Reduction of radiation to children: our responsibility to change

Long-term trends in total administered radiation dose from brain [18F]FDG-PET in children with drug-resistant epilepsy

PURPOSE

To assess the trends in administered 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) doses, computed tomography (CT) radiation doses, and image quality over the last 15 years in children with drug-resistant epilepsy (DRE) undergoing hybrid positron emission tomography (PET) brain scans.

METHODS

We retrospectively analyzed data from children with DRE who had [18F]FDG-PET/CT or magnetic resonance scans for presurgical evaluation between 2005 and 2021. We evaluated changes in injected [18F]FDG doses, administered activity per body weight, CT dose index volume (CTDIvol), and dose length product (DLP). PET image quality was assessed visually by four trained raters. Conversely, CT image quality was measured using region-of-interest analysis, normalized by signal-to-noise (SNR) and contrast-to-noise ratio (CNR).

RESULTS

We included 55 children (30 male, mean age: 9 ± 6 years) who underwent 61 [18F]FDG-PET scans (71% as PET/CT). Annually, the injected [18F]FDG dose decreased by ~ 1% (95% CI: 0.92%-0.98%, p < 0.001), with no significant changes in administered activity per body weight (p = 0.51). CTDIvol and DLP decreased annually by 16% (95% CI: 9%-23%) and 15% (95% CI: 8%-21%, both p < 0.001), respectively. PET image quality improved by 9% year-over-year (95% CI: 6%-13%, p < 0.001), while CT-associated SNR and CNR decreased annually by 7% (95% CI: 3%-11%, p = 0.001) and 6% (95% CI: 2%-10%, p = 0.008), respectively.

CONCLUSION

Our findings indicate stability in [18F]FDG administered activity per body weight alongside improvements in PET image quality. Conversely, CT-associated radiation doses reduced. These results reaffirm [18F]FDG-PET as an increasingly safer and higher-resolution auxiliary imaging modality for children with DRE. These improvements, driven by technological advancements, may enhance the diagnostic precision and patient outcomes in pediatric epilepsy surgery.

The burden of radiation exposure in congenital heart disease: the Italian cohort profile and bioresource collection in HARMONIC project

BACKGROUND

The European-funded Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) project aims to improve knowledge on the effects of medical exposure to ionizing radiation (IR) received during childhood. One of its objectives is to build a consolidated European cohort of pediatric patients who have undergone cardiac catheterization (Cath) procedures, with the goal of enhancing the assessment of long-term radiation-associated cancer risk. The purpose of our study is to provide a detailed description of the Italian cohort contributing to the HARMONIC project, including an analysis of cumulative IR exposure, reduction trend over the years and an overview of the prospective collection of biological samples for research in this vulnerable population.

METHODS

In a single-center retrospective cohort study, a total of 584 patients (323 males) with a median age of 6 (2-13) years, referred at the Pediatric Cardiology in Niguarda Hospital from January 2015 to October 2023, were included. Biological specimens from a subset of 60 patients were prospectively collected for biobanking at baseline, immediately post-procedure and after 12 months.

RESULTS

Two hundred fifty-nine (44%) patients were under 1 year old at their first procedure. The median KAP/weight was 0.09 Gy·cm2/kg (IQR: 0.03-0.20), and the median fluoroscopy time was 8.10 min (IQR: 4.00-16.25). KAP/weight ratio showed a positive correlation with the fluoroscopy time (Spearman's rho = 0.679, p < 0.001). Significant dose reduction was observed either after implementation of an upgraded technology system and a radiation training among staff. The Italian cohort includes 1858 different types of specimens for Harmonic biobank, including blood, plasma, serum, clot, cell pellet/lymphocytes, saliva.

CONCLUSIONS

In the Italian Harmonic cohort, radiation dose in cardiac catheterization varies by age and procedure type. An institution's radiological protection strategy has contributed to a reduction in radiation dose over time. Biological samples provide a valuable resource for future research, offering an opportunity to identify potential early biomarkers for health surveillance and personalized risk assessment.

