Radiation Dose Values Research Articles

Combinations of Digital Breast Tomosynthesis and Full-field Digital Mammography for Different Density Types of Breasts.

The combination of FFDM and DBT can significantly improve the diagnostic efficiency of breast cancer, but with the increase of breast radiation absorbed dose. To compare and analyze the radiation dose and diagnostic performance of different mammography positions combinations of digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) for different density types of breasts. This retrospective study involved 1,195 patients who underwent simultaneous breast DBT and FFDM. The mammography combinations were Group A, FFDM(CC+MLO); Group B, FDM(CC)+DBT(MLO); Group C, FFDM(MLO)+DBT(CC); Group D, DBT(CC+MLO); and Group E, FFDM(CC+MLO)+DBT(CC+MLO). An intergroup comparative analysis of radiation dose and diagnostic performance of different combinations of mammography positions for different breast density types was performed using the pathologic and 24-month follow-up results as the diagnostic basis. Overall, 2,403 mammograms indicated 477 cases of non-dense breast tissues and 1,926 cases of dense breast tissues. Differences in the mean radiation dose for each non-dense and dense breast group were statistically significant. The areas under the diagnostic receiver operating characteristic (ROC) curves for the non-dense breast group were not statistically significant. In the dense breast group, the z-values were 1.623 (p = 0.105) and 1.724 (p = 0.085) for the area under the ROC curve in Group C compared with Groups D and E, respectively, and 0.724 (p = 0.469) when comparing Group D with Group E. The differences between the remaining groups were statistically significant. Group A had the lowest radiation dose and no significant difference in diagnostic performance compared with the other non-dense breast groups. Group C had high diagnostic performance in the dense breast group considering the low radiation dose.

Intraoperative fluoroscopic radiation in orthopedic trauma: correlation with surgery type and surgeon experience.

While fluoroscopy is widely used in orthopedic trauma surgeries, it is associated with harmful effects and should, therefore, be minimized. However, reference values for these surgeries have not been defined, and it is not known how surgeon experience affects these factors. The aims of this study were to analyze the radiation emitted and exposure time for common orthopedic trauma surgeries and to assess whether they are affected by surgeon experience. Data from 1842 trauma orthopedic procedures were retrospectively analyzed. A total of 1421 procedures were included in the analysis. Radiation dose and time were collected to identify reference values for each surgery and compared for when the lead surgeon was a young resident, a senior resident, or a specialist. The most performed surgeries requiring fluoroscopy were proximal femur short intramedullary nailing (n = 401), ankle open reduction and internal fixation (ORIF) (n = 141), distal radius ORIF (n = 125), and proximal femur dynamic hip screw (DHS) (n = 114). Surgeries using higher radiation dose were proximal femur long intramedullary nailing (mean dose area [DAP]): 1361.35 mGycm2), proximal femur DHS (1094.81 mGycm2), and proximal femur short intramedullary nailing (891.41 mGycm2). Surgeries requiring longer radiation time were proximal humerus and/or humeral shaft intramedullary nailing (02 mm:20 ss), proximal femur long intramedullary nailing (02 mm:04 ss), and tibial shaft/distal tibia intramedullary nailing (01 mm:49 ss). Senior residents required shorter radiation time when performing short intramedullary nailing of the proximal femur than young residents. Specialists required more radiation dose than residents when performing tibial nailing and tibial plateau ORIF and required longer radiation time than young residents when performing tibial nailing. This study presents mean values of radiation dose and time for common orthopedic trauma surgeries. Orthopedic surgeon experience influences radiation dose and time values. Contrary to expected, less experience is associated with lower values in some of the cases analyzed.

Radiation Exposure and Frequency of Dental, Bitewing and Occlusal Radiographs in Children and Adolescents.

