Cumulative radiation dose estimates from medical imaging in paediatric patients with non-oncologic chronic illnesses. A systematic review

Expert panel on monitoring radiation doses from recurrent medical diagnostic procedures: Sixth Gilbert W. Beebe Webinar

Recurrent imaging is an essential tool for patient care but with an attendant dose from radiation exposure. Recurrent imaging has been the subject of increasing scrutiny and debate based largely on the risk from increasing cumulative doses. However, the accountability for and actions with recurrent imaging as a special component in the general construct of radiation protection in medicine is unclear. This is demonstrated by the perspectives provided by the various imaging community experts. Some perspectives may be different, but many share a common ground. Understanding these various perspectives illustrates the wide-ranging optics in considering benefits and costs in the recurrent imaging paradigm and, moreover, the value in pursuing multi-stakeholder-derived harmonization for recurrent imaging and radiation dose. This move towards consensus would be to the benefit of the imaging community, referrers, and other related healthcare professionals, as well as patients, their caregivers, and the public.

Use of ionizing radiation in a Norwegian cohort of children with congenital heart disease: imaging frequency and radiation dose for the Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) study

BACKGROUND

The European-funded Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) project is a multicenter cohort study assessing the long-term effects of ionizing radiation in patients with congenital heart disease. Knowledge is lacking regarding the use of ionizing radiation from sources other than cardiac catheterization in this cohort.

OBJECTIVE

This study aims to assess imaging frequency and radiation dose (excluding cardiac catheterization) to patients from a single center participating in the Norwegian HARMONIC project.

MATERIALS AND METHODS

Between 2000 and 2020, we recruited 3,609 patients treated for congenital heart disease (age < 18 years), with 33,768 examinations categorized by modality and body region. Data were retrieved from the radiology information system. Effective doses were estimated using International Commission on Radiological Protection Publication 60 conversion factors, and the analysis was stratified into six age categories: newborn; 1 year, 5 years, 10 years, 15 years, and late adolescence.

RESULTS

The examination distribution was as follows: 91.0% conventional radiography, 4.0% computed tomography (CT), 3.6% diagnostic fluoroscopy, 1.2% nuclear medicine, and 0.3% noncardiac intervention. In the newborn to 15 years age categories, 4-12% had ≥ ten conventional radiography studies, 1-8% underwent CT, and 0.3-2.5% received nuclear medicine examinations. The median effective dose ranged from 0.008-0.02 mSv and from 0.76-3.47 mSv for thoracic conventional radiography and thoracic CT, respectively. The total effective dose burden from thoracic conventional radiography ranged between 28-65% of the dose burden from thoracic CT in various age categories (40% for all ages combined). The median effective dose for nuclear medicine lung perfusion was 0.6-0.86 mSv and for gastrointestinal fluoroscopy 0.17-0.27 mSv. Because of their low frequency, these procedures contributed less to the total effective dose than thoracic radiography.

CONCLUSION

This study shows that CT made the largest contribution to the radiation dose from imaging (excluding cardiac intervention). However, although the dose per conventional radiograph was low, the large number of examinations resulted in a substantial total effective dose. Therefore, it is important to consider the frequency of conventional radiography while calculating cumulative dose for individuals. The findings of this study will help the HARMONIC project to improve risk assessment by minimizing the uncertainty associated with cumulative dose calculations.

Cumulative Radiation Dose from Medical Imaging in Children with Congenital Heart Disease: A Systematic Review

Children with congenital heart disease are exposed to repeated medical imaging throughout their lifetime. Although the imaging contributes to their care and treatment, exposure to ionising radiation is known to increase one's lifetime attributable risk of malignancy. A systematic search of multiple databases was performed. Inclusion and exclusion criteria were applied to all relevant papers and seven were deemed acceptable for quality assessment and risk of bias assessment. The cumulative effective dose (CED) varied widely across the patient cohorts, ranging from 0.96 mSv to 53.5 mSv. However, it was evident across many of the included studies that a significant number of patients were exposed to a CED >20 mSv, the current annual occupational exposure limit. Many factors affected the dose which patients received, including age and clinical demographics. The imaging modality which contributed the most radiation dose to patients was cardiology interventional procedures. Paediatric patients with congenital heart disease are at an increased risk of receiving an elevated cumulative radiation dose across their lifetime. Further research should focus on identifying risk factors for receiving higher radiation doses, keeping track of doses, and dose optimisation where possible.

