90/641/ Euratom, 96/29/Euratom,97/43/Euratom and 2003/122/Euratom (the so-called BSS version), it was necessary to adopt theamendment to the Atomic Law. The implementation of the BSS Directive in Poland was issued on thebasis of the resolution of the Parliament of June 13, 2019 amending the Atomic Law Act and the FireProtection Act (Polish Journal of Laws/Dz.U. 2019, item 1593). The amendment of the Atomic LawActs led to the harmonisation of regulations on radioactivity in raw and building materials betweenPoland and the Member States. This article presents the impact of an amendment of the AtomicLaw and of the accompanying normative acts on the studies of the natural radioactivity of raw andconstruction materials, using the example of an analysis of the concentration of natural radioactiveisotopes present in the coal combustion products (CCP), i.e. fly ash, slags and ash-slag mixtures.

Retrospective Analysis of Radiation-Induced Complications of Uveal Melanoma Patients Treated With Brachytherapy in the Era of Anti-VEGF

PURPOSETo associate clinical factors and radiation doses delivered by iodine-125 plaque brachytherapy to visual outcomes and development of radiation-induced ocular complications in patients with uveal melanoma in the era of anti-VEGF injections. DESIGNRetrospective cohort study. METHODSRetrospective chart review was performed for 225 patients treated with iodine-125 brachytherapy for uveal melanoma. The effects of radiation doses (focal doses, average dose to the entire eye, and integral dose) on visual outcomes and development of radiation complications (radiation retinopathy, radiation optic neuropathy, vitreous hemorrhage, and neovascular glaucoma) were analyzed using Multivariate Cox Regression Analysis. RESULTSMedian follow-up was 33.6 months (range, 12 – 105.6). Radiation retinopathy was associated with younger age, tumor distance to optic nerve < 6 mm, and maximum radiation dose to fovea. Radiation optic neuropathy was associated with white race, tumor distance to optic nerve < 6 mm, and integral radiation dose. Vitreous hemorrhage was associated with white race and integral radiation dose. Incidence of neovascular glaucoma was low in our study, with 2 patients (0.9%) developing the complication. Of the 123 patients who developed radiation retinopathy, 82 patients (66.7% of radiation retinopathy patients, 37.3% of total patients) received anti-VEGF injections. CONCLUSIONSOur study found multiple associations between radiation doses and complications as well as visual outcomes on multivariate analysis. Given that the majority of our patients who developed radiation retinopathy received anti-VEGF injections, our study helps illustrate the course and progression of radiation-induced complications in the new era of anti-VEGF.

Anti-tumor Effect of High Doses of Carbon Ions and X-Rays during Irradiation of Ehrlich Ascites Carcinoma Cells Ex Vivo.

The effect of carbon ions (12C) with the energy of 400 MeV/nucleon on the dynamics of induction and growth rate of solid tumors in mice under irradiation of Ehrlich ascites carcinoma cells (EAC) ex vivo at doses of 5-30 Gy relative to the action of equally effective doses of X-ray radiation was studied. The dynamics of tumor induction under the action of 12C and X-rays had a similar character and depended on the dose during 3 months of observation. The value of the latent period, both when irradiating cells with 12C and X-ray, increased with increasing dose, and the interval for tumor induction decreased. The rate of tumor growth after ex vivo irradiation of EAC cells was independent of either dose or type of radiation. The dose at which EAC tumors are not induced within 90 days was 30 Gy for carbon ions and 60 Gy for X-rays. The value of the relative biological effectiveness of carbon ions, calculated from an equally effective dose of 50% probability of tumors, was 2.59.

Радиационно-гигиеническая оценка воздействия негативных природных факторов, а также последствий деятельности ОАО «Гидрометаллургический завод» на население города Лермонтов

The article presents the results of a radiation-hygienic assessment of the contribution to the total effective radiation dose to the population of the radon-hazardous territory (town of Lermontov, Stavropol Region) of the aerosol-unattached fraction of the radon and thoron decay progeny after inhalation of them. Research on this topic was carried out in the Russian Federation for the first time. The article also assesses the possible contribution of the source of anthropogenic radioactive contamination of the surrounding area – the tailings storage facility of JSC «Hydrometallurgical Plant»

The effective radiation dose to immune cells predicts lymphopenia and inferior cancer control in locally advanced NSCLC