Artificial intelligence in coronary artery calcium score: rationale, different approaches, and outcomes

Almost 35 years after its introduction, coronary artery calcium score (CACS) not only survived technological advances but became one of the cornerstones of contemporary cardiovascular imaging. Its simplicity and quantitative nature established it as one of the most robust approaches for atherosclerotic cardiovascular disease risk stratification in primary prevention and a powerful tool to guide therapeutic choices. Groundbreaking advances in computational models and computer power translated into a surge of artificial intelligence (AI)-based approaches directly or indirectly linked to CACS analysis. This review aims to provide essential knowledge on the AI-based techniques currently applied to CACS, setting the stage for a holistic analysis of the use of these techniques in coronary artery calcium imaging. While the focus of the review will be detailing the evidence, strengths, and limitations of end-to-end CACS algorithms in electrocardiography-gated and non-gated scans, the current role of deep-learning image reconstructions, segmentation techniques, and combined applications such as simultaneous coronary artery calcium and pulmonary nodule segmentation, will also be discussed.

The Fluoroless Future in Electrophysiology: A State-of-the-Art Review

Fluoroscopy has always been the cornerstone imaging method of interventional cardiology procedures. However, radiation exposure is linked to an increased risk of malignancies and multiorgan diseases. The medical team is even more exposed to X-rays, and a higher incidence of malignancies was reported in this professional group. In the last years, X-ray exposure has increased rapidly, involving, above all, the medical team and young patients and forcing alternative fluoroless imaging methods. In cardiac electrophysiology (EP) and pacing, the advent of 3D electroanatomic mapping systems with dedicated catheters has allowed real-time, high-density reconstruction of both heart anatomy and electrical activity, significantly reducing the use of fluoroscopy. In addition, the diffusion of intracardiac echocardiography has provided high anatomical resolution of moving cardiac structures, providing intraprocedural guidance for more complex catheter ablation procedures. These methods have largely demonstrated safety and effectiveness, allowing for a dramatic reduction in X-ray delivery in most arrhythmias' ablations. However, some technical concerns, as well as higher costs, currently do not allow their spread out in EP labs and limit their use to only procedures that are considered highly complex and time-consuming and in young patients. In this review, we aim to update the current employment of fluoroless imaging in different EP procedures, focusing on its strengths and weaknesses.

Lympho-hematopoietic malignancies risk after exposure to low dose ionizing radiation during cardiac catheterization in childhood

Pediatric patients with congenital heart disease (CHD) often undergo low dose ionizing radiation (LDIR) from cardiac catheterization (CC) for the diagnosis and/or treatment of their disease. Although radiation doses from a single CC are usually low, less is known about the long-term radiation associated cancer risks. We aimed to assess the risk of lympho-hematopoietic malignancies in pediatric CHD patients diagnosed or treated with CC. A French cohort of 17,104 children free of cancer who had undergone a first CC from 01/01/2000 to 31/12/2013, before the age of 16 was set up. The follow-up started at the date of the first recorded CC until the exit date, i.e., the date of death, the date of first cancer diagnosis, the date of the 18th birthday, or the 31/12/2015, whichever occurred first. Poisson regression was used to estimate the LDIR associated cancer risk. The median follow-up was 5.9 years, with 110,335 person-years. There were 22,227 CC procedures, yielding an individual active bone marrow (ABM) mean cumulative dose of 3.0 milligray (mGy). Thirty-eight incident lympho-hematopoietic malignancies were observed. When adjusting for attained age, gender and predisposing factors to cancer status, no increased risk was observed for lympho-hematopoietic malignancies RR/mGy = 1.00 (95% CI: 0.88; 1.10). In summary, the risk of lympho-hematopoietic malignancies and lymphoma was not associated to LDIR in pediatric patients with CHD who undergo CC. Further epidemiological studies with greater statistical power are needed to improve the assessment of the dose-risk relationship.

