Dose Reference Levels Research Articles

Risk assessment of 226Ra and 222Rn from the drinking water in the Jalandhar and Kapurthla districts of Punjab

Naturally occurring Radium (226Ra) and Radon (222Rn) concentration in the drinking water samples of 20 villages of Jalandhar and Kapurthla districts of Punjab has been determined for health risk assessment. Activity concentration of 226Ra and 222Rn in the studied water samples varies from 0.08 to 0.13 Bq l−1 and 1.42 to 5.26 Bq l−1, with the average concentration of 0.1 Bq l−1 and 3.51 Bq l−1 respectively. The dose to the internal parts of the body is received from 222Rn through inhalation and ingestion while 226Ra contributes dose mainly through ingestion. The annual average inhalation and ingestion dose from 222Rn in water in the studied area is 0.89 nSv a−1 and 0.74 μSv a−1. The mean annual ingestion dose from 226Ra in water is 18.73 μSv a−1. The total mean annual effective dose due to 226Ra and 222Rn in water is 19.46 μSv a−1. As the total annual effective dose due to 226Ra and 222Rn in water samples of the study area is lower than the reference dose level of 10 mSv, the health hazards related to these radionuclides are expected to be negligible.

National dose reference levels in computed tomography-guided interventional procedures-a proposal.

To establish national reference levels (RLs) in interventional procedures under CT guidance as required by the 2013/59/Euratom European Directive. Seventeen categories of interventional procedures in thoracic, abdominopelvic, and osteoarticular specialties (percutaneous infiltration, vertebroplasty, biopsy, drainage, tumor destruction) were analyzed. Total dose length product (DLP), number of helical acquisitions (NH), and total DLP for helical, sequential, or fluoroscopic acquisitions were recorded for 10 to 20 patients per procedure at each center. RLs were calculated as the 3rd quartiles of the distributions and target values for optimization process (TVOs) as the median. RLs and TVOs were compared with previously published studies. Results on 5001 procedures from 49 centers confirmed the great variability in patient dose for the same category of procedures. RLs were proposed for the DLPs and NHs in the seventeen categories. RLs in terms of DLP and NH were 375mGy.cm and 2 NH for spinal or peri-spinal infiltration, 1630mGy.cm and 3 NH for vertebroplasty, 845mGy.cm and 4 NH for biopsy, 1950mGy.cm and 8 NH for destruction of tumors, and 1090mGy.cm and 5 NH for drainage. DLP and NH increased with the complexity of procedures. This study was the first nationwide multicentric survey to propose RLs for interventional procedures under CT guidance. Heterogeneity of practice in centers were found with different levels of patient doses for the same procedure. The proposed RLs will allow imaging departments to benchmark their practice with others and optimize their protocols. • National reference levels are proposed for 17 categories of interventional procedures under CT guidance. • Reference levels are useful for benchmarking practices and optimizing protocols. • Reference levels are proposed for dose length product and the number of helical acquisitions.

Estimating inorganic arsenic exposure from rice intake in Chinese Urban Population

BackgroundRice intake is a major route of oral exposure to inorganic arsenic (iAs), a known human carcinogen. The recent risk assessment on iAs in rice conducted by the US Food & Drug Administration (FDA) didn’t propose an action level for iAs in rice mainly because of the relatively low consumption rate in the general US population. However, this decision may not be applicable to high rice-intake populations, such as the Chinese population. ObjectiveThe objective of this study was to probabilistically characterize the exposure of iAs via rice intake in Chinese population with a focus on the urban population. MethodsWith the consideration of bioaccessibility of iAs in rice, iAs exposure is mainly determined by rice intake rate and iAs concentration in rice. To estimate the daily rice consumption, a dietary survey consisting of 1873 subjects was conducted in three major Chinese cities (Beijing, Guangzhou, and Hangzhou). Speciated As concentration in rice was measured using 480 rice samples collected from markets in these three cities. Monte Carlo simulation approach was applied to distributionally estimate the average daily dose (ADD) of iAs through rice intake. ResultsThe estimated distribution of daily iAs exposure of the study population has a mean of 10.5 μg/day with a 95th percentile interval from 0.1 to 75.3 μg/day. The estimated distribution of ADD has a mean of 0.179 μg/kg/day with a 95th percentile interval from 0.001 to 1.224 μg/kg/day. Greater level of iAs exposure (due to higher rice intake) was observed in males than females, and in summer than other seasons with lower temperature. Geographically, the ADD of iAs exposure from rice intake reduces from south to north. ConclusionsAbout 13% of the Chinese urban population are exposed to iAs via rice intake higher than the Reference Dose (RfD) level.

