Recurrent medical imaging exposures for the care of patients: one way forward

Medical imaging is both valuable and essential in the care of patients. Much of this imaging depends on ionizing radiation with attendant responsibilities for judicious use when performing an examination. This responsibility applies in settings of both individual as well as multiple (recurrent) imaging with associated repeated radiation exposures. In addressing the roles and responsibilities of the medical communities in the paradigm of recurrent imaging, both the International Atomic Energy Agency (IAEA) and the American Association of Physicists in Medicine (AAPM) have issued position statements, each affirmed by other organizations. The apparent difference in focus and approach has resulted in a lack of clarity and continued debate. Aiming towards a coherent approach in dealing with radiation exposure in recurrent imaging, the IAEA convened a panel of experts, the purpose of which was to identify common ground and reconcile divergent perspectives. The effort has led to clarifying recommendations for radiation exposure aspects of recurrent imaging, including the relevance of patient agency and the provider-patient covenant in clinical decision-making. CLINICAL RELEVANCE STATEMENT: An increasing awareness, generating some lack of clarity and divergence in perspectives, with patients receiving relatively high radiation doses (e.g., ≥ 100 mSv) from recurrent imaging warrants a multi-stakeholder accord for the benefit of patients, providers, and the imaging community. KEY POINTS: • Recurrent medical imaging can result in an accumulation of exposures which exceeds 100 milli Sieverts. • Professional organizations have different perspectives on roles and responsibilities for recurrent imaging. • An expert panel reconciles differing perspectives for addressing radiation exposure from recurrent medical imaging.

Safety in radiation oncology (SAFRON): Learning about incident causes and safety barriers in external beam radiotherapy

PURPOSE

Safety in Radiation Oncology (SAFRON) is a reporting and learning system on radiotherapy and radionuclide therapy incidents and near misses. The primary aim of this paper is to examine whether any discernible patterns exist in the causes of reported incidents and safety barriers within the SAFRON system concerning external beam radiotherapy.

METHODS AND MATERIALS

This study focuses on external beam radiotherapy incidents, reviewing 1685 reports since the inception of SAFRON until December 2021. Reports that did not identify causes of incidents and safety barriers were excluded from the final study population.

RESULTS

Simple two-dimensional radiotherapy or electron beam therapy were represented by 97 reports, three-dimensional conformal radiotherapy by 39 reports, modulated arc therapy by 12 reports, intensity modulated radiation therapy by 11 reports, stereotactic radiosurgery by 4 reports, and radiotherapy with protons or other particles by 1 report, while for 92 of them, no information on treatment method had been provided. Most of the reported incidents were minor incidents and were discovered by the radiation therapist. Inadequate direction/information in staff communication was the most frequently reported cause of incident, and regular independent chart check was the most common safety barrier.

CONCLUSIONS

The results indicate that the majority of incidents were reported by radiation therapists, and the majority of these incidents were classified as minor. Communication problems and failure to follow standards/procedures/practices were the most frequent causes of incidents. Furthermore, regular independent chart checking was the most frequently identified safety barrier.

Availability of technology for managing cancer patients in the Southeast European (SEE) region

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Gap of public on-the-ground cancer data was addressed through questionnaires to professionals in the SEE region.

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There is a lack of diagnostic imaging and radiotherapy modalities in the SEE region in comparison to Western Europe.

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The Mortality to incidence ratio correlates inversely with the economic development and the availability of radiotherapy equipment.

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The cancer incidence in SEE countries was correlate directly with the life expectancy and the availability of diagnostic equipment.

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The need for reliable national and regional cancer registries in SEE countries for data collection and analysis has been emphasized.

Background

The Southeast European (SEE) region of 10 countries and about 43 million people differs from Western Europe in that most SEE countries lack active cancer registries and have fewer diagnostic imaging devices and radiotherapy (RT) units. The main objective of this research is to initiate a common platform for gathering SEE regional cancer data from the ground up to help these countries develop common cancer management strategies.

Methods

To obtain detailed on-the-ground information, we developed separate questionnaires for two SEE groups: a) ONCO - oncologists regarding cancer treatment modalities and the availability of diagnostic imaging and radiotherapy equipment; and b) REG - national radiation protection and safety regulatory bodies regarding diagnostic imaging and radiotherapy equipment in SEE facilities.

Results

Based on responses from 13/17 ONCO participants (at least one from each country) and from 9/10 REG participants (all countries but Albania), cancer incidence rates are higher in those SEE countries that have greater access to diagnostic imaging equipment while cancer mortality-to-incidence (MIR) ratios are higher in countries that lack radiotherapy equipment.

