This study aims to estimate the risks associated with the cosmic radiation dose received by crews and passengers on internal flights departing from Fez. The methods used are SIEVERT and the mathematical model which provides an estimate of the effective doses based on flight parameters are the flight duration, the atitude, the laltitude. The total cancer risk and genetic effects were estimated according to the ICRP. The effective doses determined by the SIEVERT and the mathematical model for the departure airport of Fez to the different national destinations are as follows: The measured dose values ranged from 0.40 µSv to 0.90 µSv and the calculated effective dose values ranged from 1.44 µSv to 2.21 µSv. The risk of cancer with aircrew members and passengers computed ranged from 17×10−5 to 28×10−5 and 30×10−6 to 53×10−6. And also, the risk of effects genetic with flight crews and travelers computed ranged from 3×10−5 to 5×10−5 and 7×10−6 to 12×10−6. The results of the calculation differ with the measurements for internal flights from Fez. To mitigate the risk of potential health effects, safety measures must be taken to lower the dose.

Radiation therapy plays an important role in the treatment of malignant tumour. The quality control for linear accelerator is one of the keys to ensure the correct and safe implementation of accurate radiotherapy.The National Center of Oncology in Nouakchott is equipped with a linear accelerator which provides two energies in photon regime 6 MV and 18 MV.The aim of this work is to control the quality of this accelerator by comparing the measured results with those calculated with Treatment Planning Systems(TPS).The percentage depth dose (PDD), the main parameter generally used to verify the accelerator quality,was measured by ionization chambers (PTW 0.125 cm3).The PDD measures have been determined for 6MV and 18MV beam photon energy, for four different dimensions of the field size. The measured results by the ionization chamber are comparable for all chosen treatment field dimensions to those calculated by TPS.

Objective: This study aims to establish diagnostic reference levels and radiation-induced risk for the diagnostic CT-scans and the radiotherapy planning CT-scans of the thorax in the regional hospital of Agadir, Morocco. Materials and methods: Data from two groups of patients undergoing thoracic CT-scans with either diagnostic CT-scans (G1, n=120) or radiotherapy planning CT-scans (G2, n=120) are collected. All acquisitions were helical. DRLs is calculated for each type of thoracic CT-scan by estimating the 75% percentile of the CTDIvol and the DLP. The total cancer risk RC was calculated according to the ICRP publication 103. The data are statistically analyzed by SPSS Statistics V21.0. The student's t-test was used to establish the relationship between gender, clinical indication, and effective dose. The Spearman test was used to establish the relationship between age, BMI, and effective dose. Results: DRLs in terms of CTDIvol and DLP for radiotherapy planning of thorax were 19.37 mGy and 851.9 mGy cm, respectively. In diagnostic CT-scans, DRLs in terms of CTDIvol for pulmonary embolism, infectious lung disease, Chronic Obstructive Pulmonary Disease (COPD) were 11.13 mGy, 10.26 mGy, and 7.37 mGy respectively, and DRLs in terms of DLP were 417.73 mGy cm, 451.9 mGy cm and 317.78 mGy cm respectively. The cancer risk for radiotherapy planning CT-scans is ranged between 209 and 1564 with a mean value of 715 per 1 million of CT-scan. For diagnostic CT-scans, the cancer risk is ranged between 199 and 626 with a mean value of 357 per 1 million for pulmonary embolism, between 238 and 668 with a mean value of 369 per 1 million for infectious lung disease, and between 130 and 393 with a mean value of 244 per 1 million for COPD. Conclusion: Optimizing the doses received by patients in medical imaging, particularly CT, has become an obligation. Reviewing practices and procedures and promoting a radiation protection culture can help to better manage the radiation doses received by the patient.

This work aims to calculate size-specific dose estimates (SSDE) and establish the relationship between water equivalent diameter (Dw) values and SSDE in images of abdominal CT examinations undergone by 30 adult patients. These patients had a mean age of 51 years, a mean height of 164 cm, and a mean weight of 62.71 kg. The water equivalent diameters (Dw) measured 25.30 cm on average, with mean volumetric computed tomography dose index (CTDIvol) doses of 7.95 mGy and a mean SSDE of 11.31 mGy. Images were retrospectively collected using a Hitachi Supria 16-slice CT scanner, and Dw and SSDE values were calculated based on lateral and anteroposterior (LAT + AP) measurements of cross-sectional images from each CT examination. Dw was calculated from ED, and their close correspondence allowed for interchangeable use, following AAPM guidelines. The calculated doses (SSDE) were significantly higher than the doses displayed by the scanner (CTDI). Furthermore, a strong correlation (R2 = 0.63) was observed between SSDE and Dw. Consequently, assessing patient dose based on size becomes essential to optimize radiation exposure in CT imaging.