A Longitudinal Study of Individual Radiation Responses in Pediatric Patients Treated with Proton and Photon Radiotherapy, and Interventional Cardiology: Rationale and Research Protocol of the HARMONIC Project

The Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy (photon and proton) in Pediatrics (HARMONIC) is a five-year project funded by the European Commission that aimed to improve the understanding of the long-term ionizing radiation (IR) risks for pediatric patients. In this paper, we provide a detailed overview of the rationale, design, and methods for the biological aspect of the project with objectives to provide a mechanistic understanding of the molecular pathways involved in the IR response and to identify potential predictive biomarkers of individual response involved in long-term health risks. Biological samples will be collected at three time points: before the first exposure, at the end of the exposure, and one year after the exposure. The average whole-body dose, the dose to the target organ, and the dose to some important out-of-field organs will be estimated. State-of-the-art analytical methods will be used to assess the levels of a set of known biomarkers and also explore high-resolution approaches of proteomics and miRNA transcriptomes to provide an integrated assessment. By using bioinformatics and systems biology, biological pathways and novel pathways involved in the response to IR exposure will be deciphered.

Congenital Heart Disease and the Risk of Cancer: An Update on the Genetic Etiology, Radiation Exposure Damage, and Future Research Strategies

Epidemiological studies have shown an increased prevalence of cancer in patients with congenital heart disease (CHD) as compared with the general population. The underlying risk factors for the acquired cancer risk remain poorly understood, and shared genetic anomalies and cumulative radiation exposure from repeated imaging and catheterization procedures may be contributing factors. In the present review, we provide an update on the most recent literature regarding the associations between CHD and cancer, with a particular focus on genetic etiology and radiation exposure from medical procedures. The current evidence indicates that children with CHD may be a high-risk population, already having the first genetic “hit”, and, consequently, may have increased sensitivity to ionizing radiation from birth or earlier. Future research strategies integrating biological and molecular measures are also discussed in this article.

Nuclear Imaging in Pediatric Cardiology: Principles and Applications

Nuclear imaging plays a unique role within diagnostic imaging since it focuses on cellular and molecular processes. Using different radiotracers and detection techniques such as the single photon emission scintigraphy or the positron emission tomography, specific parameters can be assessed: myocardial perfusion and viability, pulmonary perfusion, ventricular function, flow and shunt quantification, and detection of inflammatory processes. In pediatric and congenital cardiology, nuclear imaging can add complementary information compared to other imaging modalities such as echocardiography or magnetic resonance imaging. In this state-of-the-art paper, we appraise the different techniques in pediatric nuclear imaging, evaluate their advantages and disadvantages, and discuss the current clinical applications.

Exposure to low-dose ionising radiation from cardiac catheterisation and risk of cancer: the COCCINELLE study cohort profile

PURPOSE

The COCCINELLE study is a nationwide retrospective French cohort set up to evaluate the risk of cancer in patients who undergone cardiac catheterisation (CC) procedures for diagnosis or treatment of congenital heart disease during childhood.

PARTICIPANTS

Children who undergone CC procedures from 1 January 2000 to 31 December 2013, before the age of 16 in one of the 15 paediatric cardiology departments which perform paediatric CC in mainland France were included. The follow-up started at the date of the first recorded CC procedure until the exit date, that is, the date of death, the date of first cancer diagnosis, the date of the 18th birthday or the 31 December 2015, whichever occurred first. The cohort was linked to the National Childhood Cancer Registry to identify patients diagnosed with cancer and with the French National Directory for the Identification of Natural Persons to retrieve the patients' vital status.

FINDINGS TO DATE

A total of 17 104 children were included in the cohort and followed for 110 335 person-years, with 22 227 CC procedures collected. Among the patients, 81.6% received only one procedure. Fifty-nine cancer cases were observed in the cohort. Standardised incidence ratios (SIRs) were increased for all-cancer (SIR=3.8, 95% CI: 2.9 to 4.9), leukaemia (SIR=3.3, 95% CI: 2.0 to 5.4), lymphoma (SIR=14.9, 95% CI: 9.9 to 22.5) and solid cancers excluding central nervous system (CNS) tumours (SIR=3.3, 95% CI: 2.0 to 5.5) compared with the general population.