Dental radiographs are valuable diagnostic aids for oral healthcare, but exposure to ionizing radiation carries health risks, especially in children due to their high radio-sensitivity. Valid reference values for intraoral radiographs in children and adolescents are still missing. This study aimed to investigate the radiation dose values and underlying justifications of dental, bitewing and occlusal X-rays in children and adolescents. Data from routinely executed intraoral radiographs between 2002 and 2020 with conventional and digital tube-heads were extracted from the Radiology Information System. The effective exposure was calculated from technical parameters and statistical tests performed. A total number of 4455 intraoral (3128 dental, 903 bitewing and 424 occlusal) radiographs were investigated. For dental and bitewing radiographs, the dose area product (DAP) was 2.57 cGy × cm2 and the effective dose (ED) 0.77 µSv. For occlusal radiographs, the DAP was 7.43 cGy × cm2 and the ED 2.22 µSv. Overall, 70.2% of all intraoral radiographs were dental, 20.3% bitewing and 9.5% occlusal radiographs. The most frequent indication for intraoral radiographs was trauma (28.7%), followed by caries (22.7%) and apical diagnostics (22.7%). Moreover, 59.7% of all intraoral radiographs were taken in boys, especially for trauma (66.5%) and endodontics (67.2%) (p ≤ 0.00). Girls were significantly more frequently X-rayed for caries diagnostics than boys (28.1% vs. 19.1%, p ≤ 0.00). The average ED of 0.77 µSv for intraoral dental and bitewing radiographs in this study was within the range of other reported values. The technical parameters of the X-ray devices were found at the lowest recommended levels to best limit the radiation exposure and to assure acceptable diagnostic efficacy. Intraoral radiographs were performed predominantly for trauma, caries and apical diagnostics-reflecting general recommendations for the use of X-rays in children. For improved quality assurance and radiation protection, further studies are necessary to determine the meaningful dose reference level (DRL) for children.

THE DEVELOPMENT OF GAMMA RADIATION DOSIMETERS REAL-TIME NETWORK-BASED SENSOR WIRELESS IEEE 802.15.4 PROTOCOL

Several studies have been carried out on the development of real-time gamma radiation dosimeter based on the wireless sensor network (WSN) protocol IEEE 802.15.4. WSN technology can be adopted to develop a gamma radiation dose monitoring system on a large scale due to its real-time, centralized, efficient, and relatively low-cost attributes. This study aims to develop a personal radiation dosimeter that can collect data from the measurement results of several sensor nodes or multi-sensors. The measurement results of radiation dose values from many radiation workers are sent to a coordinator node consisting of the Xbee module and Arduino as a microcontroller. The system test is compared with a calibrated dosimeter reading and is expected to be one of the instruments for determining radiation dose in real-time. It can also reduce the risk of receiving a radiation dose that exceeds the threshold allowed by the ionizing control agency and a program in radiation protection. Changes in the intensity of radiation emitted by Cs-137 (gamma radiation) are carried out by varying each detector's distance to the source, which indirectly varies the value of the dose rate received by the detector. This relationship is shown from the value of R2 = 0.99, which indicates a strong correlation between changes in the dose given to the detector's response being developed. The system built is efficient, inexpensive, and collecting radiation exposure data can monitor radiation exposure received by workers in real-time. This technique can help speed up reporting of radiation exposure received by radiation workers.

Gamma radiation dose rate distribution in the Anand, Bharuch, Vadodara, and Narmada districts of Gujarat, India.

Radiation is present everywhere in the earth, and human beings are continuously exposed to gamma radiation. The health consequences of environmental radiation exposure are a serious societal issue. The purpose of this study was to analyse outdoor radiation in four districts of Gujarat, India: Anand, Bharuch, Narmada, and Vadodara duringsummer and winter seasons. This study illustrated the influence of lithology of areas on gamma radiation dose values. Summer and winter seasons are the primary factors that alter the causes directly or indirectly; therefore, the influence of season fluctuation on radiation dose rate was investigated. The annual dose rate and mean gamma radiation dose rate values from four districts were found to be greater than the global population weight average value. The mean value of gamma radiation dose rate from 439 locations in thesummer and winterseasons was 136.23 nSv/h and 141.58 nSv/h, respectively. According to a paired differences sample study, the significance value between outdoor gamma dose rate insummer and winterseasons was 0.05 indicating that seasons have a significant impact on gamma radiation dose rate. The impact of various types of lithology on gamma radiation dose was studied in all 439 places, and the statistical analysis revealed that there was no significant association between lithology and gamma radiation dose rate in the summer season, but a relationship between lithology and gamma dose rate was observed in the winter season.

Radiation dose estimates based on Monte Carlo simulation for spiral breast computed tomography imaging in a large cohort of patients.

