2021 NATIONAL DIAGNOSTIC REFERENCE LEVELS FOR PAEDIATRIC COMPUTED TOMOGRAPHY IN EGYPT.

OBJECTIVE: To establish national diagnostic reference levels (NDRLs) for most common paediatric computed tomography (CT) examinations in Egypt. METHODS: This was a prospective study that included all dedicated paediatric imaging centers in Egypt. Data from 1680 individual paediatric patients undergoing CT scanning of the head, chest and abdomen-pelvis were collected. Computed tomography dose indices were recorded, data were analysed and compared with the internationally published paediatric DRLs in14 countries. RESULTS: The Egyptian NDRLs of the CTDIvol (mGy) for head, chest and abdomen-pelvis scans among four paediatric age groups were found to be (23, 27, 28, 32, 4, 5, 6, 8, 5, 6, 7, 9) mGy, respectively; and the corresponding NDRLs of the DLP (mGycm) for head, chest and abdomen-pelvis scans were found to be (345, 428, 499, 637, 67, 85, 145, 215, 97, 135, 240, 320) mGycm, respectively. There were variations in the radiation doses between CT centers and identical scanners indicating the need for dose optimization. The NDRLs of the CTDIvol (mGy) and the DLP (mGycm) values were similar to or lower than international DRLs. CONCLUSION: This study summarizes the results of the first Egyptian Computed Tomography survey that provides national diagnostic reference levels for paediatric patients in Egypt. Despite the reasonable NDRLs values, the study depicted certain pros and cons concerning CT practice, and identified some problems that hinder the process of optimization as well as justification in children.

IAEA support to the radiation protection of patients in the time of the COVID-19 global pandemic.

The IAEA contribution to the radiation protection of patients during the global COVID-19 pandemic included a webinar on the use of CT and optimization for COVID-19 pneumonia, a survey with 137 responses from 84 sites across five continents, and a study on the CT utilization, protocols and patient doses with data from 62 healthcare sites from 34 countries. This paper outlines the main results of these efforts, which have been presented in the scientific literature and in several national trainings and international meetings.

Large differences in education and training of radiographers in Europe and Central Asia: Results from an IAEA coordinated study.

INTRODUCTION: Education and training of radiographers is known to be diverse between countries and regions. Under an IAEA project, this work collected data on radiographer education for the Europe and Central Asia region with a particular focus on radiation protection gaps and potential actions. METHODS: Following piloting, an electronic questionnaire was distributed to all national counterparts for the IAEA Technial Coopearation (TC) Europe region (n = 33 countries) and nominated national representatives. Contacts were additionally invited to a virtual workshop to discuss and rank common problems in education and training of radiographers and to propose potential solutions. RESULTS: Responses were received from 31 countries, including 14 from the European Union. Just over half of countries reported radiographer education being in higher education with 71% having program durations more than 3 years (range: 1 month-4 years). Programs included a spectrum of both clinical training and radiation protection hours with ten-fold variations noted across the region. Inclusion of core radiation protection topics within curricula varied similarly, as did radiographers' clinical involvement in both justification and optimisation between countries. Workshop participants identified five common training problems, namely education availability, lack of standardisation, radiation protection course quality, teamwork problems and lack of equipment. CONCLUSION: Radiographer education in the IAEA Europe region is heterogeneous with substantial differences in duration and quality of training programs between countries, which likely impact on quality of patient care delivered. Common problems have been identified and potential solutions proposed to focus quality improvement initiatives. IMPLICATIONS FOR PRACTICE: Radiographer education and training is diverse throughout the IAEA TC Europe region, with likely impacts on radiation protection practices applied. Clinical involvement of radiographers in justification and optimisation differs, potentially limiting adherence to radiation protection principles.

An international survey of imaging practices in radiotherapy.

Improvements in delivery of radiation dose to target tissues in radiotherapy have increased the need for better image quality and led to a higher frequency of imaging patients. Imaging for treatment planning extends to function and motion assessment and devices are incorporated into medical linear accelerators (linacs) so that regions of tissue can be imaged at time of treatment delivery to ensure dose distributions are delivered as accurately as possible. A survey of imaging in 97 radiotherapy centres in nine countries on six continents has been undertaken with an on-line questionnaire administered through the International Commission on Radiological Protection mentorship programme to provide a snapshot of imaging practices. Responses show that all centres use CT for planning treatments and many utilise additional information from magnetic resonance imaging and positron emission tomography scans. Most centres have kV cone beam CT attached to at least some linacs and use this for the majority of treatment fractions. The imaging options available declined with the human development index (HDI) of the country, and the frequency of imaging during treatment depended more on country than treatment site with countries having lower HDIs imaging less frequently. The country with the lowest HDI had few kV imaging facilities and relied on MV planar imaging intermittently during treatment. Imaging protocols supplied by vendors are used in most centres and under half adapt exposure conditions to individual patients. Recording of patient doses, a knowledge of which is important in optimisation of imaging protocols, was limited primarily to European countries.