The establishment of the national dose reference level (DRL) for head-CT examination in Indonesia

The dose reference level (DRL) is one of the tools for dose optimization in every radiological practice. However, Indonesia does not have a national DRL for CT which can be adopted nationally to date. This research was aimed to develop the national DRL for the head CT examination. There were 636 survey booklets with 20.211 patient data. All data then were classified into contrast and non-contrast parameters. Outliers data were removed from the data list by z-score. MATLAB R2017b was used to determine minimum, maximum, the first, second and third quartile values. The third quartile of data was identified as the DRL value. It was found that national DRLs in terms of CTDIvol, DLP, and effective dose were 60 mGy, 1,811 mGy-cm, and 3.8 mSv for the contrast parameter, and 61 mGy, 1,350 mGy-cm, and 2.8 mSv for the non-contrast parameter. National DRL values for males and females show the same value when stated in CTDIvol. Meanwhile, the national DRL value for males is greater than that for females when expressed in DLP and effective dose. These results are consistent with the differences in head size that is relatively larger in males than in females.

Radiation dose management in CT imaging: Initial experience with commercial dose watch software

In this study, a patient dose tracking software was utilised for the management patient doses and optimisation of scanning protocols for computed tomography (CT) imaging. This study aimed to evaluate the used of GE DoseWatch software for local dose tracking and management. The commercial DoseWatch software was first installed at Imaging Unit, Advanced Medical and Dental Institute, Universiti Sains Malaysia (AMDI, USM), Penang on November 2018. All the CT scans were tracked by this software connected on-line to the Siemens SOMATOM AS+ CT scanner and GE Discovery SPECT/CT scanner. A total of 361 CT dose dataset were evaluated during the period of 10 months started from November 2018 until August 2019. From the initial experience, this software allows rapid and reliable collection and management of the CT dose data involving large number of examinations. From comparative study with our established local dose reference level, the mean DLP for few CT protocols exceeded the LDRLs such as TAP (10%), Routine Brain (89%), and HeadRoutine (38%) CT study which need further assessment and audit on the current local CT protocols. However, implementation of the software required knowledgeable and well-trained user for the full-benefits. Accurate data and protocol types should also be selected by the users during the CT scanning as it will influence the whole process of dose tracking and management on the software.

Variation of Pediatric Doses Undergoing Digital and Computed Radiography Examination in Addis Ababa, Ethiopia.

Various researchers who carried out national and international surveys have reported wide variations in patient dose arising from specific X-ray examinations. Thus, assessment of radiation dose is an essential part in the optimization process. The aim of this study was to compare the entrance surface doses delivered to pediatric patients undergoing digital and computed radiography X-ray examination. A cross-sectional study was conducted on 389 pediatric X-ray projections less than 15 years of age on eight X-ray machines in Addis Ababa in February 2009 E.C. The tube output of the X-ray machines in air was measured using RaySafe XI dosimeters. Then, entrance surface dose was estimated for common x-ray examinations like chest, skull, extremities and pelvis using established relation between X-ray tube output and radiographic parameters. These data were analyzed statistically using computer (Excel and SPSS method). The third quartile estimated ESDs in mGy for both computed and digital radiography examinations of chest (AP) for age (0-1 year) were 0.24 and 0.15, (1-5 year) 0.3 and 0.16. For the age group (5-10 year), it was 1.97 and 0.26 and for the (10-15 year) group, 0.56 and 0.18 respectively. These values were higher than those of the United Nations Scientific Committee's on the Effects of Atomic Radiation's established dose reference levels (in mGy for age (0-1 year) 0.02, (1-5 year) 0.03, (5-10 year) 0.04, and (10-15 year) 0.05 respectively). The wider dose variation between computed and digital radiography shows that there is a pressing need to minimize the detriment caused by unnecessary computed radiography.