Conclusion

By combining unique SEE region information with data available from major global databases, we demonstrated that the availability of diagnostic imaging and radiotherapy equipment in the SEE countries is related to their economic development. While immediate diagnostic imaging and radiation therapy capacity building is necessary, it is also essential to develop both national and SEE-regional cancer registries in order to understand the heterogeneity of each country’s needs and to establish regional collaborative strategies for combating cancer.

Patients With Cancer in the Countries of South-East Europe (the Balkans) Region and Prospective of the Particle Therapy Center: South-East European International Institute for Sustainable Technologies (SEEIIST)

PURPOSE

A recent initiative was launched for establishing the South-East European International Institute for Sustainable Technologies (SEEIIST), which will provide a cutting-edge Hadron radiation therapy treatment and research institute for treating cancer patients with Hadron therapy (HT). To justify the initiative for building the SEEIIST facility, a study was conducted to estimate the number of patients with cancer from the SEE region that would be eligible for HT.

METHODS AND MATERIALS

Two different methods for projecting the future annual cancer incidence have been applied: (1) using the International Agency on Research on Cancer@World Health Organization's (WHO) Globocan model which uses country's demographic factors, and (2) averaging the crude incidence data of 3 SEE countries with available national cancer registries, using a linear regression model of combined incidence per 100,000, and applying it to the entire SEE region. Cancer epidemiology data were collected and studied by using the countries' cancer datasheets from WHO. The top 10 cancers were presented for the SEE region. Studies of other countries were used to develop a primordial model for estimating the number of SEE patients who could be treated most successfully with HT upon SEEIIST commissioning in 2030.

RESULTS

A model was developed to estimate the number of eligible patients for HT from SEE. It is estimated that 2900 to 3200 patients per year would be eligible for HT in the new SEEIIST facility in 2030.

CONCLUSIONS

After commissioning, SEEIIST will initially treat approximately 400 patients per year, progressing toward 1000. Creation of SEEIIST dedicated patient selection criteria will be both necessary and highly challenging.

Variations in CT Utilization, Protocols, and Radiation Doses in COVID-19 Pneumonia: Results from 28 Countries in the IAEA Study

Background

There is lack of guidance on specific CT protocols for imaging patients with coronavirus disease 2019 (COVID-19) pneumonia.

Purpose

To assess international variations in CT utilization, protocols, and radiation doses in patients with COVID-19 pneumonia.

Materials and Methods

In this retrospective data collection study, the International Atomic Energy Agency (IAEA) coordinated a survey between May and July 2020 regarding CT utilization, protocols, and radiation doses from 62 healthcare sites in 34 countries across five continents for CT exams performed in COVID-19 pneumonia. The questionnaire obtained information on local prevalence, method of diagnosis, most frequent imaging, indications for CT, and specific policies on use of CT in COVID-19 pneumonia. Collected data included general information (patient age, weight, clinical indication), CT equipment (CT make and model, year of installation, number of detector rows), scan protocols (body region, scan phases, tube current and potential), and radiation dose descriptors (CT dose index (CTDI_vol) and dose length product (DLP)). Descriptive statistics and generalized estimating equations were performed.

Results

Data from 782 patients (median age (interquartile range) of 59(15) years) from 54 healthcare sites in 28 countries were evaluated. Less than one-half of the healthcare sites used CT for initial diagnosis of COVID-19 pneumonia and three-fourth used CT for assessing disease severity. CTDI_vol varied based on CT vendors (7-11mGy, p<0.001), number of detector-rows (8-9mGy, p<0.001), year of CT installation (7-10mGy, p=0.006), and reconstruction techniques (7-10mGy, p=0.03). Multiphase chest CT exams performed in 20% of sites (11 of 54) were associated with higher DLP compared with single-phase chest CT exams performed in 80% (43 of 54 sites) (p=0.008).

Conclusion

CT use, scan protocols, and radiation doses in patients with COVID-19 pneumonia showed wide variation across healthcare sites within the same and different countries. Many patients were scanned multiple times and/or with multiphase CT scan protocols.

See also the editorial by Lee.

IAEA survey of dental cone beam computed tomography practice and related patient exposure in nine Central and Eastern European countries

OBJECTIVES

Cone beam CT (CBCT) in dentistry and maxillofacial surgery is a widely used imaging method for the assessment of various maxillofacial and dental pathological conditions. The objective of this study was to summarize the results of a multinational retrospective-prospective study that focused on patient exposure in this modality.

METHODS

The study included 27 CBCT units and 325 adult and paediatric patients, in total. Data on patients, clinical indications, technical parameters of exposure, patient dose indicator, or, alternatively, dose to phantom were collected. The dose indicator used was air kerma-area product, P_KA.