The growing potential of diagnostic reference levels as a dynamic tool for dose optimization.

Diagnostic Reference Levels (DRLs) is an important tool that can improve radiation safety in medical imaging. However, there are certain aspects that need improvement and several obstacles that should be overcome before DRLs are fully implemented in practice. It is the authors belief that DRLs should be a dynamic tool that follows the development of clinical practice and technology advances. The establishment of adult and paediatric DRLs based on clinical indications should be considered as a priority. A common methodology and terminology is needed to allow for their clinical use. Dose monitoring systems can improve and accelerate the establishment, update and use of DRLs. However, certain steps need to be taken for proper collection. organization and analysis of big data. Availability of clinically qualified medical physicists in medical imaging departments, awareness on the importance of dose optimization and proper cooperation of relevant stakeholders are important prerequisites for the successful establishment and use of DRLs.

Guidance on prevention of unintended and accidental radiation exposures in nuclear medicine.

Nuclear medicine (NM) procedures for diagnosis and treatment of disease are performed routinely in hospitals throughout the world. These involve preparation and administration to patients of pharmaceuticals labelled with radioactive material. The International Atomic Energy Agency (IAEA) and the World Health Organisation highlighted the need for improvement in prevention of medical radiation incidents and accidents in the Bonn Call-for-Action in 2012. An IAEA Technical Meeting was held on prevention of unintended exposures and accidents in NM in 2018 to address the issue. Exposures can take place at any time when radioactive material is being produced and used, and the risk continues after procedures have been completed. Thus there is potential for staff or members of the general public to be exposed, as well as patients. This paper sets out guidelines for incident prevention based on presentations and discussions at the meeting, and review of reports from the literature. It deals with potential incidents in in-house radionuclide production, radiopharmaceutical preparation, administration to patients, and following a procedure, as well as aspects in management of radioactive materials. Special attention has been paid to therapeutic procedures, as these have the potential to cause more harm to patients from erroneous administrations, including tissue reactions from extravasation of radiopharmaceutical, and could lead to significant contamination events. Administration of NM therapy is generally contraindicated in pregnancy. Identification of any patient who may be pregnant is crucial and it might be necessary to verify this with a pregnancy test for patients within the age band considered to be fertile. Inclusion of NM therapy incidents in the IAEA automated reporting system SAFRON is recommended. In summary, the paper aims to highlight errors that could occur during different phases of NM procedures in order to aid prevention of incidents. The value of periodic audit in evaluating systems in place on a regular basis is emphasised. Approaches to incident investigation and follow-up are described, and the need to ensure corrective action is taken to address any deficiencies stressed.

Verbal and spatial working memory among drug-using HIV-infected men and women.

Working memory (WM) is a critical component of many neurocognitive functions. The literature has demonstrated consistently that WM impairment is more frequent and severe among substance-dependent individuals (SDIs) infected with HIV compared with uninfected SDIs; however, the SDIs who participated in these previous studies were primarily male. There are few published data on WM performance among HIV+ women with or without substance use disorders, and essentially no direct comparisons of WM performance between HIV+ men and women, regardless of substance use. We investigated potential sex and serostatus effects on WM among a sample of 360 SDIs (114 with HIV; 66% female) verified abstinent from alcohol and drugs of abuse at testing and generally comparable on substance use and comorbid characteristics. Participants were tested with the n-back task, a well-established WM measure that is sensitive to HIV-associated cognitive impairment. HIV+ men and women performed spatial and verbal versions of the n-back significantly less accurately compared with HIV- participants. Women showed slower response times compared with men on both versions, regardless of HIV serostatus. Individuals dependent on cocaine showed faster RTs compared with non-dependent users, but this effect was not apparent among opioid- or alcohol-dependent groups. Findings on n-back accuracy are consistent with our previous proposal that WM impairment represents a signature deficit among HIV+ SDIs; however, WM impairment appears less common among HIV+ women without a substance use history. The pattern of sex differences in response speed but serostatus effects on response accuracy is comparable to a recent report by our group of sex differences in learning speed but serostatus effects on delayed recall.