Spiral breast computed tomography (BCT) equipped with a photon-counting detector (PCD) is a new radiological modality allowing for the compression-free acquisition of high-resolution 3-D datasets of the breast. Optimized dose exposu04170/re setups according to breast size were previously proposed but could not effectively be applied in a clinical environment due to ambiguity in measuring breast size. This study aims to report the standard radiation dose values in a large cohort of patients examined with BCT, and to provide a mathematical model to estimate radiation dose based on morphological features of the breast. This retrospective study was conducted on 1657 BCT examinations acquired between 2018 and 2021 from 829 participants (57±10 years, all female). Applying a dedicated breast tissue segmentation algorithm and Monte Carlo (MC) simulation, mean absorbed dose (MAD), mean glandular dose (MGD), mean skin dose (MSD), maximum glandular dose (maxGD), and maximum skin dose (maxSD) were calculated and related to morphological features such as breast volume, effective diameter, breast length, skin volume, and glandularity. Effective dose (ED) was calculated by applying the corresponding beam and tissue weighting factors, 1Sv/Gy and 0.12 per breast. Relevant morphological features predicting dose values were identified based on the Spearman's rank correlation coefficient. Exponential or bi-exponential models predicting the dose values as a function of morphological features were fitted by using a non-linear least squares (LS) method. The models were validated by assessing R2 and residual standard error (RSE). The most relevant morphological features for radiation dose estimation were the breast volume (correlation coefficient: -0.8), diameter (-0.7), and length (-0.6). The glandularity presented a weak-positive correlation (0.4) with MGD and maxGD due to the inhomogeneous distribution of the glandularity and absorbed dose in the 3-D breast volume. The standard MGDs were calculated to be 7.3±0.7, 6.5±0.3, and 5.9±0.3 mGy, MADs to 7.6±0.8, 6.8±0.3, and 6.2±0.3 mGy, maxSDs to 19.9±1.6, 19.5±0.5, and 18.9±0.5 mGy, and EDs to 0.88±0.08, 0.78±0.04, and 0.72±0.04 mSv for small, medium, and large breasts with average breast lengths of 5.9±1.6, 8.7±1.3, and 12.2±2.0cm, respectively. The estimated glandularity - 23.1±16.9, 12.5±11.4, and 6.9±7.3% from small to large breasts. The mathematical models were able to estimate the MAD, MGD, MSD, and maxSD as a function of each morphological feature with only upto 0.5 mGy RSE. We presented the typical morphological features and standard dose values according to the breast size acquired from a large patient cohort. We established radiation dose estimation models allowing accurate estimation of dose values including MGD with an acceptable RSE based on each of the easily measured morphological features of the breast. Clinicians could use the breast length to operate as a dosimetric alert of the scanner prior to a BCT scan. Radiation exposure for BCT was lower than diagnostic mammography (MG) and cone-beam breast CT (BCT).

DRIVERS OF HYPERFERREMIA IN CHILDREN LIVING ON RADIOLOGICALLY CONTAMINATED TERRITORIES AFTER THE CHNPP ACCIDENT IN UKRAINE.

assessment of clinical-hematological and metabolic-biochemical parameters of the of bone tissue and hormonal regulation depending on the serum iron content and radiation dose values in children living on radiologically contaminated territories after the ChNPP accident in Ukraine. Children (n = 271) living on radiologically contaminated territories (RCT) of Ukraine were involved in the study. Three study groups were formed according to the serum iron level (SIL), namely group I with SIL 10.0-22.0 μmol/l (n = 92), group II with SIL 23.0-34.0 μmol/l (n = 144), and group III with SIL above 35.0 μmol/l (n = 35). Diseases in the family tree, bodyweight at birth, complaints on osalgia, bone fractures, jaw anomalies, dental caries, and obesity were accounted. Morphometric parameters of erythrocytes and hemogram elements were analyzed. Creatinine, alkaline phosphatase, calcium, total protein, iron, cholesterol, bilirubin, and transaminases were assayed in blood serum. The urine content of the 19 free amino acids, serum content of the free thyroxine (FT4), pituitary thyroid-stimulating hormone (TSH), and cortisol were assayed both with bone tissue density. Individual radiation doses were calculated. In 12.9 % of cases the SIL was > 35.0 μmol/l. Relatives with endocrine diseases were often present in the family tree of children with SIL > 23.0 μmol/l. There were increased urine content of the free amino acids (p < 0.05) and signs of protein degradation under high SIL. Contents of amino acids involved in collagen synthesis and antioxidant status (alanine, serine, glutamine, aspartic acid) and iron metabolism (arginine, leucine) were assayed at the highest levels (p < 0.05). Urinary levels of valine, lysine, and methionine, which are associated with iron metabolism, were decreased (p < 0.05). An inverse correlation (rs = -0.58; p < 0.01) was established between the serum TSH and cortisol levels regardless of the SIL. Serum TSH level directly correlated with urine content of amino acids involved in collagen synthesis. An inverse correlation (rs = -0.55; p < 0.001) was established between the serum TSH level and urine content of tyrosine that is essential for the thyroid hormone (triiodothyronine and thyroxine) synthesis.Cortisol was found having a negative effect on protein synthesis. Inverse correlation was established between the serum cortisol level and urine content of the free amino acids essential for collagen synthesis. There was no dependence of the average radiation dose values on the SIL. An inverse correlation was determined between the patient's radiation dose and SIL > 35.0 μmol/l (rs = -0.29; p < 0.05). The increased SIL in children living on RCT may occur due to both a genetic predisposition and the acquired factors driving protein and mineral metabolism of bone and their hormonal regulation.