Pelvimetry is performed at the late pregnancy to measure the size of the pelvis through its different diameters in order to determine the possible modalities of delivery: by natural way or by programmed cesarean section. When a pregnant woman undergoes a radiological examination, the risk associated with radiation exposure is of concern. In general, the fetal dose cannot be measured directly, so Monte Carlo (MC) methods are used for this purpose. Therefore the objective of this study is to evaluate the fetal dose during a Computed Tomography (CT) pelvimetry examination by means of a MC method using Geant4 Application for Tomographic Emission code (GATE). A simulation of a CT pelvimetry examination was performed by modeling a Hitachi Supria 16-slice scanner that follows a CT pelvimetry protocol. A 16-diameter phantom is used to model the fetus inside a 32-diameter phantom that represents the patient's body. The fetal dose in this simulation was 0.95 mGy. Other studies on fetal dose from pelvic CT scans found that it does not exceed a few mGys, which is not a real concern. On another hand, the dose showed a dependence on the variation of the tube current and also the voltage. Therefore, these parameters can be used as a basis for action to reduce exposure and limit risk during such examinations.

The aim of this work was the characterization of the neutron flux parameters in two irradiation facilities; pneumatic tube system (PTS) and rotary specimen rack (RSR); at the Moroccan Triga Marck II research reactor using k 0 -IAEA and KayWin softwares. The analysis of several combinations of flux monitor sets is the basis for this study. The efficiency calibrations of the detector used have been carried out using the k 0 -IAEA software and then exported to the KayWin software for the determination of the f (thermal to epithermal neutron flux ratio) and α (deviation from the 1/ E distribution) parameters.

The consequences of radiological accidents outside the nuclear sector can be fatal. Therefore, emergency response plans must take into consideration the worst scenarios. This article presents a simulation of an accident in which it was assumed that the assembly of cobalt-60 sources from the irradiator installed at National Institute of Agronomic Research (NIAR) of Tangier was found on the ground. The Monte Carlo GEANT4 code was used to estimate the equivalent dose rate in the organs of an individual presented by an anthropomorphic phantom at different distances, and its variance with decreasing activity, this simulation will allow as to make the best decisions, correct actions, prevent serious radiobiological damage and to prepare the best methods of intervention in the occurrence of this scenario.

A pelvimetry examination is sometimes prescribed to a pregnant woman at the end of her pregnancy in order to assess the dimensions of her pelvis prior to childbirth. This examination has long been performed by using X-ray, but is now increasingly being replaced by CT-scan The objective of this study is to assess the radiation doses received during a practical CT pelvimetry examination performed using a Hitashi Supria 16-slice CT scanner. The radiation doses were estimated using Monte Carlo (MC)-based simulation with GATE code to model the 16-slice CT scanner machine. The GATE code operates using GEANT4 libraries. A polyymethyl metacrylate (PMMA) acrylic phantom of 32 cm diameter was modeled to represent the patient's body. X-ray energy spectrum generated using the SRS-78 spectrum processor was used for simulation. The simulation was executed with the same exposure parameters as the practical CT pelvimetry examination with dose parameters of 1 mGy, 0.9 mGy, and 36.6 mGy.cm, respectively, for the weighted CT dose index (CTDIw), the volume CT dose index (CTDIvol), and dose-length product (DLP). The MC simulation results provide dose parameters of 1.16 mGy, 1.07 mGy, and 43.6 mGy.cm, respectively, for the CTDIw, CTDIvol, and DLP. The differences between the simulation and the practical examination were 16 %, 18 %, and 18 %, respectively. These differences are considered in a quite good agreement. The results were also consistent with other similar studies. This work proves that the Monte Carlo simulation with the GATE code is usable to assess the patient doses during a CT pelvimetry examination.