FUTURE PLANS

Dose reconstruction is currently underway to estimate individual cumulative doses absorbed to relevant organs, including red bone marrow and brain for respectively haematologic disorders and CNS tumours risk estimation. A dose-response analysis will be conducted with consideration to confounding factors such as age at exposure, gender, predisposing factors to cancer and other sources of medical diagnostic low-dose ionising radiation.

Estimation of radiation exposure of children undergoing superselective intra-arterial chemotherapy for retinoblastoma treatment: assessment of local diagnostic reference levels as a function of age, sex, and interventional success

PURPOSE

This study aims to determine local diagnostic reference levels (LDRLs) of intra-arterial chemotherapy (IAC) procedures of pediatric patients with retinoblastoma (RB) to provide data for establishing diagnostic reference levels (DRLs) in pediatric interventional radiology (IR).

METHODS

In a retrospective study design, LDRLs and achievable dose (AD) were assessed for children undergoing superselective IAC for RB treatment. All procedures were performed at the flat-panel angiography systems (I) ArtisQ biplane (Siemens Healthineers) and (II) Allura Xper (Philips Healthcare). Patients were differentiated according to age (A1: 1-3 months; A2: 4-12 months; A3: 13-72 months; A4: 73 months-10 years; A5: > 10 years), sex, conducted or not-conducted chemotherapy.

RESULTS

248 neurointerventional procedures of 130 pediatric patients (median age 14.5 months, range 5-127 months) with RB (68 unilateral, 62 bilateral) could be included between January 2010 and March 2020. The following diagnostic reference values, AD, and mean values could be determined: (A2) DRL 3.9 Gy cm², AD 2.9 Gy cm², mean 3.5 Gy cm²; (A3) DRL 7.0 Gy cm², AD 4.3 Gy cm², mean 6.0 Gy cm²; (A4) DRL 14.5 Gy cm², AD 10.7 Gy cm², mean 10.8 Gy cm²; (A5) AD 8.8 Gy cm², mean 8.8 Gy cm². Kruskal-Wallis-test confirmed a significant dose difference between the examined age groups (A2-A5) (p < 0.001). There was no statistical difference considering sex (p = 0.076) and conducted or not-conducted chemotherapy (p = 0.627). A successful procedure was achieved in 207/248 cases.

CONCLUSION

We report on radiation exposure during superselective IAC of a pediatric cohort at the German Retinoblastoma Referral Centre. Although an IAC formally represents a therapeutic procedure, our results confirm that radiation exposure lies within the exposure of a diagnostic interventional procedure. DRLs for superselective IAC are substantially lower compared with DRLs of more complex endovascular interventions.

Intracardiac echocardiography versus fluoroscopy for endovascular and endocardial catheter navigation during cryo-ablation of the slow pathway in AVNRT patients

Background

A new zero-fluoroscopy technique for electrophysiology catheter navigation relying on intracardiac echocardiography (ICE) has been recently reported (Ice&ICE trial). We investigated potential differences in efficacy, safety or procedural performance between conventional fluoroscopy- and ICE-guided cryothermal ablation (CA) in symptomatic AVNRT patients.

Methods

Clinical and electrophysiological data of AVNRT patients included in the Ice&ICE trial (22 patients, 16 females; =zero-fluoroscopy group) were compared to those of consecutive AVNRT patients, who underwent fluoroscopy-guided CA (25 patients, 17 females; = fluoroscopy group) during the last 2 years in our institution.

