Early life ionizing radiation exposure and cancer risks: systematic review and meta-analysis

Environmental pollution and cancer

OBJECTIVE

To identify and describe pollutants with carcinogenic potential that contaminate indoor and outdoor air, food and soil.

DATA SOURCE

The descriptors environmental pollutants, occupational cancer, prevention and soil pollutants were used to conduct the research for literature review. Articles published from 2003 to 2024 in the electronic databases Pubmed Medline, Lilacs and Scielo, in Portuguese and English, were included.

SUMMARY OF FINDINGS

There are multiple sources of pollution in the external and internal environments, including motor vehicles, industrial facilities, smoke from tobacco products, agricultural activities, fires and domestic combustion devices. The most important pollutants related to chemical substances include all forms of asbestos, benzene, exhaust gases from gasoline engines, food and water contaminants, such as arsenic and inorganic arsenic compounds, in addition to persistent organic pollutants, such as dioxins. The use of fossil fuels and biomass for domestic heating are also important sources of pollution. The carcinogenic potential of pollutants varies according to the sources of pollution, climate conditions and the region's topography.

CONCLUSIONS

Global environmental pollution is an international public health problem with multiple health effects. Many environmental pollutants are proven to be carcinogenic to adults, while few causes have been scientifically established for children. Pollution is mainly caused by uncontrolled urbanization and industrialization. Preventing environmental exposure to carcinogenic pollutants requires both government regulation and community action and commitment.

Performance of Lung-Nodule Computer-Aided Detection Systems on Standard-Dose and Low-Dose Pediatric CT Scans: An Intraindividual Comparison

Background: When applying lung-nodule computer-aided detection (CAD) systems for pediatric CT, performance may be degraded on low-dose scans due to increased image noise. Objective: To conduct an intraindividual comparison of the performance for lung nodule detection of two CAD systems trained using adult data between low-dose and standard-dose pediatric chest CT scans. Methods: This retrospective study included 73 patients (32 female, 41 male; mean age, 14.7 years; age range, 4-20 years) who underwent both clinical standard-dose and investigational low-dose chest CT examinations within the same encounter from November 30, 2018 to August 31, 2020 as part of an earlier prospective study. Fellowship-trained pediatric radiologists annotated lung nodules to serve as the reference standard. Both CT scans were processed using two publicly available lung-nodule CAD systems previously trained using adult data: FlyerScan and Medical Open Network for Artificial Intelligence (MONAI). The systems' sensitivities for nodules measuring 3-30 mm (n=247) were calculated when operating at a fixed frequency of two false-positives per scan. Results: FlyerScan exhibited detection sensitivities of 76.9% (190/247; 95% CI: 73.3-80.8%) on standard-dose scans and 66.8% (165/247; 95% CI: 62.6-71.5) on low-dose scans. MONAI exhibited detection sensitivities of 67.6% (167/247, 95% CI: 61.5-72.1) on standard-dose scans and 62.3% (154/247, 95% CI: 56.1-66.5%) on low-dose scans. The number of detected nodules for standard-dose versus low-dose scans for 3-mm nodules was 33 versus 24 (FlyerScan) and 16 versus 13 (MONAI), 4-mm nodules was 46 versus 42 (FlyerScan) and 39 versus 30 (MONAI), 5-mm nodules was 38 versus 33 (FlyerScan) and 32 versus 31 (MONAI), and 6-mm nodules was 27 versus 20 (FlyerScan) and 24 versus 24 (MONAI). For nodules measuring ≥7 mm, detection did not show a consistent pattern between standard-dose and low-dose scans for either system. Conclusions: Two lung-nodule CAD systems demonstrated decreased sensitivity on low-dose versus standard-dose pediatric CT scans performed in the same patients. The reduced detection at low dose was overall more pronounced for nodules measuring less than 5 mm. Clinical Impact: Caution is needed when using low-dose CT protocols in combination with CAD systems to help detect small lung nodules in pediatric patients.