The cumulative radiation dose paradigm in pediatric imaging

Medical imaging professionals have an accountability for both quality and safety in the care of patients that have unexpected or anticipated repeated imaging examinations that use ionizing radiation. One measure in the safety realm for repeated imaging is cumulative effective dose (CED). CED has been increasingly scrutinized in patient populations, including adults and children. Recognizing the challenges with effective dose, including the cumulative nature, effective dose is still the most prevalent exposure currency for recurrent imaging examinations. While the responsibility for dose monitoring incorporates an element of tracking an individual patient cumulative radiation record, a more complex aspect is what should be done with this information. This challenge also differs between the pediatric and adult population, including the fact that high cumulative doses (e.g.,>100 mSv) are reported to occur much less frequently in children than in the adult population. It is worthwhile, then, to review the general construct of CED, including the comparison between the relative percentage occurrence in adult and pediatric populations, the relevant pediatric medical settings in which high CED occurs, the advances in medical care that may affect CED determinations in the future, and offer proposals for the application of the CED paradigm, considering the unique aspects of pediatric care.

Cumulative radiation doses due to nuclear medicine examinations: a systematic review

OBJECTIVES

To systematically review the published data regarding the cumulative exposure to radiation in selected cohorts of adults or paediatric patients due to diagnostic nuclear medicine examinations.

METHODS

We conducted PubMed/Medline searches of peer-reviewed papers on cumulated effective dose (CED) from diagnostic nuclear medicine procedures published between 01 January 2010 until 31 January 2021. Studies were considered eligible if the contribution of nuclear medicine examinations to total CED was >10%. Studies reporting cumulative doses in a single episode of care or in a limited time (≤1 year) were excluded. The main outcomes for which data were sought were the CED accrued by patients, the period in which the CED was accrued, the percentage of patients with CED > 100 mSv and the percentage contribution due to nuclear medicine procedures to the overall CED.

RESULTS

The studies included in the synthesis were 18 which enrolled a total of 1,76,371 patients. Eleven (1,757 patients), three (1,74,079 patients) and four (535 patients) were related to oncological, cardiologic and transplanted patients, respectively. All the studies were retrospective; some of the source materials referred to small number of patients and some of the patients were followed for a short time. Not many studies accurately quantified the contribution of nuclear medicine procedures to the overall radiation exposure due to medical imaging. Finally, most of the studies covered an observation period which extended mainly in the 2000-2010 decade.

CONCLUSIONS

There is a need of prospective, multicentric studies enrolling a greater number of patients, followed for longer period in selected groups of patients to fully capture the cumulative exposure to radiation in these settings.

ADVANCES IN KNOWLEDGE

This systematic review allows to identify selected group of patients with a specific health status in which the cumulated exposure to radiation may be of concern and where the contribution of nuclear medicine procedures to the total CED is significant.

Factors affecting high cumulative radiation exposure from paediatric computed tomography

Purpose

To estimate occurrence rate of high cumulative radiation exposure from paediatric computed tomography (CT), and to determine influential factors on high-dose inclination.

Material and methods

Patients below 18 years old receiving at least 50 mSv of a cumulative dose during a 5-year period in a tertiary care centre were retrospectively enrolled. Individual patient characteristics, diagnoses, frequency of exa-minations, scanner sites, designated scans, and effective doses were recorded. Collective doses were compared among groups of the diagnoses and scanner sites, and regression analyses were applied.

Results

Of 2771 patients, 3.2% received individual cumulative doses between 50 and 303 mSv (median, 74 mSv). Frequency of examinations ranged from 1 to 13 times (median, 4 times) per patient. About 70% of the patients had oncological illness. Radiation was predominantly high in a CT simulator that could contribute the percentage of collective dose to twice that of examinations owing to higher scanning parts and CT dose index. Some scanner sites used higher acquisition phases. Regression analysis showed that the number of scanning parts and phases significantly influenced the cumulative dose inclination (p < 0.05) while frequent examinations did not.

Conclusions

There was a low occurrence of paediatrics with high dose accumulation. Significant factors affecting potentially high exposure were customized CT protocols in the specific scanners.

Radiation protection perspective to recurrent medical imaging: what is known and what more is needed?