The main objective of this study was to compare the mono-isocentric technique (MIT) with the skin-source distance (SSD) technique during radiotherapy breast cancer treatment. The results obtained show that the total number of Monitor Unit (MU) is always lower in MIT. The irradiation of target volumes was significantly improved with the MIT compared to the SSD technique, as well as the homogeneity of the dose distribution. The protection of organs at risk was significantly better with MIT. This study showed that MIT is better than SSD technique; we recommend its implementation in clinical practice for breast cancer radiotherapy treatment.

The objective of this study is to evaluate the radiation dose received by patients during a CT scan of the lumbar spine and to define the local diagnostic reference levels (DRLs). Data from 95 adult patients were collected during 1 month from one Moroccan hospital. Dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were evaluated by determining the 75th percentile as diagnostic reference levels for the lumbar spine computed tomography examination. The DRLs for this exam were compared with other studies. Moroccan local DRLs for adult lumbar spine CT have been determined in terms of DLP and CTDIvol, and they were 844.20 and 32.50, respectively. These DRLs for CTDIvol and DLP were higher than those for Australia and Cameroon and lower than those for Algeria. These comparisons have identified high doses to this examination. Therefore, it is necessary to apply dose optimization while keeping a good image quality for a reliable diagnosis.

This work aimed to evaluate the impact of tube current on spatial resolution and volumetric computed tomography dose index (CTDIvol) at abdominal CT examinations. The measurements have been performed on HITACHI CT 16-slice Scanner using twophantoms (PMMA and Catphan 500) for evaluating the CTDIvol and spatial resolution. two tube voltages of 120KVp and 100KVp have been used while varying the tube current settings from 155 to 300 (mAs). The scanning at 100KVp compared to 120KVp has resulted in a dose reduction up to 38% at tube currents ranging from 100 to 300 (mAs) with a slight decrease in spatial resolution. This work has shown that it is possible to reduce the dose without affecting the spatial resolution by lowering the tube voltage from 120KVp to 100KVp.Keywords: Abdominal CT; CTDIv; Image Quality; Phantom.

Size-specific dose estimates (SSDE) are the latest topic of interest in patient radiation–dose studies in computed tomography (CT). The aim of this study is to calculate and evaluate the doses (SSDE) by measuring the effective diameter (ED) of cross-sectional images collected during CT examinations of the chest and abdomen in Moroccan hospitals. Doses (SSDE) were calculated based on cross-sectional images by measuring the effective diameters of 75 patients in both examinations (45 for the thorax and 30 for the abdomen). Specific conversion factors for (ED) were used to convert the registered CTDIvol to SSDE, according to the instruction in the American Association of Physicists (AAPM) Report 204. In thoracic CT, the CTDIvol and SSDE values ranged from 5.8 to 10.7 mGy (mean: 8.08) and 9.55 to 15.37 mGy (mean: 12.13), respectively. For abdominal CT, CTDIvol and SSDE values ranged from 4.8 to 12.2 mGy (mean: 7.95) and 8.01 to 14.15 mGy (mean: 11.31), respectively. The results show that the SSDE is a useful tool and could potentially educate CT operators on its effective use as a way to optimize radiation dose instead of CTDIvol, in particular to establish diagnostic reference levels.

Since the installation of the TRIGA MARK II reactors in the National Centre for Nuclear Energy, Science and Technology (CNESTEN), Neutron Activation Data Analysis software (NADA) for neutron activation analysis (NAA) based on the relative method was the first software used; Over the years, the neutron activation analysis laboratory has been seeking to develop other softwares based on k0-INAA standardization namely the K0-IAEA software and the k0 software for Windows. In this paper we will focus on the comparison between the performance of k0 software for Windows and NADA. We compared the results obtained by the NADA Software and k0 for windows for the same input parameters (sample mass, nuclear data, net peak area for the same gamma line and cooling measurement times). In the neutron activation analysis laboratory of the National Center for Nuclear Energy, Science and Technology (CNESTEN) we analysed several reference materials (RM) or certified reference materials (CRM) and WEPAL samples. In this analysis, only certified or recommended values were used to compare the two processes for the different elements.