Evaluation of radiation dose from coronary CT angiography (CCTA) examination associated with prospective ECG-triggering technique in multidetector 640-slice scanner

In this study we evaluate radiation dose from a prospective ECG-triggered coronary CT angiography (CCTA) examination multidetector 640-slice CT and compares with other establish references. A total of 98 patient subjects were fall into inclusion criteria and related parameters has been recorded and analysed. It was estimated that the effective dose was at 5.23 ± 4.38 mSv (range 1.34 to 20.35 mSv) and it was significantly lower than that stated in the national dose reference level (NDRL) with 57% difference. It is highly recommended that the practice of using prospective ECG-triggering CCTA with low scanning range provides an optimum amount of radiation dose when compared to previous practice.

Are the reference values for exposure to radiation during cardiac device implantation needed?

The paper comments an attempt of investigators of a multicenter, prospective observational trial to assess patient and staff radiation exposure during cardiac device implantations and define dose reference levels for such procedures.

A MULTICENTRE SURVEY OF LOCAL DIAGNOSTIC REFERENCE LEVELS AND ACHIEVABLE DOSE FOR CORONARY ANGIOGRAPHY AND PERCUTANEOUS TRANSLUMINAL CORONARY INTERVENTION PROCEDURES IN KOREA.

Interventional cardiology procedures can involve relatively high radiation doses compared to general radiography. During coronary angiography (CAG) and percutaneous transluminal coronary intervention (PCI), the same area is exposed to radiation for a long period. In this study, radiation exposure data of 1071 examinations in Korean hospitals were collected, and the achievable dose (AD) and diagnostic reference levels (DRLs) in actual medical practice for two types of interventional cardiology procedures in Korea were established. In CAG, 75th percentile DRLs and AD of the total kerma-area product were 47.0 and 33.1 Gy·cm 2, respectively. In PCI, those values were 171.3 and 102.6 Gy·cm2, respectively. This is the first study to introduce the DRLs for cardiovascular interventional procedures in Korea. These results will help optimise the interventional cardiology procedures for Korean cardiac centres.

Age-dependent effective ingestion dose estimations and lifetime risk assessment for selected radionuclides (40K and 3H) in bottled waters marketed in United Arab Emirates

Monitoring drinking water, including bottled water, is imperative to safeguarding public health especially where bottled water consumption is high like in the United Arab Emirates (UAE). In this study, radionuclide activity levels of Tritium (3H) and Potassium (40K) were assessed in various brands of bottled water marketed in UAE. Activity level data was used to calculate the annual effective doses (Ed) for different age groups, and the excess lifetime cancer risk (ELCR) for adult males and females in the UAE population. Activity levels for both radionuclides were below the allowable maximum guideline values specified by local and international standards. Calculated total age dependent ingestion doses revealed that adults and lactation age groups received the highest effective ingestion doses. Adult males exhibited a higher ELCR for both isotopes, compared to females. Nonetheless, total radioactive dose for each water brand (0.91–1.47 μSv/yr) as well as for each population group were well below the recommended annual reference dose level of 100 μSv set by World Health Organization. Therefore, bottled water in the UAE is safe from the radiological aspect for investigated radionuclides, and poses no significant radiological exposure and health risk to the public.

Neurointerventionalist and Patient Radiation Doses in Endovascular Treatment of Acute Ischemic Stroke.