GEANT4 simulation of parasitic X-ray radiation for backward wave oscillator SINUS-350

Parasitic X-ray radiation for the backward wave oscillator SINUS-350 is investigated. Using the GEANT4 simulation toolkit we have made a model of this oscillator which allows calculating the radiation dose and energy spectrum around the accelerator. The results of these calculations have been compared with measurements for 2 s accelerator operation time. The obtained values of radiation doses at a distance of 1–2 m from the generator are in the range (10–300) μSv. These values significantly exceed the maximum permissible amount because the personal maximum permissible dose per year is 1000 μSv. Therefore, the question of how to achieve a significant reduction is very important. We have also calculated the energy spectrum of the X-rays for different places. The largest part of the spectrum is in the range 50–350 keV.

Optimisasi dengan Audit Dosis Radiasi pada Pemeriksaan Thorak Proyeksi AP Pasien Dewasa

Optimization is one of the radiation protection efforts by giving radiation doses to patients as low as possible without reducing the quality of clinical images or what is often referred to as ALARA (As Low as Reasonably Achievable). A Diagnostic Reference Level (DRL) is an investigative indicator to optimize radiation protection for diagnostic and interventional radiology patients. The typical radiation dose value in AP thoracic examination patients at Gading Pluit Hospital is higher than the Indonesian DRL (I-DRL) value, so it is necessary to optimize the dose. Optimization of radiation dose aims to protect patients by evaluating exposure factors without compromising the quality of clinical images. AP chest image acquisition was performed using clinical exposure factors and their variations on the general radiographic X-Ray Listem REX 525-R. Evaluation of dose and image quality was carried out by a reading doctor/radiologist using a blind test. Optimizing results show that a lower exposure factor can reduce the radiation dose in AP thoracic examination of adult patients without affecting image quality. Exposure factor 80 kVp; 150 mA; 3.75 mAs is recommended to replace the exposure factor used before optimization, namely 80 kVp; 200 mA; 7 mAs. Keywords: optimization, DRL, radiation protection.

Analisis Dosis Radiasi pada Pemeriksaan CT Scan Kepala Menggunakan Metode Sekuensial dan Helical

This study aims to analyze the radiation dose in the Computed Tomography (CT) Scan of the Head using the sequential and helical scan methods at the Radiology Installation of Fatmawati General Hospital. This research is quantitative with an observation approach. Data were collected at the Fatmawati General Hospital Radiology Installation in October 2021. The data was taken from a CT Scan Head sample from August to October 2021, so 18 patients were obtained using the sequential scan method and 18 patients using the helical scan method. The results showed that the sequential scan got an average CTDIvol value of 29.5161 mGy and an average DLP value of 546.3867 mGy.cm. The helical scan method got an average CTDIvol value of 49.9456 mGy and an average DLP value of 981.8178 mGy.cm. Statistical analysis showed that the value of the Wilcoxon sign rank test on the sequential and helical scan methods was p value = 0.002. That means there is a difference in the average radiation dose value in the sequential and helical scan methods. There are differences in CTDIvol and DLP values in the sequential and helical scan methods. The dose obtained using the sequential scan method is lower than that of helical. Keywords: CT Scan Head, Sequential, Helical, CTDIvol

Diagnostic Validity and Reliability of Low-Dose Prospective ECG-Triggering Cardiac CT in Preoperative Assessment of Complex Congenital Heart Diseases (CHDs).