Head CT is a fast and non-invasive method of imaging the brain and skull. It can be used after a cerebral trauma to identify a skull fracture, cerebral edema or a cerebral hematoma. In other cases, it is prescribed in the presence of symptoms suggesting a lesion or a cerebral pathology such as violent headaches or epileptic fits. Children may be more sensitive to radiation and have a longer life span, leaving them at an increased risk of cancer than adults. The purpose of this study is to evaluate the detriment associated with exposure during pediatric CT examinations. Six radiology departments equipped with different CT machines calibrated according to international protocols were used in the study. In all, 180 patients underwent CT scans of the head. The effective radiation dose, cancer risk, and genetic risk were evaluated using the risk factor coefficients of the International Commission on Radiological Protection (ICRP). The effective dose for Moroccan hospitals is (2.70 +/- 065) mSv. The cancer risk per head CT scan ranged from 42 to 428 with a mean value of 148 per 1 million head CT examinations. The hereditary risk per brain CT scan ranges from 2 to 16, with a mean value of 5 per 1 million head CT examinations. The effective dose and risk associated with head CT scans were above the average for one-third of the hospitals in this study. The likelihood of cancer and hereditary risk is significant when multiple images are acquired. Almost 66% of the procedures performed with normal results in the study. Yet, staff still need to further optimize the radiation dose during brain procedures. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Network of Biomaterials and Engineering Science.

In Morocco, the radiation doses received by adult patients are increasing due to the number of CT examinations performed and the larger number of computed tomography (CT) scanners installed. The aim of this study was to evaluate the radiation doses received by patients for the most common adult CT examinations in order to establish local diagnostic reference levels (DRLs). Data from 1016 adult patients were collected during 3 months from four Moroccan hospitals. Dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were evaluated by determining the 75th percentile as diagnostic reference levels for the most common examinations including head, chest and abdomen. The DRL for each examination was compared with other studies. The established DRLs in Morocco in terms of CTDIvol were 57.4, 12.3 and 10.9 for CT examinations of the head, chest, abdomen, respectively. For DLP, they were 1020, 632 and 714, respectively. These established DRLs for CTDIvol were almost similar to the UK DRLs at all examinations, higher than the Egyptian DRLs and lower than the Japanese DRLs at the head CT examination, lower than the DRLs from Egypt and Japan at the CT abdomen examination. In terms of DLP, the DRLs were higher than those of the British studies, lower than those of the Egyptian and Japanese studies at the head CT examination were higher at chest CT and lower at abdominal CT than those of all selected studies. The higher level of established DRLs in our study demonstrates the requirement of an optimization process while keeping a good image quality for a reliable diagnosis.

This work aims to optimize the scanning parameters of Chest and Abdomen protocols in computed tomography, whilst maintaining imagequality and reducing the dose. Two phantoms have been used to evaluate the dose and image quality on a 16-slice HITACHI CT system by establishing the optimization threshold for each protocol. The proposed Thoracic protocol has shown a reduction in Computed Tomography Dose Index (CTDIvol) and Contrast-Noise Ratio (CNR), and the spatial resolution has remained stable with a slight increase in noise. For the optimized Abdominal protocol, CTDIvol has reduced significantly, noise has increased at the two new proposed energies of 100 and 120 kV, and CNR has decreased. This research has shown that by optimizing Chest and Abdomen protocols, substantial dose reductions may be achieved without compromising image quality when using a multi-slice Scanner.

Pediatric patients are well documented to be at higher risk of developing radiation-induced cancer than the average adult. This pilot study aims to estimate the radiation doses to pediatric patients during head Computed Tomography (CT), in order to establish local Diagnostic Reference Level (DRL). Data from 300 pediatric head CT examinations from 6 public hospitals were analyzed. The age group concerned is 5-10 years. The CT facilities were 64, 16, 4 and dual slice type. CT data included scanner acquisition parameters, the number of series, use of the contrast medium, rotation time, slice thickness, as well as the displayed CT Dose Index (CTDIvol) and the Dose Length Product (DLP). The effective dose and DRL were evaluated using the formalism and conversion factor of the International Commission on Radiological Protection (ICRP). The overall mean CT dose per procedure from different facilities was 44,97 mGy, 883,67 mGy.cm and 2,81 mSv for CTDIvol, DLP and effective dose, respectively. The mean third quartile dose per head CT procedure from all facilities was 40,94 mGy and 969,90 mGy.cm cm for CTDI and DLP, in that order. These results proved that pediatric patients are exposed to unnecessary doses of radiation during CT examination in public healthcare institution of Morocco. The DRL obtained was slightly higher than those established in some countries. Pediatric radiation dose per procedure indicated a wide variation between various hospitals and even in the same hospital for different patients. This pilot study showed the need for practices unification and radiation doses optimization during CT scan acquisition for pediatric patients in radiology departments.