RESULTS

In most scanners operators are offered with a variety of options regarding technical parameters, especially the field of view size. The median and the third quartile value of P_KA for adult patients in 14 different facilities were 820 mGy cm² and 1000 mGy cm² (interquartile range = 1058 mGy cm²), and 653 mGy cm² and 740 mGy cm² (interquartile range = 1179 mGy cm²) for children, as reported by four different institutions. Phantom dose data were reported from 15 institutions, and median P_KA ranged from 125 mGy cm² to 1951 mGy cm². Median P_KA values varied by more than a 10-fold between institutions, mainly due to differences in imaging protocol used, in particular field of view and tube current-exposure time product.

CONCLUSIONS

The results emphasize the need for a cautious approach to using dental CBCT. Imaging only when the clinical indications are clear, accompanied with the appropriate radiographic techniques and the optimum imaging protocol, will help reduce radiation dose to patients.

Improvement of early detection of breast cancer through collaborative multi-country efforts: Observational clinical study

AIM

The aim of this paper is to present baseline imaging data and the improvement that was achieved by the participating centers after applying practice-specific interventions that were identified during the course of a multicentric multinational research coordinated project.

INTRODUCTION

The incidence and mortality rates from breast cancer are rising worldwide and particularly rapidly across the countries with limited resources. Due to lack of awareness and screening options it is usually detected at a later stage. Breast cancer screening programs and even clinical services on breast cancer have been neglected in such countries particularly due to lack of available equipment, funds, organizational structure and quality criteria.

MATERIALS AND METHODS

A harmonized form was designed in order to facilitate uniformity of data collection. Baseline data such as type of equipment, number of exams, type and number of biopsy procedures, stage of cancer at detection were collected from 10 centers (9 countries: Bosnia-Herzegovina, Costa Rica, Egypt, India, North Macedonia, Pakistan, Slovenia, Turkey, Uganda) were collected. Local practices were evaluated for good practice and specific interventions such as training of professionals and quality assurance programs were identified. The centers were asked to recapture the data after a 2-year period to identify the impact of the interventions.

RESULTS

The data showed increase in the number of training of relevant professionals, positive changes in the mammography practice and image guided interventions. All the centers achieved higher levels of success in the implementation of the quality assurance procedures.

CONCLUSION

The study has encountered different levels of breast imaging practice in terms of expertise, financial and human resources, infrastructure and awareness. The most common challenges were the lack of appropriate quality assurance programs and lack of trained skilled personnel and lack of high-quality equipment. The project was able to create higher levels of breast cancer awareness, collaboration amongst participating centers and professionals. It also improved quality, capability and expertise in breast imaging particularly in centers involved diagnostic imaging.

Quality control in cone-beam computed tomography (CBCT) EFOMP-ESTRO-IAEA protocol (summary report)

The aim of the guideline presented in this article is to unify the test parameters for image quality evaluation and radiation output in all types of cone-beam computed tomography (CBCT) systems. The applications of CBCT spread over dental and interventional radiology, guided surgery and radiotherapy. The chosen tests provide the means to objectively evaluate the performance and monitor the constancy of the imaging chain. Experience from all involved associations has been collected to achieve a consensus that is rigorous and helpful for the practice. The guideline recommends to assess image quality in terms of uniformity, geometrical precision, voxel density values (or Hounsfield units where available), noise, low contrast resolution and spatial resolution measurements. These tests usually require the use of a phantom and evaluation software. Radiation output can be determined with a kerma-area product meter attached to the tube case. Alternatively, a solid state dosimeter attached to the flat panel and a simple geometric relationship can be used to calculate the dose to the isocentre. Summary tables including action levels and recommended frequencies for each test, as well as relevant references, are provided. If the radiation output or image quality deviates from expected values, or exceeds documented action levels for a given system, a more in depth system analysis (using conventional tests) and corrective maintenance work may be required.

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.

IAEA survey of paediatric computed tomography practice in 40 countries in Asia, Europe, Latin America and Africa: procedures and protocols

OBJECTIVE

To survey procedures and protocols in paediatric computed tomography (CT) in 40 less resourced countries.

METHODS

Under a project of the International Atomic Energy Agency, 146 CT facilities in 40 countries of Africa, Asia, Europe and Latin America responded to an electronic survey of CT technology, exposure parameters, CT protocols and doses.

RESULTS

Modern MDCT systems are available in 77 % of the facilities surveyed with dedicated paediatric CT protocols available in 94 %. However, protocols for some age groups were unavailable in around 50 % of the facilities surveyed. Indication-based protocols were used in 57 % of facilities. Estimates of radiation dose using CTDI or DLP from standard CT protocols demonstrated wide variation up to a factor of 100. CTDI(vol) values for the head and chest were between two and five times those for an adult at some sites. Sedation and use of shielding were frequently reported; immobilisation was not. Records of exposure factors were kept at 49 % of sites.