For the precise preoperative evaluation of complex congenital heart diseases (CHDs) with reduced radiation dose exposure, we assessed the diagnostic validity and reliability of low-dose prospective ECG-gated cardiac CT (CCT). Forty-two individuals with complex CHDs who underwent preoperative CCT as part of a prospective study were included. Each CCT image was examined independently by two radiologists. The primary reference for assessing the diagnostic validity of the CCT was the post-operative data. Infants and neonates were the most common age group suffering from complex CHDs. The mean volume of the CT dose index was 1.44 ± 0.47 mGy, the mean value of the dose-length product was 14.13 ± 5.4 mGy*cm, and the mean value of the effective radiation dose was 0.58 ± 0.13 mSv. The sensitivity, specificity, PPV, NPV, and accuracy of the low-dose prospective ECG-gated CCT for identifying complex CHDs were 95.6%, 98%, 97%, 97%, and 97% for reader 1 and 92.6%, 97%, 95.5%, 95.1%, and 95.2% for reader 2, respectively. The overall inter-reader agreement for interpreting the cardiac CCTs was good (κ = 0.74). According to the results of our investigation, low-dose prospective ECG-gated CCT is a useful and trustworthy method for assessing coronary arteries and making a precise preoperative diagnosis of complex CHDs.

Factors Affecting Permanent Sensorineural Hearing Loss and Bone Conduction in Patients After Receiving Radiotherapy to the Head and Neck Region.

This study aimed to investigate the factors affecting permanent sensorineural hearing loss (SNHL) and causing changes in bone conduction (BC) thresholds over time in patients after receiving radiotherapy (RT) or chemoradiotherapy (CRT) to the head and neck region. A total of 63 patients with irradiated HNC that were admitted to the Radiation Oncology Department between 2011 and 2018 were included in the study. All patients were assessed with pure tone audiometry at eight different time points (first before RT and last five years after completion of RT). A chi-square test was used to analyze the variables that affected permanent SNHL occurrence. Repeated measure analysis of variance was conducted to investigate the factors affecting change in the BC threshold at pure-tone average (0.5-2 kHz) and the air conduction (AC) threshold at 4 and 6 kHz frequencies over time. Median follow-up was 52 months (range, 12-110 months). SNHL was found in 18 (14%) of the 126 ears. According to the receiver operating characteristic analysis, the cut-off values of cochlear Dmean and Dmax radiation doses were 40 Gy [p=0.017, area under the curve (AUC): 0.676] and 45 Gy (p=0.008, AUC: 0.695). Dmean (≤40 Gy vs. >40 Gy) and Dmax (≤45 Gy vs. >45 Gy) cochlear doses and age (≤40 vs. >40 years) were determined as factors affecting SNHL in the chi-square test. Repeated measures showed that BC thresholds between 0.5-2 kHz and AC thresholds at 4 and 6 kHz increased over time. Age (≤40 vs. >40 years), treatment of head and neck cancer (RT vs. CRT), cisplatin use, and Dmean (≤40 Gy vs. >40 Gy) and Dmax cochlear dose (≤45 Gy vs. >45 Gy) were important factors affecting the course of BC threshold over time. Dmean and Dmax cochlear doses and age were found to be associated with permanent SNHL. Conduction thresholds worsened over time at all frequencies, and this trend was affected by cochlear doses, age, CRT, and cisplatin use.