PurposeTo explore the association of the effective dose to immune cells (EDIC) with disease control, lymphopenia, and toxicity in patients with non-small cell lung cancer (NSCLC) and identify methods to reduce EDIC. MethodsWe abstracted data from all patients with locally advanced NSCLC treated with chemoradiation with or without consolidative immunotherapy over a ten-year period. Associations between EDIC and progression-free survival (PFS) and overall survival (OS) were modeled with Cox proportional hazards and Kaplan-Meier method. Logistic regression was used to model predictors of lymphopenia and higher EDIC. Analyses were performed with EDIC as a continuous and categorical variable. Lymphopenia was graded per CTCAE v5.0. ResultsOverall, 786 patients were included (228 of which received consolidative immunotherapy); median EDIC was 4.7 Gy. Patients with EDIC < 4.7 Gy had a longer median PFS (15.3 vs. 9.0 months; p < 0.001) and OS (34.2 vs. 22.4 months; p < 0.001). On multivariable modeling, EDIC correlated with inferior PFS (HR 1.08, 95 % CI 1.01–1.14, p = 0.014) and OS (HR 1.10, 95 % CI 1.04–1.18, p = 0.002). EDIC was predictive of grade 4 lymphopenia (OR 1.16, 95 % CI 1.02–1.33, p = 0.026). EDIC ≥ 4.7 Gy was associated with increased grade 2 + pneumonitis (6-month incidence: 26 % vs 20 %, p = 0.04) and unplanned hospitalizations (90-day incidence: 40 % vs 30 %, p = 0.002). Compared to protons, photon therapy was associated with EDIC ≥ 4.7 Gy (OR 5.26, 95 % CI 3.71–7.69, p < 0.001) in multivariable modeling. ConclusionsEDIC is associated with inferior disease outcomes, treatment-related toxicity, and the development of severe lymphopenia. Proton therapy is associated with lower EDIC. Further investigations to limit radiation dose to the immune system appear warranted.

Comparison of screw placement guided by O-arm navigation and ultrasound volume navigation in minimally invasive transforaminal lumbar interbody fusion

To compare the effectiveness of O-arm navigation and ultrasound volume navigation (UVN) in guiding screw placement during minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery. Sixty patients who underwent MIS-TLIF surgery for lumbar disc herniation between June 2022 and June 2023 and met the selection criteria were included in the study. They were randomly assigned to group A (screw placement guided by UVN during MIS-TLIF) or group B (screw placement guided by O-arm navigation during MIS-TLIF), with 30 cases in each group. There was no significant difference in baseline data, including gender, age, body mass index, and surgical segment, between the two groups ( P>0.05). Intraoperative data, including average single screw placement time, total radiation dose, and average single screw effective radiation dose, were recorded and calculated. Postoperatively, X-ray film and CT scans were performed at 10 days to evaluate screw placement accuracy and assess facet joint violation. Pearson correlation and Spearman correlation analyses were used to observe the relationship between the studied parameters (average single screw placement time and screw placement accuracy grading) and BMI. The average single screw placement time in group B was significantly shorter than that in group A, and the total radiation dose of single segment and multi-segment and the average single screw effective radiation dose in group B were significantly higher than those in group A ( P<0.05). There was no significant difference in the total radiation dose between single segment and multiple segments in group B ( P>0.05), while the total radiation dose of multiple segments was significantly higher than that of single segment in group A ( P<0.05). No significant difference was found in the accuracy of screw implantation between the two groups ( P>0.05). In both groups, the grade 1 and grade 2 screws broke through the outer wall of the pedicle, and no screw broke through the inner wall of the pedicle. There was no significant difference in the rate of facet joint violation between the two groups ( P>0.05). In group A, both the average single screw placement time and screw placement accuracy grading were positively correlated with BMI ( r=0.677, P<0.001; r=0.222, P=0.012), while in group B, neither of them was correlated with BMI ( r=0.224, P=0.233; r=0.034, P=0.697). UVN-guided screw placement in MIS-TLIF surgery demonstrates comparable efficiency, visualization, and accuracy to O-arm navigation, while significantly reducing radiation exposure. However, it may be influenced by factors such as obesity, which poses certain limitations.

Estimation of Background Radiation from A Soil Sample from A Barley Farm Area and Malt Factory in East Arsi, Ethiopia

