Use Of Diagnostic Reference Levels Research Articles

Improving a regional project on diagnostic reference levels for interventional procedures (OPRIPALC) with the support of a dose management system for the protection of patients and staff

Interventional radiology is a clinical practice with important benefits for patients, but which involves high radiation doses. The optimisation of radiation protection (RP) for paediatric interventional cardiology is a priority for both patients and staff. The use of diagnostic reference levels (DRLs) has been proposed by the International Commission on Radiological Protection to improve RP in imaging procedures. Dose management systems (DMSs) allow the automatic collection of dosimetric, geometric and technical data to assist the optimisation process, with a continuous audit of the procedures, generating alerts to implement corrective actions when necessary. Patient dose indicators may be analysed individually and for different radiation events (fluoroscopy and cine runs). Occupational doses per procedure may be analysed (if electronic dosimeters are available) and linked with patient doses for an integrated approach to RP. Regional optimisation programmes require data collection and processing from several countries to set and periodically update the DRLs. Patient data is anonymised, and each participating hospital has access to their data in a central computer server. Using DMSs may be one of the best ways to support these programs in the collection and analysis of data, raising alerts about high patient and occupational doses and suggesting optimisation actions.

Optimization of Radiation Protection in Pediatric Interventional Radiology in Latin America and the Caribbean: Development, Advancements, Challenges and Achievements of the OPRIPALC Program.

This article presents the development, advancements, challenges and achievements of the "Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean" (OPRIPALC) program. This international initiative is led by the World Health Organization, the Pan American Health Organization and the International Atomic Energy Agency. The main objectives of OPRIPALC are to foster a culture of radiological protection in pediatric interventions, enhance these procedures' quality, and define optimization strategies such as the use of diagnostic reference levels (DRLs). Currently, 33 centers from 12 countries participate actively in the program. Significant progress has been made towards the proposed objectives, overcoming the challenges posed by the COVID-19 pandemic. Through many virtual meetings for coordination, planning, training and follow-up, a comprehensive set of DRLs for both diagnostic and therapeutic procedures, categorized by weight and age, have been established and are in use. A consensus document on good practices is in the final stage of development. The program's continuation into at least a second phase is essential to address pending issues, including the integration of automatic dose management systems, the levels of occupational radiation doses, their correlation with pediatric patient doses, and strategies to reduce them.

Actualization of methodology of diagnostic reference levels establishment for interventional radiological procedures

Interventional procedures are accompanied with high levels of patient exposure and even with the possibility of radiation skin damage. That’s why any actions leading to reduction of patients’ exposure levels are of utmost importance. Implementation of diagnostic reference levels is considered to be one of the most successful actions to reduce patient exposure levels. However the basic concept of diagnostic reference levels cannot be used for interventional radiology due to fact that procedures are not standardized. The article studies the main difficulties in applying the standard concept of diagnostic reference levels for interventional radiology procedures and proposes a new concept, taking into account the specifics of these procedures; the domestic and international documents are analyzed. The list of interventional procedures for diagnostic reference levels establishment is suggested based on the statistical data on performed procedures in the Russian Federation. The results of this study were used for the new Russian guidelines “Optimization of radiation protection of patients undergoing medical radiation diagnostic examinations through the use of diagnostic reference levels”.

FIRST CARDIAC COMPUTED TOMOGRAPHY TYPICAL RADIATION DOSE VALUES FROM A SINGLE CENTRE IN NIGERIA: A PILOT STUDY.

Concern regarding radiation dose associated with cardiac computed tomography (CT) still exists and requires the use of diagnostic reference levels for dose optimisation. Typical median doses were established for 58 consented adult patients from a single centre for coronary artery calcium score (CACS) as volume computed tomography dose index (CTDIvol): 5.9mGy; dose length product (DLP): 86.6mGy*cm and cardiac CT angiography (CCTA) as CTDIvol: 11.1mGy; DLP: 190.8mGy*cm. Wide radiation dose variability in terms of CTDIvol was noted for CACS: 2.7-15.9mGy, a 6-fold, whereas for CCTA it ranges from 3.8 to 52.8mGy, a 14-fold. The DLP values for CACS range from 33.2 to 344.2mGy*cm, which is 10-fold, whereas for CCTA it ranges from 32.8 to 834.9mGy*cm, a 25-fold. The typical values compared lower than the radiation dose from other countries; however, the wide variability in dose remains a call for concern.