Results

Slow pathway ablation or modulation was successful in all patients. Fluoroscopy time and radiation dose in the fluoroscopy group were 11.2 ± 9.0 min and 20.3 ± 16.2Gycm², whereas no fluoroscopy was used in the opposite group (p <  0.001, respectively). EPS duration was not different between the groups (zero-fluoroscopy:101.6 ± 40.2 min, fluoroscopy:99.4 ± 37.2 min, p = n.s.). Catheter placement time was significantly shorter in the fluoroscopy group (2.2 ± 1.6 min vs. 12.0 ± 7.5 min, p <  0.05), whereas cryo-application duration (from the first cryo-mapping to the last CA) was significantly shorter in the zero-fluoroscopy group (27.5 ± 37.0 min vs. 38.1 ± 33.9 min, p <  0.05). Mean cryo-mapping and CA applications were numerically lower in the zero-fluoroscopy group (CM:7.5 ± 5.7 vs. 8.8 ± 6.2; CA:3.1 ± 1.7 vs. 3.2 ± 2.0, p = n.s.). No major adverse events occurred in both groups. After 15.0 ± 4.2 months, arrhythmia recurrence was not different between the groups (4.5% vs. 8.0%, p = n.s.).

Conclusions

Zero-fluoroscopy ICE-guided EP catheter navigation shows comparable efficacy and safety to fluoroscopic guidance during CA in AVNRT patients. ICE visualization of catheters and endocardial structures within the triangle of Koch shortens the cryo-application duration, though time needed for catheter placement is longer, when compared with conventional fluoroscopic guidance, which results in similar mean EPS duration with both navigation techniques.

Trial registration

(German Clinical Trials Register ID: DRKS00011360; Registration Date 14.12.2016)

Electronic supplementary material

The online version of this article (10.1186/s12947-019-0162-2) contains supplementary material, which is available to authorized users.

Radiation exposure of image-guided intrathecal administration of nusinersen to adult patients with spinal muscular atrophy

PURPOSE

To examine diagnostic reference levels (DRL) and achievable doses (AD) of image-guided and size-specific dose estimates (SSDE) and organ and effective doses of CT-guided intrathecal nusinersen administration to adult patients with spinal muscular atrophy (SMA).

METHODS

This study involved a total of 60 image-guided intrathecal nusinersen treatments between August 2017 and June 2018. Patient cohort comprised 14 adult patients with the following SMA types: type 2 (n = 9) and type 3 (n = 5) with a mean age of 33.6 years (age range 25-57 years). DRL, AD, SSDE, organ, and effective doses were assessed with a dose-monitoring program based on the Monte Carlo simulation techniques.

RESULTS

DRL and AD for computed tomography are summarised as follows: in terms of CT-dose index (CTDI_vol), DRL 56.4 mGy and AD 36.7 mGy; in terms of dose-length product (DLP), DRL 233.1 mGy cm and AD 120.1 mGy cm. DRL and AD for fluoroscopic guidance were distributed as follows: in terms of dose-area product (DAP), DRL 239.1 μGy m² and AD 135.2 mGy cm². Mean SSDE was 9.2 mGy. Mean effective dose of the CT-guided injections was 2.5 mSv (median 2.0 mSv, IQR 1.3-3.2 mSv). Highest organ doses in the primary beam of radiation were the small intestine 12.9 mSv, large intestine 9.5 mSv, and ovaries 3.6 mSv.

CONCLUSION

Radiation exposure of SMA patients measured as DRLs is generally not higher compared with patients without SMA despite severe anatomical hazards. Dose monitoring data may allow clinicians to stratify radiation risk, identify organs at risk, and adopt measures for specific radiation dose reduction.