This review summarises the current knowledge about recurrent radiological imaging and associated cumulative doses to patients. The recent conservative estimates are for around 0.9 million patients globally who cumulate radiation doses above 100 mSv, where evidence exists for cancer risk elevation. Around one in five is estimated to be under the age of 50. Recurrent imaging is used for managing various health conditions and chronic diseases such as malignancies, trauma, end-stage kidney disease, cardiovascular diseases, Crohn's disease, urolithiasis, cystic pulmonary disease. More studies are needed from different parts of the world to understand the magnitude and appropriateness. The analysis identified areas of future work to improve radiation protection of individuals who are submitted to frequent imaging. These include access to dose saving imaging technologies; improved imaging strategies and appropriateness process; specific optimisation tailored to the clinical condition and patient habitus; wider utilisation of the automatic exposure monitoring systems with an integrated option for individual exposure tracking in standardised patient-specific risk metrics; improved training and communication. The integration of the clinical and exposure history data will support improved knowledge about radiation risks from low doses and individual radiosensitivity. The radiation protection framework will need to respond to the challenge of recurrent imaging and high individual doses. The radiation protection perspective complements the clinical perspective, and the risk to benefit analysis must account holistically for all incidental and long-term benefits and risks for patients, their clinical history and specific needs. This is a step toward the patient-centric health care.

Ionizing radiation exposure from dialysis tunneled catheters procedures: European directive and legal implications

BACKGROUND

Advances in medical imaging and interventional procedures have been associated with increased exposure to ionizing radiation. Thus, the International Commission on Radiological Protection (ICRP) established uniform safety standards to protect the general public against the dangers arising from ionizing radiations. In Europe, the ICRP standards are listed in the European Directive 2013/59/EURATOM, which should be transposed into national legislation by member states. They require that the administered dose must be part of the radiological report and identify the practitioners' responsibilities in justifying and optimizing the dose and correctly informing the patient.Despite these indications, the literature lacks information about the dose from fluoroscopically inserted dialysis tunneled central venous catheters (td-CVC). This study aimed to quantify the effective dose and organ dose to relevant organs in td-CVC to comply with the EU statements.

METHODS

We revised fluoroscopically-guided procedures of td-CVC insertion, considering dose per area product, fluoroscopic time, effective dose, organ dose, and anatomical district. We also compared these parameters with those of fluoroscopically inserted oncological central venous devices (Port-a-cath).

RESULTS

The dose-area product, fluoroscopic time, and organ dose for td-CVC were 13 ± 22.2 Gy*cm², 81 ± 129 s, and 1.9 ± 3.3 mSv. The radiological parameters for the left internal jugular, subclavian and femoral veins were similar but higher than for the right internal jugular vein. The radiological parameters were significantly higher for td-CVC than for Port-a-cath.

CONCLUSIONS

Fluoroscopically inserted td-CVC are associated with a relatively low dose of ionizing radiation, with considerable variability due to the anatomical puncture site and previous accesses' history. In light of the European Directive, it is a concern for nephrologists to be aware of the administered ionizing dose to comply with their legal responsibilities.

Cumulative effective dose from recurrent CT examinations in Europe: proposal for clinical guidance based on an ESR EuroSafe Imaging survey