A European perspective on dental cone beam computed tomography systems with a focus on optimisation utilising diagnostic reference levels

Cone beam computed tomography (CBCT) has been available since the late 1990s for use in dentistry. European legislation requires optimisation of protection and the use of diagnostic reference levels (DRLs) as well as regular quality control (QC) of the imaging devices, which is well outlined in existing international recommendations. Nevertheless, the level of application is not known. Earlier studies have indicated that few European countries have established DRLs and that patient doses (exposure parameters) have not been properly optimised. The EURADOS Working Group 12—Dosimetry in Medical Imaging undertook a survey to identify existing practices in Member States. Questionnaires were developed to identify equipment types, clinical procedures performed, and exposure settings used. The surveys were circulated to 22 countries resulting in 28 responses from 13 countries. Variations were identified in the exposure factors and in the doses delivered to patients for similar clinical indicators. Results confirm that patient doses are still not properly optimised and DRLs are largely not established. There is a need to promote the importance of performing QC testing of dental CBCT equipment and to further optimise patient exposure by establishment and use of DRLs as a part of a continuous optimisation process.

Old enemy, new threat: you can’t solve today’s problems with yesterday’s solution

The radiation protection principles of justification, optimization, and dose limitation as enumerated by the International Commission on Radiological Protection have been guiding light for the profession for over three decades. The dose limitation does not apply to medical exposure but keeping patients’ doses low is achieved through optimization, particularly by developing and using diagnostic reference levels (DRLs). There are new findings that demonstrate that despite using the best possible approaches to justification and optimization including as well use of DRLs, a very large number of patients are receiving doses in excess of 100 mSv of effective dose or organ doses exceeding 100 mGy. A non-ignorable fraction of patients is receiving such high doses in a single day. The magnitude of such patients creates the need for a relook into the principles with the intent to understand what can be done to attend to today’s problems. A look at other areas such as approaches, and principles used in the pharmaceutical industry and in traffic management throws some light into what can be learnt from these examples. It appears that the system needs to be enriched to deal with the protection of the individual patient. The currently available approaches and even the principles are largely based on the protection of the population or group of patients. The third level of justification for individual needs further refinement to take into account series of imaging many patients are needing, and cumulative radiation doses involved, many of which happen in a short duration of 1 to 5 years. There is every likelihood of patient radiation doses continuing to increase further that underscores the need for timely attention. This paper provides several suggestions to deal with the situation.

ESTABLISHING LOCAL AND NATIONAL DIAGNOSTIC AND INTERVENTIONAL CARDIOLOGY AND RADIOLOGY REFERENCE LEVELS IN A SMALL EUROPEAN STATE: THE CASE OF MALTA.

European Directive 2013/59/EURATOM requires the establishment and use of diagnostic reference levels (DRLs) for diagnostic and interventional procedures. The purpose of this study was to establish local DRLs for a major tertiary public hospital. As the hospital is the only such hospital in Malta, the same data collected for setting local DRLs can also be used for setting national DRLs, making local DRLs de facto national DRLs. A retrospective survey of cumulative kerma-area product (KAP) and fluoroscopy time data from the cardiac catheterisation laboratory and interventional radiology suites was carried out. The effect of system upgrades on cumulative KAP was also assessed. Local DRLs were set for common cardiology and interventional radiology procedures. All DRLs compare favourably with those in European literature. A Philips Allura Clarity upgrade to the cardiac catheterisation laboratories led to significant reductions in cumulative KAP (p≪ 0.05) for most procedures.

Consideration of diagnostic reference levels for pediatric chest X-ray examinations.