The aim of this work is to estimate the background radiation of a soil sample from the barley farm area and Malt factory in East Arsi, Ethiopia. The technique of gamma-ray spectrometry with a high-purity germanium (HPGe) gamma-ray detector and a PC-based MCA was used. The activity concentration levels due to 40K, 137Cs, 238U, and 232Th were measured within the study area at a depth of 30 cm. The soils of the study region are used as construction material by many farmers. The measured specific activity of those radionuclides was compared with the data reported worldwide. The specific activity of radionuclides was estimated in both study locations. The specific activity 238U of soil samples ranged from 41.0 Bq kg-1 to 30.7 Bq kg-1 in the barley farm, with a mean value of 37.7 Bq kg-1, and for malt ranged from 23.8 Bq kg-1 to 40.6 Bq kg-1, with a mean value of 32.5 Bq kg-1. The specific activity of 232Th in soil samples ranged from 89.9 Bq kg-1 to 156.0 Bq kg-1, with a mean value of 118.6 Bq kg-1, whereas for the Malt factory ranged from 121.0 Bq kg-1 to 128.0 Bq kg-1, with a mean value of 123.7 Bq kg-1. In barley soil samples, the specific activity of 40K ranged from 401.0 Bq kg-1 to 530.0 Bq kg-1 with a mean value at the Malt plant ranged from 518 Bq kg-1 to 598.0 Bq kg-1, with a mean value of 553.6 Bq kg-1. Similarly, the specific activity of 137Cs was determined in both the barley farm and the malt Factory. In barley farm soil samples, it ranged from 3.3 ±0.6 Bq kg-1 to 5.34±0.6 Bq kg-1, and with a mean value of 4.3 Bq kg-1 whereas, in the Malt factory it varied from 3.1 ±0.7 Bq kg-1 to 5.3 ±0.7 Bq kg-1, and with a mean value of 4.5 Bq kg-1. The absorbed dose rate within the barley farm ranged from 24.6 ±2.9 nGyh-1 to 34.1 ±2.9 nGy h-1, and with a mean value of 30.6 nGyh-1, whereas, in the Malt factory, it varied from 31.3 ±1.3 nGy h-1 to 35.5 ±1.3 nGyh-1, and with a mean value of 33.5 nGy h-1. The annual effective radiation dose for BSS and MFSS was calculated to be 37.6 mSv y-1and 41.1mSv y-1. This study revealed that this region lies within a medium radiation background when compared with the world's average. The marginal value of dose is higher within the Malt factory area because of fertilizer consumption for cultivation. Since these estimated background and radiological impact factors are below the recommended values, it seems that there is no potential radiological health hazard related to the soils from both BSS and MFSS in Arsi Asella, Oromia, Ethiopia.

Comparison of the Effective Radiation Dose in the Region of the Facial Skull Between Multidetector CT, Dental Conebeam CT and Intraoperative 3D C-Arms

Study Design Experimental single-centre study of X-ray absorption using a phantom skull. Objective This experimental study aimed to compare the radiation doses of different 3D imaging devices used in maxillofacial surgery, including one Multidetector CT (MDCT), two Conebeam CT (CBCT) and four intraoperative 3D C-arms. Methods Thermoluminescent dosimeters (TLD) were used to determine the absorbed radiation in an Alderson-Rando phantom skull. The phantom skull was positioned in the before mentioned seven devices and a defined 3D facial skull image was acquired. Subsequently, the TLD’S were read out and the effective doses (ED) and the organ doses (OD) were calculated and compared. Results OD varied significantly between tissues as well as between the 3D X-ray devices. The OD of the 3D C-arms were significantly lower than those of all other devices. The OD of the CT, especially in the standard setting, was the highest. Only by special adjustments of the scan protocol regarding CMF requirements for traumatology, the MDCT could achieve almost equivalent doses as the two tested CBCT-scanners. The calculated effective doses were also lowest for the 3D C-arm devices (11.2 to 129.9 μSv). The ED of the MDCT were significant higher (284.52–844.97 μSv) than in all other devices. The ED of the CBCTs (173.7–184.9) were lower than for MDCT but still higher than those of the 3D C-arms. Conclusions Intraoperative imaging using 3D C-arm devices is an effective method to verify reduction results in maxillofacial surgery intraoperatively with significantly lower ED than postoperatively CBCT and MDCT imaging.

Dose escalation for stereotactic arrhythmia radioablation of recurrent ventricular tachyarrhythmia - a phase II clinical trial