Collaboration, campaigns and champions for appropriate imaging: feedback from the Zagreb workshop.

Leading radiologists and representatives from national radiation protection regulatory authorities and health ministries from 19 countries of the European region worked together with five experts at the workshop on justification and appropriate use of imaging in Zagreb, Croatia, from 26 to 28 October 2017 jointly organised by the IAEA and the European Society of Radiology. The workshop served as a forum to exchange information on challenges and solutions for improving justification and the appropriate use of diagnostic imaging. Common barriers to improving the use of imaging referral guidelines were discussed and the need for increased collaboration identified. Examples of good practices were presented, including use of Clinical Decision Support (CDS) systems to facilitate rapid and good justification decisions. The workshop identified some of the needs of European countries for achieving more appropriate imaging proposing wider use of collaboration, campaigns and champions. MAIN MESSAGES: • Drivers for appropriate imaging in Europe are similar to those elsewhere globally. • Implementing imaging referral guidelines is the main barrier to more appropriate imaging. • Clinical Decision Support systems (CDS) facilitates good referral practice and justification decisions. • Collaboration, campaigns and champions may improve awareness, appropriateness and audit.

Lessons from two cases of radiation induced skin injuries in fluoroscopic procedures in Bulgaria.

BACKGROUND: Radiation-induced injuries to patient skin as a result of fluoroscopy guided interventional procedures are infrequently reported, often misdiagnosed and there is a need to learn lessons from every injury. METHODS: This paper describes two cases of radiation induced skin injuries that are, to the best of our knowledge, the first ever reported cases from Bulgaria and possibly from Eastern Europe, and would thus have educational value. RESULTS: The important messages from the skin injuries reported here are: lack of awareness among part of the interventional specialists about the potential for radiation induced skin injury, misdiagnosis after injury happened because of lack of awareness and knowledge among general physicians, dermatologists and surgeons who followed up cases of skin injuries; the lack of system to monitor patients with relatively high exposure; the important role played by the medical physicist in diagnosing the injury and overall in initiating actions; the role of training and informational material displayed in interventional facilities. CONCLUSIONS: For avoidance of skin injuries from interventional procedures it is of utmost importance to implement a system that includes (a) regular monitoring of radiation dose parameters of the procedure; (b) established trigger values for reporting;

Effects of sex and HIV serostatus on spatial navigational learning and memory among cocaine users.

Spatial learning and memory are critically dependent on the integrity of hippocampal systems. Functional MRI and neuropathological studies show that hippocampal circuitry is prominently affected among HIV-seropositive individuals, but potential spatial learning and memory deficits have not been studied in detail in this population. We investigated the independent and interactive effects of sex and HIV serostatus on performance of a spatial learning and memory task in a sample of 181 individuals with a history of cocaine dependence. We found that men showed faster times to completion on immediate recall trials compared with women and that delayed recall was significantly poorer among HIV-infected compared with HIV-uninfected participants. Additionally, a sex × serostatus effect was found on the total number of completed learning trials. Specifically, HIV-infected men successfully completed more learning trials compared with HIV-infected women. Results are discussed in the context of recent reports of sex and HIV serostatus effects on episodic memory performance.

Unintended and accidental medical radiation exposures in radiology: guidelines on investigation and prevention.

This paper sets out guidelines for managing radiation exposure incidents involving patients in diagnostic and interventional radiology. The work is based on collation of experiences from representatives of international and national organizations for radiologists, medical physicists, radiographers, regulators, and equipment manufacturers, derived from an International Atomic Energy Agency Technical Meeting. More serious overexposures can result in skin doses high enough to produce tissue reactions, in interventional procedures and computed tomography, most notably from perfusion studies. A major factor involved has been deficiencies in training of staff in operation of equipment and optimization techniques. The use of checklists and time outs before procedures commence, and dose alerts when critical levels are reached during procedures, can provide safeguards to reduce the risks of these effects occurring. However, unintended and accidental overexposures resulting in relatively small additional doses can take place in any diagnostic or interventional x-ray procedure and it is important to learn from errors that occur, as these may lead to increased risks of stochastic effects. Such events may involve the wrong examinations, procedural errors, or equipment faults. Guidance is given on prevention, investigation, and dose calculation for radiology exposure incidents within healthcare facilities. Responsibilities should be clearly set out in formal policies, and procedures should be in place to ensure that root causes are identified and deficiencies addressed. When an overexposure of a patient or an unintended exposure of a foetus occurs, the foetal, organ, skin, and/or effective dose may be estimated from exposure data. When doses are very low, generic values for the examination may be sufficient, but a full assessment of doses to all exposed organs and tissues may sometimes be required. The use of general terminology to describe risks from stochastic effects is recommended rather than the calculation of numerical values, as these are misleading when applied to individuals.