The use of diagnostic reference levels (DRLs) is currently recommended, and dose evaluation is considered to be important for establishing a Japanese radiological protection system in radiological medicine. Children, in particular, are sensitive to radiation, and their exposure levels must be taken into account. The DRL for the entrance surface dose (ESD) used in pediatric chest X-ray examinations in Japan is 0.2mGy. However, the bodies of infants and young children show major changes with rapidly developing organs. Thus, the possibility that organ development may also be affected by radiation exposure should be taken into account. Therefore, radiological technologists must be conservative in setting radiographic conditions for pediatric examinations. The objective of this study was to evaluate the doses used in pediatric chest X-ray examinations at our hospital and compare them with the current DRLs, considering the assumption that setting conditions individually for different ages and subject thicknesses and performing more detailed dose evaluations will help reduce radiation exposure. The study was carried out to estimate the ESDs in 163 pediatric patients who underwent frontal or lateral chest X-ray examinations at our hospital. All doses were lower than 0.2mGy, the dose recommended in the Japanese DRLs 2015. The doses showed a strong correlation with age, but a weaker correlation with subject thickness. These results suggest that instead of considering a common DRL for all children, the DRL should be evaluated on the basis of age.

Practical recommendations for the application of DE 59/2013.

The changes introduced with Council Directive 2013/59/Euratom will require European Member States adapt their regulations, procedures and equipment to the new high standards of radiation safety. These new requirements will have an impact, in particular, on the radiology community (including medical physics experts) and on industry. Relevant changes include new definitions, a new dose limit for the eye lens, non-medical imaging exposures, procedures in asymptomatic individuals, the use and regular review of diagnostic reference levels (including interventional procedures), dosimetric information in imaging systems and its transfer to the examination report, new requirements on responsibilities, the registry and analysis of accidental or unintended exposure and population dose evaluation (based on age and gender distribution). Furthermore, the Directive emphasises the need for justification of medical exposure (including asymptomatic individuals), introduces requirements concerning patient information and strengthens those for recording and reporting doses from radiological procedures, the use of diagnostic reference levels, the availability of dose-indicating devices and the improved role and support of the medical physics experts in imaging.

Measurement of patient skin dose and establishment of local diagnostic reference levels for interventional cardiology procedures

Use of diagnostic reference levels (DRLs) is an important tool for patient dose optimization in interventional radiology. DRLs are normally expressed in terms of kerma-area product (Pka). However, no direct method is available to estimate the probability of skin reactions using system displayed quantities. The aim of this work was to measure skin entrance doses (SEDs) in patients undergoing coronary angiography (CA) and percutaneous coronary interventions (PCI) using Gafchromic films and establish DRLs. The details of patients, exposure parameters, and dose quantities were recorded for 572 patients. Out of these, skin doses were measured for selected 64 patients using Gafchromic film. Measured SEDs are in the range of 48.2–740 mGy and 84–1242 mGy for CA and PCI, respectively. The data of 572 patients were analyzed, and 75th percentile of Pkawas calculated. DRLs for CA and PCI in terms of Pkaare found to be 34 and 134 Gy.cm2, respectively. DRLs for CA and PCI in terms of cumulative air kerma (Ka) at reference point are found to be 590 mGy and 1930 mGy, respectively. SED has a good correlation with Ka, however, it does not correlate well with Pka.