To evaluate the patient and the neurointerventionalist radiation dose levels during endovascular treatment of acute ischemic stroke, and to analyze factors affecting doses. From October 2017 to January 2019, we prospectively collected patient radiation data and neurointerventionalist data from real-time dosimetry from all consecutive thrombectomies. Multivariate analysis was performed to analyze patient total dose area product (DAP) and neurointerventionalist dose variability in terms of clinical characteristics and the technical parameters of thrombectomies. Local dose reference levels (RL) were derived as the 75th percentile of the patient dose distributions. A total of 179 patients were treated during the study period and included in this study. Local dose RL for thrombectomy was derived for total DAP to 34Gycm2, cumulative air kerma of 242mGy and fluoroscopy time of 12min. The mean neurointerventionalist dose for thrombectomy was 7.7 ± 7.4µSv. Height (P = 0.018), weight (P = 0.004), body mass index (P = 0.015), puncture to recanalisation (P < 0.001), fluoro time (P < 0.001), number of passes (P < 0.001), thrombolysis in cerebral infarction 2b/3 recanalisation (P = 0.034) and aspiration thrombectomy (P < 0.001) were independent factors affecting patient total DAP, whereas baseline National Institutes of Health Stroke Scale (P = 0.043), puncture to recanalisation (P = 0.003), fluoroscopy time (P = 0.009) and number of passes (P = 0.009) were factors affecting the neurointerventionalist dose. New reference patient doses lower than those in previously published studies were defined. However, the operator's doses were higher than those in the only available study reporting on operator's dose during cerebral interventions.

Monitoring Radiation Exposure During Surgery with Real Time Measurements: Opportunities and Limitations

In Germany, staff exposed to radiation is monitored with official individual dosimeters. Commercially available real-time dosimeters (RTD) can be used as radiation protection dosimeters. They are worn over the apron and display the radiation dose being measured at the desired location at intervals of one second. These real-time radiation exposure measurements enable the surgical staff to take suitable measures to reduce the radiation during the operation. The objective of our study was to monitor the accuracy of the measurements taken from the real-time dosimeter and to determine the radiation scatter for individual members of the surgical staff. Prospective measurements of the operating team's exposure to radiation were carried out using a real-time dosimeter system in an operating room for vascular surgery equipped with a C-arm. Firstly the calibration of the RTD at the operating table was checked using a water phantom. Subsequently, measurements were taken during vascular interventions and surgery. When calibrated, the values of the individual RTD revealed internal significant deviations, thus a corrective factor was calculated for each RTD. In total 55 interventions on 53 patients were studied. The average dose for the RTD of the surgeon during endovascular aortic repair (n = 11) amounted to 9 ± 9 µSv (range 3.6 - 50 µSv) and during thoracic endovascular aortic repair (n = 6) 35 ± 49 µSv (3.8 - 190.3 µSv). In the case of percutaneous transluminal angioplasty of the pelvis and of the lower extremities (n = 20), the average dose for the RTD of the surgeon was 7 ± 7 µSv (1.2 - 35 µSv) and for the angiographies of the lower extremities (n = 12) at 2 ± 3 µSv (0.2 - 15.9 µSv). The real-time dosimetry provided data which contributed to the operating team changing their behaviour in the operating room. Since the dose values determined by the official dosimetry are generally very low, it is not possible to optimise the behaviour and thus the radiation protection using these dose values. This can be achieved with the radiation protection dosimeter and the dose reference levels can be defined in the new Radiation Protection Ordinance (StrlSchV). Instant feedback of the current dose rate at the place where the RTD is worn can lead to both the individual adjusting his or her personal behaviour and to optimisation of the individual's radiation protection. It is only possible to compare the measured data obtained with the RTD when calibration is carried out in advance.

Assessment of commited effective dose from drinking water available to anyigba dwellers, north central Nigeria

The study of the committed effective dose from drinking water available to Anyigba dwellers have been carried out using a background Gasless Alpha-Beta Counting System (Protean Instrument Corporation) – MPC 2000DP. The gross alpha and gross beta activity concentrations of the collected water samples were below the safe limits of 0.5 Bq/l and 1 Bq/l respectively, as recommended by the world health organization (WHO). Also, results of the committed effective dose calculated were all below the reference dose level (RDL) of 0.1mSv/yr. Hence, Anyigba dwellers are radiologically safe as they consume their water from the various sources studied in this research work.