Web-based platform for patient dose surveys in diagnostic and interventional radiology in Bulgaria: Functionality testing and optimisation.

In the period 2013-2016 the National Centre of Radiobiology and Radiation Protection (NCRRP) at the Ministry of Health of Bulgaria has developed a web based platform for performing national patient dose surveys and establishing Diagnostic Reference Levels (DRLs). It is accessible via internet browser, allowing the users to submit data remotely. Electronic questionnaires, specific for radiography, fluoroscopy, image guided interventional procedures, mammography and CT, were provided. Short and clear manuals were added to guide users and minimise human errors. The web-based data collection platform is functional and is currently being used for performing the third national dose survey in Bulgaria, launched in 2016. Data analysis is facilitated due to the standardisation of collected data and their storing. Using the platform, the participating facilities can establish their typical dose levels based on the median value, and compare them to DRLs. A disadvantage of the platform is the need to enter data manually, but it is opened for future upgrades for automatic data harvesting and analysis. Various practical approaches were used to overcome the lack of qualified human resources and insufficient understanding of the DRL and dose tracking concept and to motivate facilities to submit data.

Eye lens exposure to medical staff during endoscopic retrograde cholangiopancreatography.

The paper presents a study of the radiation doses to eye lens of medical staff during endoscopic retrograde cholangiopancreatography (ERCP) procedures performed in a busy gastroenterology department. For each procedure the dose equivalent to the eye, exposure time, dose rate, Kerma Area Product and fluoroscopy time were recorded. Measurements were performed for a period of two months in four main positions of the operating staff, and then extrapolated to estimate annual doses. The fluoroscopy time per ERCP procedure varied between 1.0 min and 28.8 min, with a mean value of 4.6 min. The calculated mean eye dose per procedure varied between 34.9 µSv and 93.3 µSv. The results demonstrated that if eye protection is not used, annual doses to the eye lens of the gastroenterologist performing the procedure and the anesthesiologist can exceed the dose limit of 20 mSv per year.

Radiation exposure to the eye lens of orthopaedic surgeons during various orthopaedic procedures.

The aim of the present study was to assess the radiation dose to the eye lens of orthopaedic surgeons during various orthopaedic procedures and to make efforts to ensure that radiation protection is optimised. The study was performed for Fractura femoris and Fractura cruris procedures performed in orthopaedic operating theatres, as well as for fractures of wrist, ankle and hand/shoulder performed in the emergency trauma room. The highest mean value of the eye lens dose of 47.2 µSv and higher mean fluoroscopy time of 3 min, as well as the corresponding highest maximum values of 77.1 µSv and 5.0 min were observed for the Fractura femoris procedure performed with the Biplanar 500e fluoroscopy systems. At a normal workload, the estimated mean annual dose values do not exceed the annual occupational dose limit for the lens of eye, but at a heavy workload in the department, this dose limit could be achieved or exceeded. The use of protective lead glasses is recommended as they could reduce the radiation exposure of the lens of the eye. The phantom measurements demonstrated that the use of half-dose mode could additionally reduce dose to the operator's eye lens.

EUTEMPE-RX, an EC supported FP7 project for the training and education of medical physics experts in radiology.

The core activity of the medical physics expert (MPE) is to ensure optimal use of ionising radiation in healthcare. It is essential that these healthcare professionals are trained to the highest level, defined as European Qualifications Framework for Lifelong Learning (EQF) level 8 by the European Commission's Radiation Protection Report 174 'Guidelines on the MPE'. The main objective of the EUTEMPE-RX project is to provide a model training scheme that allows the medical physicist in diagnostic and interventional radiology (D&IR) to reach this high level. A European network of partners was brought together in this FP7 EC project to ensure sufficient expertise in all aspects of the subject and to create a harmonised course programme. Targeted participants are medical physicists in D&IR in hospitals, engineers and scientists in medical device industries and officers working in regulatory authorities. Twelve course modules will be developed at EQF level 8, with radiation safety and diagnostic effectiveness being prevalent subjects. The modules will combine online with face-to-face teaching using a blended learning approach.

Dosimetry methods for multi-detector computed tomography.