OA098] Patient dose monitoring in interventional radiology

Purpose In light of ICRP recommendations and new European BSS that strengthen requirements concerning patient dose recording and reporting and the use of diagnostic reference levels (DRL), dose indicators were collected from a sample of subjects undergoing different type of interventional procedures, using a commercial Dose Archiving Communication System (DACS) software, directly communicating with the imaging modality, Philips XperFD20. This abstract presents preliminary results of six months of survey. Materials and Methods 400 patients were monitored. The procedures were grouped in 7 subset (N is the number subjects): 1-Embolization (N = 228); 2-Varicocele sclerosing treatment (N = 30); 3-Biliary intervention (N = 95); 4-HUPG Hepatic vein portosystemic gradient (N = 25); 5-TIPS (N = 12); 6-Portal Venography (N = 5); 7-Angioplasty (N = 5). Mean values, range, 50th and 75th percentile of the distribution were estimated for KAP (Kerma Area Product) that is a global index, fluoroscopy time FT and cumulative air Kerma (CK) at IRP (Intervention Reference Point), being the last quantity an indicator of the skin dose. Results Mean value (and 75° percentile) for KAP (expressed in cGy* cm 2 ), for the 7 procedures, were respectively: Procedure 1: 38855 (61866); Procedure 2: 1522 (1831); Procedure 3: 4696 (6983); Procedure 4: 15940 (22854); Procedure 5: 33244(36973); Procedure 6: 15516 (24988); Procedure 7: 11796 (6333). FT ranged from a few minutes to above 1 hour, with the mean value for the whole set of data being 11 min. The skin dose index CK exceeded the threshold values of 2-3-4-5 Gy in 7.8-2.4-1.1 and 0.4% of cases respectively. Conclusions Data are comparable with those reported by other authors and consistent with published DRL, with a wide variability due to different degrees of procedure complexity. Further data need to be collected in order to define our own DRL. The threshold values for manifestation of deterministic effects were passed in a relatively small fraction of cases, for which follow up is indicated [1] , [2] , [3] .

The mandate and work of ICRP Committee 3 on radiological protection in medicine.

The mandate of Committee 3 of the International Commission on Radiological Protection (ICRP) is concerned with the protection of persons and unborn children when ionising radiation is used in medical diagnosis, therapy, and biomedical research. Protection in veterinary medicine has been newly added to the mandate. Committee 3 develops recommendations and guidance in these areas. The most recent documents published by ICRP that relate to radiological protection in medicine are 'Radiological protection in cone beam computed tomography' (ICRP Publication 129) and 'Radiological protection in ion beam radiotherapy' (ICRP Publication 127). A report in cooperation with ICRP Committee 2 entitled 'Radiation dose to patients from radiopharmaceuticals: a compendium of current information related to frequently used substances' (ICRP Publication 128) has also been published. 'Diagnostic reference levels in medical imaging' (ICRP Publication 135), published in 2017, provides specific advice on the setting and use of diagnostic reference levels for diagnostic and interventional radiology, digital imaging, computed tomography, nuclear medicine, paediatrics, and multi-modality procedures. 'Occupational radiological protection in interventional procedures' was published in March 2018 as ICRP Publication 139. A document on radiological protection in therapy with radiopharmaceuticals is likely to be published in 2018. Work is in progress on several other topics, including appropriate use of effective dose in collaboration with the other ICRP committees, guidance for occupational radiological protection in brachytherapy, justification in medical imaging, and radiation doses to patients from radiopharmaceuticals (an update to ICRP Publication 128). Committee 3 is also considering the development of guidance on radiological protection in medicine related to individual radiosusceptibility, in collaboration with ICRP Committee 1.

Patient dose monitoring and the use of diagnostic reference levels for the optimization of protection in medical imaging: current status and challenges worldwide.

Optimization is one of the key concepts of radiation protection in medical imaging. In practice, it involves compromising between the image quality and dose to the patient; the dose should not be higher than necessary to achieve an image quality (or diagnostic information) needed for the clinical task. Monitoring patient dose is a key requirement toward optimization. The concept of diagnostic reference level (DRL) was introduced by the International Commission on Radiological Protection as a practical tool for optimization. Unfortunately, this concept has not been applied consistently worldwide. To review the current strengths and weaknesses worldwide and to promote improvements, the International Atomic Energy Agency organized a Technical Meeting on patient dose monitoring and the use of DRLs on May 2016. This paper reports a summary of the findings and conclusions from the meeting. The strengths and weaknesses were generally different in less-developed countries compared with developed countries. Possible improvements were suggested in six areas: human resources and responsibilities, training, safety and quality culture, regulations, funding, and tools and methods. An overall conclusion was that radiation protection requires a patient-centric approach and a transfer from purely reactive to increasingly proactive optimization, whereby the best outcome is expected from good teamwork.