Estimating reference dose measurements during common computed tomographic procedures

Background: Medical X-rays are the largest man-made source of public exposure to ionizing radiation. In CT examination, the probability of radiation-induced cancer is more than other x-ray examinations. Objective: The aim of this research is to estimate the reference dose values for some common procedures (head and abdomen) and compare the findings with those of a previous research. Methods: Dose measurements were taken from the scanner readings, and using the periphery of the PMMA phantom, the body phantom and head were found to be about 32 cm and 16 cm in diameter, respectively. The volume computed tomography (CT) dose index (CTDIvol) carefully chosen in the small phantom was used as a benchmark for a CT head, and the measure in large phantom was utilized as a benchmark for body CT. The results of the average estimated CTDIvol for the head-and-abdomen scans in the emergency department of a large hospital and large diagnostic clinic scanner were compared with international reference dose levels. Results: In this study, the average values of CTDIvol were 53.02 mGy and 16.95 mGy for the head and abdomen, respectively. The dose for the head phantom, 53.02 mGy, was perceived to be inferior in differentiation with international diagnostic reference level (DRL) doses. The estimated dose for the abdomen scan was elevated in comparison with 2004 European DRLs by 13%, but it was lower than the DRL for ACR by 32%. Conclusion: The results presented here will assist by collectively providing a fixed reference point for determining reference doses for CT examinations.

Assessment of Diagnostic Reference Dose Associated with Computed Tomography Examination

The current study is aimed to estimate the diagnostic reference dose levels (DRLs), the volume computer tomogram dose index (CTDIvol), the CT air kerma-length product (PKL,CT) and the effective dose (E) for head, chest and chest-abdomen-pelvic CT examinations performed on adults in King Abdullah Medical City (KAMC), Saudi Arabia. Demographic parameters (such as age, gender, weight, height) for a sample of 535 computed tomography (CT) patients and physical scan parameters (such as patient tube voltage (kV), reference and effective mill ampere-second (mAs), scan length, number of slices, and pitch factor) were collected from a picture archiving and communication system (PACS). CTDIvol and PKL,CT were studied for different patients weights (40 -60 kg, 60-80 kg, 80-100 kg and 100-120 kg). Mean CTDIvol, PKL,CT and effective dose for a standard weight (70 kg ±10%) was evaluated according to the three CT protocols considered and the results were, as follows: for head examinations – 61.8 mGy, 1212 mGy.cm and 2.55 mSv, respectively; for chest examinations- 13.1 mGy, 657.5 mGy.cm and 9.21 mSv, respectively; for chest-abdomen-pelvic examinations - 13.9 mGy, 782.5 mGy.cm and 11.73 mSv, respectively. The effective dose for the chest examinations was lower than the corresponding value communicated by the European study group under European Commission. The effective dose for head examinations, was slightly higher than the one communicated by the European Commission study due to differences in the scan length. It needs optimizing the radiation dose delivered to patients via periodical review of scan parameters for a protocol under study.

Radiation exposure during cardiac device implantation: Lessons learned from a multicenter registry.