In recent years, the issue of cumulative effective dose received from recurrent computed tomography examinations has become a subject of increasing concern internationally. Evidence, predominantly from the USA, has shown that a significant number of patients receive a cumulative effective dose of 100 mSv or greater. To obtain a European perspective, EuroSafe Imaging carried out a survey to collect European data on cumulative radiation exposure of patients from recurrent computed tomography examinations. The survey found that a relatively low percentage of patients (0.5%) received a cumulative effective dose equal to or higher than 100 mSv from computed tomography, most of them having an oncological disease. However, there is considerable variation between institutions as these values ranged from 0 to 2.72%, highlighting that local practice or, depending on the institution and its medical focus, local patient conditions are likely to be a significant factor in the levels of cumulative effective dose received, rather than this simply being a global phenomenon. This paper also provides some practical actions to support the management of cumulative effective dose and to refine or improve practice where recurrent examinations are required. These actions are focused around increasing awareness of referring physicians through encouraging local dialogue, actions focused on optimisation where a team approach is critical, better use of modern equipment and the use of Dose Management and Clinical Decision Support Systems together with focused clinical audits. The proper use of cumulative effective dose should be part of training programmes for referrers and practitioners, including what information to give to patients. Radiation is used to the benefit of patients in diagnostic procedures such as CT examinations, and in therapeutic procedures like the external radiation treatment for cancer. However, radiation is also known to increase the risk of cancer. To oversee this risk, the cumulative effective dose (CED) received by a patient from imaging procedures over his or her life is important. In this paper, the authors, on behalf of EuroSafe Imaging, report on a survey carried out in Europe that aims to estimate the proportion of patients that undergo CT examinations and are exposed to a CED of more than 100 mSv. At the same time, the survey enquires about and underlines radiologists' measures and radiology departments' strategies to limit such exposure. Over the period of 2015-2018, respondents reported that 0.5% (0-2.72%) of patients were exposed to a CED of ≥ 100 mSv from imaging procedures. The background radiation dose in Europe depends on the location, but it is around 2.5 mSv per year. It is obvious that patients with cancer, chronic diseases and trauma run the highest risk of having a high CED. However, even if the number of patients exposed to ≥ 100 mSv is relatively low, it is important to lower this number even further. Measures could consist in using procedures that do not necessitate radiation, using very low dose procedures, being very critical in requiring imaging procedures and increasing awareness about the issue. KEY POINTS: • A relatively low percentage of patients (0.5%) received a cumulative effective dose from CT computed tomography equal to or greater than 100 mSv, in Europe, most of them having an oncological disease. • There is a wide range in the number of patients who receive cumulative effective dose equal to or greater than 100 mSv (0-2.72%) and optimisation should be improved. • Increasing the awareness of referring physicians through encouraging local dialogue, concrete actions focused on optimisation and development of dose management systems is suggested.

Multinational data on cumulative radiation exposure of patients from recurrent radiological procedures: call for action

OBJECTIVES

To have a global picture of the recurrent use of CT imaging to a level where cumulative effective dose (CED) to individual patients may be exceeding 100 mSv at which organ doses typically are in a range at which radiation effects are of concern METHODS: The IAEA convened a meeting in 2019 with participants from 26 countries, representatives of various organizations, and experts in radiology, medical physics, radiation biology, and epidemiology. Participants were asked to collect data prior to the meeting on cumulative radiation doses to assess the magnitude of patients above a defined level of CED.

RESULTS

It was observed that the number of patients with CED ≥ 100 mSv is much larger than previously known or anticipated. Studies were presented in the meeting with data from about 3.2 million patients who underwent imaging procedures over periods of between 1 and 5 years in different hospitals. It is probable that an additional 0.9 million patients reach the CED ≥ 100 mSv every year globally.

CONCLUSIONS

There is a need for urgent actions by all stakeholders to address the issue of high cumulative radiation doses to patients. The actions include development of appropriateness criteria/referral guidelines by professional societies for patients who require recurrent imaging studies, development of CT machines with lower radiation dose than today by manufacturers, and development of policies by risk management organizations to enhance patient radiation safety. Alert values for cumulative radiation exposures of patients should be set up and introduced in dose monitoring systems.

KEY POINTS

• Recurrent radiological imaging procedures leading to high radiation dose to patients are more common than ever before. • Tracking of radiation exposure of individual patients provides useful information on cumulative radiation dose. • There is a need for urgent actions by all stakeholders to address the issue of high cumulative radiation doses to patients.

Radiation exposure in infants with oesophageal atresia and tracheo-oesophageal fistula

PURPOSE

Oesophageal atresia and tracheo-oesophageal atresia require surgical repair in early infancy. These children have significant disease-related morbidity requiring frequent radiological examinations resulting in an increased malignancy risk.

METHODS

A single-centre, retrospective review was performed of radiation exposure in children with OA/TOF born 2011-2015. Medical records were reviewed to determine the number and type of imaging studies involving ionising radiation exposure enabling the calculation of the estimated effective dose per child over the first year of life.

RESULTS

Forty-nine children were included. Each child underwent a median of 19 (IQR 11.5-35) imaging studies, which were primarily plain radiography (median = 14, IQR 7-26.5). The overall median estimated effective dose per patient was 4.7 (IQR 3.0-9.4) mSv, with the majority of radiation exposure resulting from fluoroscopic imaging (median 3.3 mSv, IQR 2.2-6.0). 'Routine' postoperative oesophagrams showed no leak in 35/36 (97%) with the remaining study showing an insignificant leak that did not alter management.