CONCLUSION

There is significant potential for improvement in CT practice and protocol use for children in less resourced countries. Dose estimates for young children varied widely. This survey provides critical baseline data for ongoing quality improvement efforts by the IAEA.

Performance of mammography equipment in the Macedonian breast screening campaign 2008/2009

Breast screening campaign in Macedonia started in the end of 2007 and 19 national mammography departments were included. Contrary to the European Guidelines for Quality Assurance in Mammography Screening, the quality assurance activities were not implemented before the start of the campaign, except at the University Clinic of Radiology, Skopje. The quality control tests were performed for the very first time at 13 mammography units under a licence-obtaining procedure. One of the machines was suspended from clinical and screening practice due to heavy malfunction of the generator, X-ray tube and automatic exposure control (AEC) system. Only 3 of the 13 mammography machines met the criteria for tube voltage (kV) accuracy. Two of the seven AEC systems were calibrated in the optimal optical density (OD) range (OD >1.4). AEC settings corresponded to the recommendations at eight units, while nine units met basic overall image quality criteria. Mean glandular dose (MGD) was higher than the recommended level of 2.5 mGy in four departments. Mean gradient of the film G(0.25-2.0) was below 2.8 at four units. Only two light boxes had a luminance of >1700 cd m(-2) and six rooms had an ambient light level of <50 lx. The findings of this work clearly suggest that the performance of the mammography equipment involved in the campaign in almost 50 % do not supply basic quality criteria for a breast screening programme.

Image quality and dose in mammography in 17 countries in Africa, Asia and Eastern Europe: results from IAEA projects

PURPOSE

The objective is to study mammography practice from an optimisation point of view by assessing the impact of simple and immediately implementable corrective actions on image quality.

MATERIALS AND METHODS

This prospective multinational study included 54 mammography units in 17 countries. More than 21,000 mammography images were evaluated using a three-level image quality scoring system. Following initial assessment, appropriate corrective actions were implemented and image quality was re-assessed in 24 units.

RESULTS

The fraction of images that were considered acceptable without any remark in the first phase (before the implementation of corrective actions) was 70% and 75% for cranio-caudal and medio-lateral oblique projections, respectively. The main causes for poor image quality before corrective actions were related to film processing, damaged or scratched image receptors, or film-screen combinations that are not spectrally matched, inappropriate radiographic techniques and lack of training. Average glandular dose to a standard breast was 1.5 mGy (mean and range 0.59-3.2 mGy). After optimisation the frequency of poor quality images decreased, but the relative contributions of the various causes remained similar. Image quality improvements following appropriate corrective actions were up to 50 percentage points in some facilities.

CONCLUSIONS

Poor image quality is a major source of unnecessary radiation dose to the breast. An increased awareness of good quality mammograms is of particular importance for countries that are moving towards introduction of population-based screening programmes. The study demonstrated how simple and low-cost measures can be a valuable tool in improving of image quality in mammography.

Paediatric CT examinations in 19 developing countries: frequency and radiation dose

The aims of this study were to investigate the frequency of computed tomography (CT) examinations for paediatric patients below 15 y of age in 128 CT facilities in 28 developing countries of Africa, Asia and Eastern Europe and to assess the magnitude of CT doses. Radiation dose data were available from 101 CT facilities in 19 countries. The dose assessment was performed in terms of weighted CT dose index (CTDI(w)), volume CT index and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. The results show that on average the frequency of paediatric CT examinations was 20, 16 and 5 % of all CT examinations in participating centres in Africa, Asia and Eastern Europe, respectively. Eleven CT facilities in six countries were found to use adult CT exposure parameters for paediatric patients, thus indicating limited awareness and the need for optimisation. CT images were of adequate quality for diagnosis. The CTDI(w) variations ranged up to a factor of 55 (Africa), 16.3 (Asia) and 6.6 (Eastern Europe). The corresponding DLP variations ranged by a factor of 10, 20 and 8, respectively. Generally, the CTDI(w) and DLP values in Japan are lower than the corresponding values in the three regions in this study. The study has indicated a stronger need in many developing countries to justify CT examinations in children and their optimisation. Awareness, training and monitoring of radiation doses is needed as a way forwards.

Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects

The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs. The resulting CT images were of adequate quality for diagnosis. The CTDIw and DLP data presented herein are largely similar to those from two recent national surveys. The study has shown a stronger need to create awareness and training of radiology personnel as well as monitoring of radiation doses in many developing countries so as to conform to the ALARA principle.