Little data are available about radiation exposure during cardiac electrical device implantation, and no dose reference levels have been published. This multicenter, prospective, observational study assesses patient and staff radiation exposure during cardiac device implantations, and aims at defining dose reference levels. Patient demographic, procedural, and radiation data were obtained for 657 procedures from nine institutions. Physician and staff exposure were measured using real-time dosimeters worn beneath and above lead apron. Statistical analysis included fluoroscopy time (FT), dose-area product (DAP), and DAP adjusted for FT and body mass index. Pacemakers and cardioverter defibrillators were implanted in 481 and 176 patients, respectively. Of these, 152 were treated with cardiac resynchronization therapy (CRT). Median FTs were 837s (interquartile range [IQR]: 480-1323), 117s (IQR: 69-209), and 101s (IQR: 58-162), and median DAPs were 1410 (IQR: 807-2601), 150 (IQR: 72-338), and 129 (IQR: 72-332) cGy.cm² for biventricular, dual chamber, and ventricular device implantation, respectively. Dose reference levels correspond to the third quartile values. During CRT, higher exposure was observed with four X-ray systems than with the two newer and customizable ones (adjusted DAP of 0.90 [IQR: 0.26-1.01] and 0.29 [IQR: 0.23-0.39], respectively; P<.001). Based on real-life measurements, this multicenter registry provides dose reference levels and may help centers assess radiation exposure. Although biventricular device implantation was responsible for the highest radiation exposure, FT was meaningfully shortened compared to previously reported values. For a same FT, the use of new generators and custom settings has significantly reduced DAP.

A MULTICENTRE SURVEY OF LOCAL DIAGNOSTIC REFERENCE LEVELS AND ACHIEVABLE DOSE FOR CORONARY ANGIOGRAPHY AND PERCUTANEOUS TRANSLUMINAL CORONARY INTERVENTION PROCEDURES IN KOREA

Interventional cardiology procedures can involve relatively high radiation doses compared to general radiography. During coronary angiography (CAG) and percutaneous transluminal coronary intervention (PCI), the same area is exposed to radiation for a long period. In this study, radiation exposure data of 1071 examinations in Korean hospitals were collected, and the achievable dose (AD) and diagnostic reference levels (DRLs) in actual medical practice for two types of interventional cardiology procedures in Korea were established. In CAG, 75th percentile DRLs and AD of the total kerma-area product were 47.0 and 33.1Gy·cm 2, respectively. In PCI, those values were 171.3 and 102.6Gy·cm2, respectively. This is the first study to introduce the DRLs for cardiovascular interventional procedures in Korea. These results will help optimise the interventional cardiology procedures for Korean cardiac centres.

Risk bases can complement dose bases for implementing and optimising a radiological protection strategy in urgent and transition emergency phases

Current radiological emergency response recommendations have been provided by the International Commission on Radiological Protection and adopted by the International Atomic Energy Agency in comprehensive Safety Standards. These standards provide dose-based guidance for decision making (e.g., on sheltering or relocation) via generic criteria in terms of effective dose in the range from 20 mSv per year, during transition from emergency to existing exposure situation, to 100 mSv, acute or annual, in the urgent phase of a nuclear accident. The purpose of this paper was to examine how such dose reference levels directly translate into radiation-related risks of the main stochastic detrimental health effects (cancer). Methodologies, provided by the World Health Organization after the Fukushima accident, for calculating the lifetime and 20 year cancer risks and for attributing relevant organ doses from effective doses, have been applied here for this purpose with new software, designed to be available for use immediately after a nuclear accident. A new feature in this software is a comprehensive accounting for uncertainty via simulation technique, so that the risks may now be presented with realistic confidence intervals. The types of cancer risks considered here are time-integrated over lifetime and the first 20 years after exposure for all solid cancers and either the most radiation-sensitive types of cancer, i.e., leukaemia and female breast cancer, or the most radiation-relevant type of cancer occurring early in life, i.e., thyroid. It is demonstrated here how reference dose levels translate differently into specific cancer risk levels (with varying confidence interval sizes), depending on age at exposure, gender, time-frame at-risk and type of cancer considered. This demonstration applies German population data and considers external exposures. Further work is required to comprehensively extend this methodology to internal exposures that are likely to be important in the early stages of a nuclear accident. A discussion is provided here on the potential for such risk-based information to be used by decision makers, in the urgent and transition phases of nuclear emergencies, to identify protective measures (e.g., sheltering, evacuation) in a differential way (i.e., for particularly susceptible sub-groups of a population).

Investigation of Radiation Exposure of Patients with Acute Ischemic Stroke during Mechanical Thrombectomy.