BackgroundStereotactic arrhythmia radioablation (STAR) is delivered with a planning target volume (PTV) prescription dose of 25 Gy, mostly to the surrounding 75–85% isodose line. This means that the average and maximum dose received by the target is less than 35 Gy, which is the minimum threshold required to create a homogenous transmural fibrosis. Similar to catheter ablation, the primary objective of STAR should be transmural fibrosis to prevent heterogenous intracardiac conduction velocities and the occurrence of sustained ventricular arrhythmias (sVA) caused by reentry. We hypothesize that the current dose prescription used in STAR is inadequate for the long-term prevention of sVA and that a significant increase in dose is necessary to induce transmural scar formation.ObjectiveA single arm, multi-center, phase II, dose escalation prospective clinical trial employing the i3 + 3 design is being conducted to examine the safety of a radiation dose-escalation strategy aimed at inducing transmural scar formation. The ultimate objective of this trial is to decrease the likelihood of sVA recurrence in patients at risk.MethodsPatients with ischemic or non-ischemic cardiomyopathy and recurrent sVA, with an ICD and history of ≥ 1 catheter ablation for sVA will be included. This is a prospective, multicenter, one-arm, dose-escalation trial utilizing the i3 + 3 design, a modified 3 + 3 specifically created to overcome limitations in traditional dose-finding studies. A total of 15 patients will be recruited. The trial aims to escalate the ITV dose from 27.0 Gy to an ITV prescription dose-equivalent level of maximum 35.1 Gy by keeping the PTV prescription dose constant at 25 Gy while increasing the dose to the target (i.e. the VT substrate without PTV margin) by step-wise reduction of the prescribing isodose line (85% down to 65%). The primary outcome of this trial is safety measured by registered radiation associated adverse events (AE) up to 90 days after study intervention including radiation associated serious adverse events graded as at least 4 or 5 according to CTCAE v5, radiation pneumonitis or pericarditis requiring hospitalization and decrease in LVEF ≥ 10% as assessed by echocardiography or cardiac MRI at 90 days after STAR. The sample size was determined assuming an acceptable primary outcome event rate of 20%. Secondary outcomes include sVA burden at 6 months after STAR, time to first sVA recurrence, reduction in appropriate ICD therapies, the need for escalation of antiarrhythmic drugs, non-radiation associated safety and patient reported outcome measures such as SF-36 and EQ5D.DiscussionDEFT-STAR is an innovative prospective phase II trial that aims to evaluate the optimal radiation dose for STAR in patients with therapy-refractory sVA. The trial has obtained IRB approval and focuses on determining the safe and effective radiation dose to be employed in the STAR procedure.Trial registrationNCT05594368.

Space radiation environment adaptability of the domestic 5056 high-performance aluminum honeycomb

In order to investigate the influence of space radiation environment on the performance of domestic 5056 high-performance aluminum honeycomb core, the effects of different irradiation effects and different radiation doses on the nodal strength and mechanical properties of domestic 5056 high-performance aluminum honeycomb core were studied through space radiation environmental tests and mechanical property tests such as high-energy electron irradiation, γ-ray irradiation, ultraviolet irradiation, hot and cold shock test, vacuum volatilization test. The results show that under multiple environmental conditions such as high-energy electron irradiation γ-ray irradiation, ultraviolet irradiation, and hot and cold shock environment, the domestic high-performance aluminum honeycomb core shows excellent adaptability to the irradiation environment and can be used for a long time in the extravehicular environment. However, when the radiation dose is greater than 2 × 109rad, the strength of honeycomb core nodes decreased significantly. The vacuum volatilization test results sindicate that the material meets the gas requirements of aerospace raw materials and has extremely low vacuum pollution characteristics.

Optimizing Radiation Dose Using Ctdi Value Analysis and Image Quality in the Thorax Low Dose CT Scan (LDCT) Technique with Reduced Dose Variations Using Idose Software

Radiation exposure to patients with higher cumulative effective doses on thorax CT scanning is very detrimental for cancer patients undergoing follow-up and raises the level of concern about the harmful effects of radiation doses received by patients. Reducing the tube voltage will reduce the radiation dose and image quality. To maintain good image quality, the iDose strength level is set. iDose is able to reduce radiation dose and improve image quality by maintaining low noise. Analyze the optimization of radiation dose and image quality in the thorax Low Dose CT Scan (LDCT) examination protocol with tube voltage settings and variations in the use of iDose software. This type of research is True-Experimental research with a Posttest-Only Control Design. The object used is a water phantom with tube voltage settings of 80 kVp, 100 kVp and 120 kVp and the use of iDoe 3 -5. Assessment includes radiation dose, noise, SNR and NPS. After getting optimal results from setting the tube voltage and iDose strength level, these results were applied to a Thorax CT Scan examination in patients, and a subjective assessment of image quality was carried out. Reducing the tube voltage (kVp) from 120 kV to 80 kV was able to reduce the radiation dose by 69.8%, and reducing the tube voltage from 120 kV to 100 kV in the Thorax CT Scan protocol was able to reduce the radiation dose by 34.2 %. There is an influence of setting the tube voltage and setting the iDose strength level on the radiation dose and image quality of the Low Dose CT Scan of the Thorax. Setting tube voltage and high iDose strength levels can improve image quality in CT scans, characterized by decreasing noise and NPS values and increasing SNR values. Tube voltage settings and iDose level settings affect the radiation dose and image quality. The use of a tube voltage of 80 kVp and strength level iDose 5 is able to provide optimal radiation dose and image quality on Thorax Low Dose CT Scan.