Evaluation of children applying to emergency service after motor vehicle trauma

BACKGROUND

Traffic accidents are significant causes of death and serious injury in children. Children's clinical findings are more subtle and there is a risk of faster deterioration. On the other hand, radiation sensitivity due to imaging is also high. These challenging factors highlight the importance of approaching pediatric trauma cases. In our study, we aimed to contribute to current approaches by examining the clinical course and profiles of children involved in traffic accidents. This study aimed to analyze the profiles and clinical courses of children involved in road traffic accidents.

METHODS

Pediatric patients brought to our hospital due injuries from traffic accidents were retrospectively investigated.

RESULTS

During the two-year period analyzed in the study, 605 child patients applied due to traffic accidents, accounting for 5.4 % of pediatric trauma cases. The majority of the children were between the ages of 12-17, with most accidents occurring in the summer. In total, 56.9 % were from in-vehicle traffic accidents, 36.7 % were from extra-vehicular traffic accidents, and 6.4 % were from motorcycle accidents. The imaging rate among the patients was 89 %, and 50.6 % had more than one tomography. More than half of the cases had no pathological findings, and only 6 % required hospitalization. Most cases were treated successfully with medical care, while 21.4 % needed interventional procedures, and 10 % received no treatment. The most common injuries were superficial skin lesions (11.1 %) and extremity fractures (10.2 %), with orthopedics being the most consulted department. Fractures were most common in the tibia and were more likely in motorcycle accidents than in-car accidents.

CONCLUSION

In-vehicle accidents were the most frequent type of accident, and children under 4 years old had a higher incidence of in-car accidents than other age groups. Males made up 60 % of the cases, with boys having higher rates of motorcycle and extra-vehicular accidents compared to girls. While most children had no injuries from the accidents, those who did generally recovered well with outpatient monitoring. On the other hand, 89 % of patients underwent imaging at a high rate.

Biomarkers of mitochondrial stress and DNA damage during pediatric catheter-directed neuroangiography - a prospective single-center study

BACKGROUND

Neuroangiography represents a critical diagnostic and therapeutic imaging modality whose associated radiation may be of concern in children. The availability of in vivo radiation damage markers would represent a key advancement for understanding radiation effects and aid in the development of radioprotective strategies.

OBJECTIVE

Determine if biomarkers of cellular damage can be detected in the peripheral blood mononuclear cells (PBMC) of children undergoing neuroangiography.

MATERIALS AND METHODS

Prospective single-site study of 27 children. Blood collected pre and post neuroangiography, from which PBMC were isolated and assayed for biomarkers of mitochondrial stress (mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and mitochondrial DNA (mtDNA)) and DNA damage (γH2AX). Dose response of biomarkers vs. radiation dose was analyzed using linear regressions. The cohort was divided into higher (HD) and lower dose (LD) groups and analyzed using linear mixed models and compared using Welch's t-tests.

RESULTS

No biomarker exhibited a dose-dependent response following radiation (γH2AX: R2 = 0.0012, P = 0.86; MMP: R2 = 0.016, P = 0.53; mtDNA: R2 = 0.10, P = 0.11; ROS: R2 = 0.0023, P = 0.81). Groupwise comparisons showed no significant differences in γH2AX or ROS after radiation (γH2AX: LD: 0.6 ± 6.0, P = 0.92; HD: -7.5 ± 6.3 AU, P = 0.24; ROS: LD: 1.3 ± 2.8, P = 0.64; HD: -3.6 ± 3.0 AU, P = 0.24). Significant changes were observed to mitochondrial markers MMP (-53.7 ± 14.7 AU, P = 0.0014) and mtDNA (-1.1 ± 0.4 AU, P = 0.0092) for HD, but not the LD group (MMP: 26.1 ± 14.7 AU, P = 0.090; mtDNA: 0.2 ± 0.4, P = 0.65).

CONCLUSIONS

Biomarkers of mitochondrial stress in PBMC were identified during pediatric neuroangiography and warrant further investigation for radiation biodosimetry. However, isolating radiation-specific effects from those of procedural stress and general anesthesia requires further investigation.