In radiological interventions, the skin is the most exposed organ. The aim of this study was to investigate the local dose exposure and the resulting risk of deterministic radiation effects for patients who underwent mechanichal thrombectomy. The examination protocols of 50 consecutive stroke patients who underwent mechanical thrombectomy from September 2016 to April 2017 were evaluated in this study. All procedures were performed on a biplanar angiographic suite. The local skin equivalent dose H P(0.07) was calculated retrospectively using the recorded radiation data and previously measured conversion factors. The in-vitro determination of the conversion factors was performed with a silicon semiconductor detector on the surface of an Alderson-Rando head phantom depending on the radiation quality. Vessel occlusion was located in the M1 and M2 segments of the cerebral artery media (n = 32), the internal carotid artery or carotid-T (n = 12) and the basilar artery (n = 6). The fluoroscopy times ranged from 5.7 minutes to 137.3 minutes with an average value of 39.5 ± 4.1 minutes. The determined skin equivalent dose values ranged from 0.16 ± 0.02 Gy to 4.80 ± 0.51 Gy, with the mean value being 1.00 ± 0.14 Gy. In 3out of 50 cases (6 %), the threshold value for skin reactions of 3 Gy published by the German Radiation Protection Commission was exceeded. A further 15 patients (36 %) were exposed to a dose of 1-3 Gy. The highest dose values were achieved during long procedures with occlusions in the posterior circulation and carotid occlusions. In addition, a local dose reference level of 1.24 ± 0.15 Gy could be determined for the skin equivalent dose in mechanical thrombectomies for our center. Even during a modern neuroradiological intervention, such as mechanical thrombectomy, radiation doses to the patient are produced and can lead to deterministic radiation damage to the skin in approximately 6 % of cases. Systematic monitoring of local dose quantities, such as H P(0.07), seems appropriate. Possibilities for recording and reducing the local dose load should be developed by the interventional teams in cooperation with a medical physics expert. · In 64 % of the thrombectomies the skin equivalent doses were in the harmless range (< 1 Gy).. · In 6 % of the patients higher H P(0.07) values were determined, which can lead to deterministic radiation damage to the skin.. · To avoid deterministic damage during neurointerventions, H P(0.07) should be recorded (combined measuring chambers).. · For longer interventions, precautions should be taken to reduce the radiation dose.. · Bärenfänger F, Block A, Rohde S. Investigation of Radiation Exposure of Patients with Acute Ischemic Stroke during Mechanical Thrombectomy. Fortschr Röntgenstr 2019; 191: 1099 - 1106.

Evaluation of radiation risks during CT brain procedures for adults

The purpose of this study is to evaluate the patients’ radiation dose in three different modalities of CT scanners (64, 16 and 2 slices) and the biological effects during CT brain examinations.A total of 60 patients were examined in three different hospitals in Morocco. The data were collected from CT Brain examinations at of 20 CT scans per hospital. For each examination, we have reported CT acquisition parameters including the number of series, use of contrast medium; tube kV, tube current and rotation time, slice thickness as well as the displayed CT dose index (CTDIvol) and the Dose Length Product (DLP). Cancer and biological heredity risks were estimated using the International Commission on Radiological Protection (ICRP) conversion factors.The average dose values for CT brain for 2 slices was 305±112mGy.cm. The mean dose value for 16 slices was 716±179mGy.cm, while the average dose for 64 slices was 1136±708mGy.cm. The patient cancer risks per procedure ranged between 4 and 13 per 105 CT procedures. This risk is 4, 8 and 13 per 105 CT procedures for 2 slices, 16 slices and 64 slices respectively. The patient heredity risks varied between 1 and 5 per million CT procedures. It is 1, 3 and 5 for 2 slices, 16 slices and 64 slices respectively.Dual slice scanner delivered the least effective dose while 16 and 64 slice scanners delivered the highest effective dose. The dose values of this study were comparable to the international reference levels of CT examination. CT dose optimization protocol is not implemented in the Moroccan hospitals. These values could be used as our hospital's Dose Reference Levels (DRL) until a more detailed study survey can be conducted in Morocco for the establishment of the country's reference levels.