ESTIMASI NILAI DOSIS PADA PEMERIKSAAN CT SCAN KEPALA DEWASA BERDASARKAN NILAI CTDIvol DAN DLP

ABSTRACT&#x0D; &#x0D; Background: Estimating the exact dose in CT Scan patients can be done by referring to an optimization index called DRL (Diagnostic Reference Level). Currently, the DRL for CT-Scans is expressed in CTDIvol (Computed Tomography Dose Index Volume) and DLP (Dose Length Product). The purpose of this study was to analyze the distribution of radiation dose values ​​on a CT scan of the adult head based on the CTDIvol and DLP values ​​referring to the IDRL reference from BAPETEN.&#x0D; Methods: This research is descriptive quantitative research with an observational approach. The Samples in this study were all patients who underwent Non-Contrast Head CT-Scan examinations at the radiology installation of Prof.Dr.I.G.N.G. Ngoerah Hospital, Denpasar for the period January-June 2022. Analysis of Results The estimation of radiation dose values ​​on CT Scan examinations of the adult head was based on the recapitulation of the distribution of CTDIvol and DLP values ​​obtained then compared with the IDRL 2021 values.&#x0D; Results: CTDIvol values ​​on non-Contrast head CT examination for all patients have varied values ​​with the lowest value of 23.28 mGy, the highest value of 62.7 mGy, an average of 47.58 mGy, and the 3rd quartile value of CTDIvol is 49.84 mGy. With the 75th percentile CTDIvol value of 49.84 mGy while the DLP value on the Head CT Examination varied in each patient with the lowest DLP value of 700.12 mGy*cm and the highest DLP value of 1597.19 mGy*cm and an average value of 1597.19 mGy*cm. DLP is 1057.95 mGy*Cm and the 3rd quartile value of DLP is 1133 mGy*cm.&#x0D; Conclusion: The CTDIvol and DLP values ​​for Non-Contrast Adult Head CT Scan examination at Prof.Dr.I.G.N.G. Ngoerah Hospital Denpasar are still below the reference from BAPETEN in IDRL 2021.

Comparison of image quality between a novel mobile CT scanner and current generation stationary CT scanners

PurposePoint-of-care imaging with mobile CT scanners offers several advantages, provided that the image quality is satisfactory. Our aim was to compare image quality of a novel mobile CT to stationary scanners for patients in a neurosurgical intensive care unit (ICU).MethodsFrom November 2020 to April 2021, all patients above 18 years of age examined by a mobile CT scanner at a neurosurgical ICU were included if they also had a stationary head CT examination during the same hospitalization. Quantitative image quality parameters included attenuation and noise in six predefined regions of interest, as well as contrast-to-noise ratio between gray and white matter. Subjective image quality was rated on a 4-garde scale, by four radiologists blinded to scanner parameters.ResultsFifty patients were included in the final study population. Radiation dose and image attenuation values were similar for mobCT and stationary CTs. There was a small statistically significant difference in subjective quality rating between mobCT and stationary CT images. Two radiologists favored the stationary CT images, one was neutral, and one favored mobCT images. For overall image quality, 14% of mobCT images were rated grade 1 (poor image quality) compared to 8% for stationary CT images.ConclusionPoint-of-care brain CT imaging was successfully performed on clinical neurosurgical ICU patients with small reduction in image quality, predominantly affecting the posterior fossa, compared to high-end stationary CT scanners.

Gaussian Processes for radiation dose prediction in nuclear power plant reactors

In nuclear power plants, there are high-exposure jobs, like refuelling and maintenance, that require getting close to the reactor between operation cycles. Therefore, reducing radiation dose during these periods is of paramount importance regarding safety regulations. While there are some manipulable variables, like levels of certain corrosion products, that can influence the final level of radiation dose, there is no way to determine it in a principled way. In this work, we propose to use Machine Learning to predict the radiation dose in the reactor at the cycle end based on information available during the cycle operation. In particular, we use a Gaussian Process to model the relation between cobalt radioisotopes (a certain kind of corrosion product) and radiation dose levels. Gaussian Processes acknowledge the uncertainty on their predictions, a desirable property considering the high-risk nature of the present application. We report experiments on real data gathered from five different power plants in Spain. Results show that these models can be used to estimate the future values of radiation dose in a data-driven way. Moreover, there are tools based on these models currently in development for their application in power plants.

Statistical analysis of factors contributing to the formation of the external radiation dose

Objective . To determine factors contributing to the formation of the external radiation dose in individuals living in radionuclide-contaminated areas. Materials and methods . 25,503 residents from 289 settlements of the Gomel region were examined by the method of thermoluminescent dosimetry. Results . Some statistically significant differences between the doses in men and women were revealed. The study of age and sex groups found that the values of the external radiation dose in young men were 11% as high as those in women of the same age group. The values of the external radiation dose in elderly men were almost 10% as high as those in women of this group. The analysis of the type of activity of all the examined individuals has showed a large variation of external exposure dose values: on average, the external radiation dose is 32% as high in individuals who due to the nature of their practical activities stay outdoors for a long time as that in individuals who work in shielded premises and buildings. Conclusion . The factors contributing to the formation of the external exposure dose in individuals living in radionuclide-contaminated areas have been identified.