The purpose of this study was to evaluate and compare the effect of acquisition parameters of the abdominal computed tomography protocol on image quality and dose quantities, including contrast-to-noise ratio (CNR), noise, spatial resolution (SR) as well as volumetric computed tomography dose index (CTDIv). The measurements have been done on a HITACHI 16-slice scanner using two phantoms (PMMA and Catphan 500), two tube voltages of 120KVp and 100KVp have been analyzed while varying the tube current settings from 155 to 300 (mAs) in order to measure the abdominal image quality quantities and dose (CTDIv). The scanning at 100KVp compared to 120KVp has resulted in a dose reduction up to 38% at mAs ranging from 100 to 300, a decrease in CNR of 28%, a slight decrease in spatial resolution accompanied with an increase in noise. This study has shown that despite the increase in noise at low tube voltages, it is possible to reduce the dose without affecting the quantities of spatial resolution and the contrast/noise ratio by lowering the tube voltage from 120KVp to 100KVp. Keywords: Abdominal CT; CTDIv; Image Quality; Phantom.

During Computed Tomography (CT) scan examinations, it is important to ensure a good diagnosis by providing the maximum information to detect pathologies and this can be done with a reduced dose. In this respect, several methods of dose reduction have been studied and evaluated. This work investigates the effect of tube voltage while varying the tube current on image quality and radiation dose at Chest CT examination. This study was conducted on HITACHI CT 16 slice Scanner using two phantoms for evaluating the dose and image quality; a PMMA phantom and a CATPHAN 500. Two tube voltages of 120 KVp and 100 KVp have been used for some variation of the tube currents (mAs) and recording the values of the measured quantities (CTDIv, spatial resolution, contrast to noise ratio CNR and noise). The scanning with 100 KVp at Chest CT examination led to a reduction in CTDIv until 45 %, an increase of noise from 17 % to 45 %, and the Spatial Resolution fell slightly (6 and 7 pl/cm) compared to the 120 KVp. The CNR shows a slight regression from 11 to 22 % for the 120 KVp and 100 KVp. This study has shown that despite the increase in the image noise at low tube voltage 100 KVp, it is possible to reduce the radiation dose by up to 45 % without degradation of image quality at Chest CT examination. Further works will evaluate the effect of acquisition parameters in other CT examinations.

This study aimed to estimate renal effective dose during abdominal CT scans in order to assess the renal risks of cancer and heredity per procedure in Moroccan hospitals. It’s consisted of examining a total of 120 patients referred to three radiology departments for an abdominal CT scan at the rate of 40 per hospital. The data that collected for this diagnostic exam included scanner acquisition parameters, number of series, use of the contrast medium, and rotation time as well as slice thickness, the displayed CT dose index (CTDIvol) and the Dose Length Product (DLP). Renal dose, effective dose and biological risks were estimated using the International Commission on Radiological Protection (ICRP) conversion factor. The patients included in this study were an average age of the (46.49 ± 14.16) years and an average weight of (73.34 ± 7.58) kg. For the mean effective dose (E) and average kidney dose (DK) received per patient during an abdominal CT scan, it were respectively of (6.67 ± 2.73) and (18.26 ± 7.74) mSv. The distribution of these values according to the hospital variable shows a difference in mean effective dose of the order of 0.26, 0.38 and 1.45 mSv and a difference in the mean renal dose of the order of 8.76, 4.94 and 0.48 mSv respectively for H1, H2 and H3. The induction cancer risk of abdominal and kidney per 105 procedures was respectively of 3 and 10. The kidney cancer risk by procedure is two to three times more likely than abdominal. For hereditary risk of abdominal and renal exposure per 106 procedures, it is 14 and 21 respectively. The renal stochastic effect by procedure is also two to three times more likely than that of the abdomen. Our values are relatively higher than those of published in some previous studies. Cancer risk and heredity estimation highlights the need to limit radiation dose. This first ever survey confirmed the need to improved training of health professionals involved in computed tomography on factors affecting image quality, doses and protocols optimization.