Three-Dimensional Rotational Angiography in the Pediatric Cath Lab: Optimizing Aortic Interventions

The aim of this study was to evaluate usability and accuracy of three-dimensional rotational angiography (3DRA) during interventions of the aorta in congenital heart disease (CHD). 3DRA is an accurate, encompassing and fast imaging technique in the cath lab. However, there is only few published data about its use during interventions in CHD. Between January 2010 and January 2014, 3DRA was performed in 77 patients with aortic issues: in 65 % cases, an intervention was performed, of which 72 % had aortic isthmus stenosis. Data were obtained retrospectively. The accuracy of 3DRA was evaluated on the basis of comparative measurements (n = 60) of the aortic diameter between 3DRA and conventional biplane angiography. Measurements presented a high accuracy with an average deviation of 3.89 % [±3 %] and a significant correlation of r = 0.99 after Pearson (p < 0.0001). Clinical benefit was assessed using a five-point Likert scale and could be shown in 98 %. Comparison with a control group showed a reduced fluoroscopy time from 10.2 to 8.30 min (median, p < 0.01) and decreased radiation dose of 0.18 compared to 0.56 Gy cm(2)/kg (median, p < 0.02). The use of 3DRA in patients with aortic anomalies has advantages in comparison with conventional angiography. It improves diagnostic accuracy, and 3D guidance enables a faster and simplified intervention with enhanced patients' safety and the potential to reduce radiation dose.

Computed tomography imaging in children with congenital heart disease: Indications and radiation dose optimization

Computed tomography (CT) technology is acquiring a key role in the diagnostic process of complex cardiac congenital anomalies. Recent advances and improvements in spatial and temporal resolution and radiation dose are encouraging the use of CT scanning in children. Paediatric cardiologists should have a good knowledge of the potential of CT techniques and their limitations to plan and properly perform CT examinations without forgetting radiation concerns. In this paper, we will discuss the principal indications for CT scans in newborns and children in our clinical practice. We will also outline the most-used strategies for dose reduction. Basic knowledge about the various CT techniques is crucial, not only to perform, but also to interpret CT results, thus helping the medical and surgical management of patients.

Radiation dose reduction in paediatric coronary computed tomography: assessment of effective dose and image quality

OBJECTIVES

To assess the impact of different protocols on radiation dose and image quality for paediatric coronary computed tomography (cCT).

MATERIALS AND METHODS

From January-2012 to June-2014, 140 children who underwent cCT on a 64-slice scanner were included. Two consecutive changes in imaging protocols were performed: 1) the use of adaptive statistical iterative reconstruction (ASIR); 2) the optimization of acquisition parameters. Effective dose (ED) was calculated by conversion of the dose-length product. Image quality was assessed as excellent, good or with significant artefacts.

RESULTS

Patients were divided in three age groups: 0-4, 5-7 and 8-18 years. The use of ASIR combined to the adjustment of scan settings allowed a reduction in the median ED of 58 %, 82 % and 85 % in 0-4, 5-7 and 8-18 years group, respectively (7.3 ± 1.4 vs 3.1 ± 0.7 mSv, 5.5 ± 1.6 vs 1 ± 1.9 mSv and 5.3 ± 5.0 vs 0.8 ± 2.0 mSv, all p < 0,05). Prospective protocol was used in 51 % of children. The reduction in radiation dose was not associated with reduction in diagnostic image quality as assessed by the frequency of coronary segments with excellent or good image quality (88 %).

CONCLUSIONS

cCT can be obtained at very low radiation doses in children using ASIR, and prospective acquisition with optimized imaging parameters.

KEY POINTS

• Using ASIR allows 25 % to 41 % reduction in the ED. • Prospective protocol is used up to 51 % of children after premedication. • Low dose is possible using ASIR and optimized prospective paediatric cCT.

The risk of cumulative radiation exposure in chest imaging and the advantage of bedside ultrasound

The increasing use and complexity of imaging techniques have not been matched by increasing awareness and knowledge by prescribers and practitioners. Imaging examinations that expose to ionizing radiation provide immense benefits when appropriate, yet they may result in an increased incidence of radiation-induced cancer in the long-term. The radiation issue is relevant not only for the individual patient but also for the community because small individual risks multiplied by millions of examinations become a significant population risk. As recently highlighted by recent European and American Guidelines, the long-term risk associated with radiation exposure should be considered in the risk-benefit assessment behind appropriate prescription of diagnostic testing.