Establishing and monitoring DRLS

Diagnostic Reference Levels (DRLs) have proven to be an effective tool for dose optimisation of protection in medical imaging. The ‘Euratom Basic Safety Standards’ states that ‘Member States shall ensure the establishment, regular review and use of diagnostic reference levels for radiodiagnostic examinations, having regard to the recommended European diagnostic reference levels where available, and when appropriate, for interventional radiology procedures, and the availability of guidance for this purpose’. The ‘European DRLs for Paediatric Imaging’ project (abbreviation: PiDRL) has very recently developed European Guidelines on how to establish and how to use paediatric DRLs. DRLs should be established primarily for examinations that significantly contribute to the collective effective dose of the patient population. DRLs should be based on appropriate patient dose surveys. In general, it is recommended that from each institution a representative sample of at least 10 patients per procedure type and per patient group is needed for non-complex examinations such as radiography and CT and at least 20 patients per procedure type for complex procedures such as fluoroscopy and fluoroscopically guided procedures. For all body examinations, weight should be used as a parameter for patient grouping. Patient dose data should be collected from a representative sample of various types of equipment and practices in the geographical area concerned. Dose management solutions can play a very important role in the establishment and use of DRLs.

Diagnostic reference levels and complexity indices in interventional radiology: a national programme.

To propose national diagnostic reference levels (DRLs) for interventional radiology and to evaluate the impact of the procedural complexity on patient doses. Eight interventional radiology units from Spanish hospitals were involved in this project. The participants agreed to undergo common quality control procedures for X-ray systems. Kerma area product (KAP) was collected from a sample of 1,649 procedures. A consensus document established the criteria to evaluate the complexity of seven types of procedures. DRLs were set as the 3rd quartile of KAP values. The KAP (3rd quartile) in Gy cm2 for the procedures included in the survey were: lower extremity arteriography (n = 784) 78; renal arteriography (n = 37) 107; transjugular hepatic biopsies (THB) (n = 30) 45; biliary drainage (BD) (n = 314) 30; uterine fibroid embolization (UFE) (n = 56) 214; colon endoprostheses (CE) (n = 31) 169; hepatic chemoembolization (HC) (n = 269) 303; femoropopliteal revascularization (FR) (n = 62) 119; and iliac stent (n = 66) 170. The complexity involved the increases in the following KAP factors from simple to complex procedures: THB x4; BD x13; UFE x3; CE x3; HC x5; FR x5 and IS x4. The evaluation of the procedure complexity in patient doses will allow the proper use of DRLs for the optimization of interventional radiology. • National DRLs for interventional procedures have been proposed given level of complexity • For clinical audits, the level of complexity should be taken into account. • An evaluation of the complexity levels of the procedure should be made.

Dose management in conventional nuclear medicine imaging and PET

This review of the basic concepts of dose management in conventional nuclear medicine imaging and positron emission tomography focuses on methods for dose assessment, difficulties with image quality evaluation, need for clear image quality criteria and observer performance studies, studies on representative groups of patients contra individual patients, clinically applicable methods for dose reduction, including the use of diagnostic reference levels. The dose management in nuclear imaging requires more attention and there is a need for better contribution of new technology for individual patient dose management as well as for education and training of the multidisciplinary teams of nuclear medicine physicians, technologists and medical physicists, responsible for the investigations.

Summary of the European Directive 2013/59/Euratom: essentials for health professionals in radiology.

The aspects of the new European Directive 2013/59/Euratom most relevant to diagnostic imaging and intervention are summarised. The Directive, laying down basic safety standards for protection against the dangers from exposure to ionising radiation, emphasises the need for justification of medical exposure (including asymptomatic individuals), introduces requirements concerning patient information and strengthens those for recording and reporting doses from radiological procedures, the use of diagnostic reference levels, the availability of dose-indicating devices and the improved role and support of the Medical Physics Experts in imaging. Relevant changes include new definitions, a new dose limit for the eye lens, non-medical imaging exposures, procedures in asymptomatic individuals, the use and regular review of diagnostic reference levels (including interventional procedures), dosimetric information in imaging systems and its transfer to the examination report, new requirements on responsibilities, the registry and analysis of accidental or unintended exposure and population dose evaluation (based on age and gender distribution). These changes will require Member States, the radiology community and the industry to adapt regulations, practices and equipment for a high standard of radiation safety. By 6 February 2018, the Directive has to be transposed into the national legislation of the Member States of the European Union.Main messages• The new European Basic Safety Standards Directive impacts radiology departments• Changes in justification, patient information, responsibilities and dose reporting are most significant• Diagnostic reference levels and the role of medical physics experts are clarified• Dose limits to the eye lens are lower than in the previous directive• Responsibilities in radiation safety have been defined

Basis for standards: ICRP activities.