CONCLUSIONS

Careful consideration should be given to the use of imaging in OA/TOF to minimise morbidity in these vulnerable infants. Oesophagrams in children without the symptoms of anastomotic leak or stricture should be discontinued. Standardisation of monitoring protocols with regard to radiation exposure should be considered.

Decreasing Radiograph Errors in Pediatric Sports Medicine Clinic

Background:

Radiographs are frequently ordered for general musculoskeletal complaints in the outpatient setting. However, incorrect laterality, incorrect location, or unnecessary radiographs have been reported as errors in our clinics. This quality improvement (QI) project aimed to reduce incorrect duplicate radiographs in outpatient pediatric sports medicine clinic. The overall global goal was to stop unnecessary radiation exposure in our pediatric patients.

Methods:

Using QI methodology, we evaluated the current clinic flow, the process of ordering radiographs, and the completion of radiographs at the main sports medicine outpatient clinic. Staff communication, staff education, and patient participation were identified as the prominent gaps in our clinic process. We implemented interventions using progressive biweekly Plan-Do-Study-Act (PDSA) cycles to promote change and to reduce our radiographic errors.

Results:

Retrospective baseline data demonstrated baseline errors of 9% (10/106) in the main outpatient clinic. After 6 months of PDSA cycles, we found no duplicate errors. Highly successful interventions included radiograph screening survey for families, staff education, and improved staff communication. The project was expanded to a second outpatient clinic with baseline errors of 6% (4/64). After 2 months of PDSA cycles, no duplicate errors were found.

Conclusion:

Our goal was to reduce incorrect duplicate radiographs in outpatient sports medicine clinic and limit unnecessary radiation exposure in our pediatric patients. A reduction in duplicate errors at 2 clinics occurred using the Institute for Healthcare Improvement model to facilitate change. Effective communication between physicians, clinical athletic trainers, radiology technologists, patients, and families drove the success of this quality improvement initiative.

Progress in the treatment and outcome of pediatric inflammatory bowel disease patients

INTRODUCTION

The number of pediatric patients with inflammatory bowel disease (IBD), namely Crohn´s disease, ulcerative colitis and unclassified colitis, has rapidly increased in Western countries. Areas covered: This review discusses how the treatment of pediatric IBD patients has improved,with attention given to therapeutic quality and cost. The literature search covers Medline-PubMed and the Cochrane Library, with February 2016 as the last search dates. Similarly to what has been the trend in the management of adult IBD, pediatric IBD therapy has become more active than before. High use of immunosuppressants and the availability of biological therapeutic agents has helped to control the extensive and aggressive course of pediatric IBD. Full disease control at an early phase has advantages such as preserving normal child growth and development, maintaining overall good health and quality of life, as well as decreasing the psychosocial burden of the disease. Expert commentary: A key research direction is to tailor treatment modalities according to anticipated individual phenotype and disease course. Another is to reduce healthcare costs by decreasing the so-far high rate of surgery of pediatric IBD patients, and, instead, to develop a more active approach to treatment than before.

The lateral plane delivers higher dose than the frontal plane in biplane cardiac catheterization systems

The objective of the study is to compare radiation dose between the frontal and lateral planes in a biplane cardiac catheterization laboratory. Tube angulation progressively increases patient and operator radiation dose in single-plane cardiac catheterization laboratories. This retrospective study captured biplane radiation dose in a pediatric cardiac catheterization laboratory between April 2010 and January 2014. Raw and time-indexed fluoroscopic, cineangiographic and total (fluoroscopic + cineangiographic) air kerma (AK, mGy) and kerma area product (PKA, µGym(2)/Kg) for each plane were compared. Data for 716 patients were analyzed: 408 (56.98 %) were male, the median age was 4.86 years, and the median weight was 17.35 kg. Although median beam-on time (minutes) was 4.2 times greater in the frontal plane, there was no difference in raw median total PKA between the two planes. However, when indexed to beam-on time, the lateral plane had a higher median-indexed fluoroscopic (0.75 vs. 1.70), cineangiographic (16.03 vs. 24.92), and total (1.43 vs. 5.15) PKA (p < 0.0001). The median time-indexed total PKA in the lateral plane is 3.6 times the frontal plane. This is the first report showing that the lateral plane delivers a higher dose than the frontal plane per unit time. Operators should consciously reduce the lateral plane beam-on time and incorporate this practice in radiation reduction protocols.