A model for prognosis of influence of radiation dose on value of charge carrier mobility: an analytical approach for analysis of the introduced model

In this paper, we analyzed the dependence of charge carriers mobility on value of radiation dose during ion implantation. Based on the considered model, we determine conditions to decrease radiation damage in the irradiated materials. Also we introduce an analytical approach to analyze mass transfer in the irradiated materials. The approach gives a possibility to take into account nonlinearity of the considered process, as well as changes of parameters of the considered process in space and time at one time.

Clinical Question Influence on Radiation Dose of Cardiac CT Scan in Children.

Background: To assess the impact of different clinical questions on radiation doses acquired during cardiac computed tomography in children. Methods: A total of 116 children who underwent cardiac CT on a third-generation dual-source CT scanner were included. The clinical questions were divided into three main categories: the extent of scanning in the z-axis, coronary artery assessment and cardiac function assessment. Radiation dose values represented as a dose-length product (DLP) in mGy*cm were recorded from the CT scanner protocols. Results: There were significantly higher doses in cases with cardiac function assessment (median DLP 348 versus 59 mGy*cm, p < 0.01) and in cases with coronary artery assessment (median DLP 133 versus 71 mGy*cm, p < 0.01). Conclusion: The most important factor was the assessment of cardiac function, where the median radiation dose was 4.3× higher in patients with a request for cardiac function assessment. We strongly recommend that clinical requests for cardiac CT should be carefully considered in the paediatric population.

Investigating Background Ionizing Radiation in some selected locations in Agbor Metropolis.

The level of background indoor and outdoor ionizing radiation doses were measured in 15 different locations in Agbor, Delta State of Nigeria, with the aid of an inspector alert nuclear radiation meter. The recorded indoor ionizing radiation ranged from 0.114 µSv/hr to 0.271 µSv/hr with a mean value of 0.189 ± 0.04 µSv/hr. DDPA peaked at 0.271± 0.08 µSv/hr. Outdoor radiation levels on the other hand ranged from 0.110 µSv/hr to 0.256 µSv/hr with a mean value of 1.80 ± 0.05 µSv/hr. Model laboratory recorded the highest outdoor radiation dose value of 0.256 ± 0.03 µSv/hr. These values were all below the allowable limit set by UNSCEAR. Furthermore, the ambient BIR levels obtained in all the locations studied were equally below the ambient BIR allowable limit of 0.13 mR/h. The calculated annual effective dose rates value E0 (indoor) for the locations studied were variable, while the annual effective dose rate E1 (outdoor) obtained for all the locations studied were less than the standard limit of 1.00 mSv/yr, making the latter locations to be radiological safe for human habitation without constituting notable health hazards.

ESTIMASI DOSIS RADIASI YANG DITERIMA PASIEN PADA PEMERIKSAAN THORAX PA

Background : Radiation dose received by patients during medical radiology examination varied among practices. This is due to difference in techniques, filter, and equipment used during examinations. This study aims to determine the value of facilities Diagnostic Reference Level (fDRL) in Radiology hospitals district Buleleng and comparison of the 75th percentile value of radiation dose received by adult Thorax PA patients with the standards established by BAPETEN.&#x0D; Methods: This type of research uses a quantitative method with a survey conducted at the Radiology Installation of Buleleng Regency Hospital in February 2020. The population of this study was all patients who underwent radiographic examination of Thorax PA adults (over 15 years). While the sample in this study was 30 patients with Thorax PA radiography examination adult (over 15 years). Absorbent dose measurement data is carried out directly with a digital dosimeter measuring device and then processed using SPSS.&#x0D; Results and Conclusion: The results of this study obtained the value of facilities Diagnostic Reference Level for examination of adult PA Thorax in Radiology Installation of Buleleng Regency Hospital is 0.0275 mGy and the percentile value of 75 absorbent doses received by PA thorax patients adult in Radiology Installation of Buleleng Regency Regional Hospital is 0.0275 mGy where the dose Radiation absorption received by PA thorax patients has met the standards set by BAPETEN in the Indonesian Diagnostic Reference Level (IDRL) 2019 radiation absorbed dose received by adult thorax PA patients, which is 0.4 mGy.