The purpose of this chapter is to describe work achieved recently by the International Commission on Radiological Protection (ICRP) and especially by Committee 3 (Protection in Medicine) and its use for standards. In March 1960, the Board of Governors of the International Atomic Energy Agency approved the Agency's 'Health and Safety Measures', stating that the Agency's 'Basic Safety Standards' (BSS) would be based, to the extent possible, on the recommendations of the ICRP. In a similar way, the Council of the European Union took into account the new recommendations of the ICRP when adopting the new Directive 2013/59/EURATOM that laid down BSS for protection against the dangers arising from exposure to ionising radiation. The new limit for the lens of the eyes for occupational exposures has been incorporated into these international standards and several articles dealing with medical exposures: justification, optimisation, recording patient doses, the use of diagnostic reference levels, training, accidental and unintended exposures, etc. have also been included in agreement with the ICRP recommendations.

Radiation doses in computed tomography: Need for optimization and application of dose reference levels in Nigeria

Background: Establishment and use of diagnostic reference levels (DRLs) is essential for proper use and audit of ionizing radiation in medicine and other radiation applications. Nigeria does not yet have a guideline for DRL. The European Commission reference dose levels were applied to routine computed tomography (CT) examinations in Nigeria's major hospitals. Aim: To determine the dose of CT examinations at the University College Hospital, Ibadan, Nigeria and provide a template for dose optimization. Materials and Methods: Data were obtained from a GE Brightspeed multidetector CT scanner. The dose characteristics and estimates were derived from computed tomography dose index (CTDI vol ), and dose length product (DLP) with the effective dose (E) calculated using software developed by ImPACTscan group with the National Radiological Protection Board-S250 conversion coefficients data for a random sampling of 1 per 10 typical CT patients. Results: The mean values of CTDI vol in mGy were 73.5 ± 4.2 (head), 22.7 ± 6.7 (chest), 37.9 ± 5.6 (abdomen), 28.2 ± 8.3 (abdomen-pelvis), 41.4 ± 13.2 (cervical spine), and 40.1 ± 4.2 (lumbar spine) examinations. The corresponding mean values of DLP in mGy.cm were 1898, 1189, 1902, 2548, 1372, and 1563, respectively. The calculated E values in mSv for the above examinations were 2.8, 11.8, 22.5, 39.6, 4.6, and 29.0, respectively. All values consistently exceeded recommended ECRDLs except the CTDI vol for chest, cervical, and abdomen-pelvis examinations. Conclusion: CT doses were higher than EC recommended guidelines necessitating a need for optimization of CT practice and the requirement for a CT dose survey in Nigeria.

Radiation dose to premature new-borns in the Belgian neonatal intensive care units

In the neonatal intensive care units (NICU), premature new-borns may be exposed to important doses. Because of their increased radiosensitivity and longer life expectancy, dose optimisation is of importance. The present study aimed at evaluating the dose of the most common radiographs in the Belgian NICU. Entrance surface kerma (ESK) and kerma area product (KAP) were collected in 17 NICU (among 19 in Belgium). Median ESK ranged from 13 to 172 µGy and from 8 to 117 µGy for chest and combined chest-abdomen radiographs, respectively; median KAP ranged from 1.4 to 14.2 mGy cm(2) and from 3.8 to 28.1 mGy cm(2) for chest and combined chest-abdomen radiographs, respectively. Those differences were due to large variations in the examination settings. Diagnostic reference levels (DRL) were set for chest and combined chest-abdomen radiographs. Though the radiograph dose was usually low, the cumulative dose per stay could be high. The wide, intercentre differences indicate that there is scope for dose reduction. The use of DRL should contribute to achieve this object.