The aim of this study is to compare four dosimetry methods for wide-beam multi-detector computed tomography (MDCT) in terms of computed tomography dose index free in air (CTDI free-in-air) and CTDI measured in phantom (CTDI phantom). The study was performed with Aquilion One 320-detector row CT (Toshiba), Ingenuity 64-detector row CT (Philips) and Aquilion 64 64-detector row CT (Toshiba). In addition to the standard dosimetry, three other dosimetry methods were also applied. The first method, suggested by International Electrotechnical Commission (IEC) for MDCT, includes free-in-air measurements with a standard 100-mm CT pencil ion chamber, stepped through the X-ray beam, along the z-axis, at intervals equal to its sensitive length. Two cases were studied-with an integration length of 200 mm and with a standard polimetil metakrilat (PMMA) dosimetry phantom. The second approach comprised measurements with a twice-longer phantom and two 100-mm chambers positioned and fixed against each other, forming a detection length of 200 mm. As a third method, phantom measurements were performed to study the real-dose profile along z-axis using thermoluminescent detectors. Fabricated PMMA tube of a total length of 300 mm in cylindrical shape containing LiF detectors was used. CTDI free-in-air measured with an integration length of 300 mm for 160 mm wide beam was by 194 % higher than the same quantity measured using the standard method. For an integration length of 200 mm, the difference was 18 % for 40 mm wide beam and 14 % for 32 mm wide beam in comparison with the standard CTDI measurement. For phantom measurements, the IEC method resulted in difference of 41 % for the beam width 160 mm, 19 % for the beam width 40 mm and 18 % for the beam width 32 mm compared with the method for CTDI vol. CTDI values from direct measurement in the phantom central hole with two chambers differ by 20 % from the calculated values by the IEC method. Dose profile for beam widths of 40, 32 and 16 mm, and analysis and conclusions are presented.

Patient doses from hybrid SPECT-CT procedures.

The aim of this work is to estimate patient doses from hybrid single-photon emission computed tomography (SPECT) and computed tomography (CT) procedures. The study involved all four SPECT-CT systems in Bulgaria. Effective dose was estimated for about 100 patients per system. Ten types of examinations were considered, representing all diagnostic procedures performed in the SPECT-CT systems. Effective doses from the SPECT component were calculated applying the ICRP 53 and ICRP 80 conversion coefficients. Computed tomography dose index and dose length product were retrospectively obtained from the archives of the systems, and effective doses from the CT component were calculated with CT-Expo software. Parallel estimation of CT component contribution with the National Radiological Protection Board (NRPB) conversion coefficients was performed where applicable. Large variations were found in the current practice of SPECT-CT imaging. Optimisation actions and diagnostic reference levels were proposed.

Risk of radiation exposure to medical staff involved in interventional endourology.

The aim is to estimate the possibility the new annual dose limit for eye lens to be exceeded and to study the impact of protective shield. Radiation exposure to medical personnel was evaluated with EDD-30 dosemeter in positions of operating surgeon, assisting doctor and nurse. At the operator's typical position for diagnosis and treatment of the urinary tract, the lens dose rates were 0.9 mSv h(-1) and 0.06 mSv h(-1) without and with lead shield. At the operator's position typical for percutaneous intervention dose rates were 1.9 and 0.02 mSv h(-1), respectively. At typical workload, the annual eye lens dose to the main operator without protective screen was estimated to be 29 mSv. With lead screen, operator lens dose can be reduced by a factor of 15-95 according to the procedure. Installation and use of lead screen and use of lead glasses were recommended to the endourology medical team.

The influence of novel CT reconstruction technique and ECG-gated technique on image quality and patient dose of cardiac computed tomography.

The aim of the present study was to compare image quality and patient dose in cardiac computed tomography angiography (CTA) in terms of volume computed tomography dose index (CTDI vol), dose length product (DLP) and effective dose, when changing from filtered back projection (FBP) to adaptive iterative dose reduction (AIDR) reconstruction techniques. Further aim was to implement prospective electrocardiogram (ECG) gating for patient dose reduction. The study was performed with Aquilion ONE 320-row CT of Toshiba Medical Systems. Analysis of cardiac CT protocols was performed before and after integration of the new software. The AIDR technique showed more than 50 % reduction in CTDIvol values and 57 % in effective dose. The subjective evaluation of clinical images confirmed the adequate image quality acquired by the AIDR technique. The preliminary results indicated significant dose reduction when using prospective ECG gating by keeping the adequate diagnostic quality of clinical images.

A study to establish international diagnostic reference levels for paediatric computed tomography.

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.