NeuroMix with MRA: A Fast MR Protocol to Reduce Head and Neck CTA for Patients with Acute Neurologic Presentations

BACKGROUND AND PURPOSE

Overuse of CT-based cerebrovascular imaging in the emergency department and inpatient settings, notably CTA of the head and neck for minor and nonfocal neurologic presentations, stresses imaging services and exposes patients to radiation and contrast. Furthermore, such CT-based imaging is often insufficient for definitive diagnosis, necessitating additional MR imaging. Recent advances in fast MRI may allow timely assessment and a reduced need for head and neck CTA in select populations.

MATERIALS AND METHODS

We identified inpatients or patients in the emergency department who underwent CTAHN (including noncontrast and postcontrast head CT, with or without CTP imaging) followed within 24 hours by a 3T MRI study that included a 2.5-minute unenhanced multicontrast sequence (NeuroMix) and a 5-minute intracranial time of flight MRA) during a 9-month period (April to December 2022). Cases were classified by 4 radiologists in consensus as to whether NeuroMix and NeuroMix + MRA detected equivalent findings, detected unique findings, or missed findings relative to CTAHN.

RESULTS

One hundred seventy-four cases (mean age, 67 [SD, 16] years; 56% female) met the inclusion criteria. NeuroMix alone and NeuroMix + MRA protocols were determined to be equivalent or better compared with CTAHN in 71% and 95% of patients, respectively. NeuroMix always provided equivalent or better assessment of the brain parenchyma, with unique findings on NeuroMix and NeuroMix + MRA in 35% and 36% of cases, respectively, most commonly acute infarction or multiple microhemorrhages. In 8/174 cases (5%), CTAHN identified vascular abnormalities not seen on the NeuroMix + MRA protocol due to the wider coverage of the cervical arteries by CTAHN.

CONCLUSIONS

A fast MR imaging protocol consisting of NeuroMix + MRA provided equivalent or better information compared with CTAHN in 95% of cases in our population of patients with an acute neurologic presentation. The findings provide a deeper understanding of the benefits and challenges of a fast unenhanced MR-first approach with NeuroMix + MRA, which could be used to design prospective trials in select patient groups, with the potential to reduce radiation dose, mitigate adverse contrast-related patient and environmental effects, and lessen the burden on radiologists and health care systems.

Improving the Safety of Computed Tomography Through Automated Quality Measurement: A Radiologist Reader Study of Radiation Dose, Image Noise, and Image Quality

OBJECTIVES

The Centers for Medicare and Medicaid Services funded the development of a computed tomography (CT) quality measure for use in pay-for-performance programs, which balances automated assessments of radiation dose with image quality to incentivize dose reduction without compromising the diagnostic utility of the tests. However, no existing quantitative method for assessing CT image quality has been validated against radiologists' image quality assessments on a large number of CT examinations. Thus to develop an automated measure of image quality, we tested the relationship between radiologists' subjective ratings of image quality with measurements of radiation dose and image noise.

MATERIALS AND METHODS

Board-certified, posttraining, clinically active radiologists rated the image quality of 200 diagnostic CT examinations from a set of 734, representing 14 CT categories. Examinations with significant distractions, motion, or artifact were excluded. Radiologists rated diagnostic image quality as excellent, adequate, marginally acceptable, or poor; the latter 2 were considered unacceptable for rendering diagnoses. We quantified the relationship between ratings and image noise and radiation dose, by category, by analyzing the odds of an acceptable rating per standard deviation (SD) increase in noise or geometric SD (gSD) in dose.

RESULTS

One hundred twenty-five radiologists contributed 24,800 ratings. Most (89%) were acceptable. The odds of an examination being rated acceptable statistically significantly increased per gSD increase in dose and decreased per SD increase in noise for most categories, including routine dose head, chest, and abdomen-pelvis, which together comprise 60% of examinations performed in routine practice. For routine dose abdomen-pelvis, the most common category, each gSD increase in dose raised the odds of an acceptable rating (2.33; 95% confidence interval, 1.98-3.24), whereas each SD increase in noise decreased the odds (0.90; 0.79-0.99). For only 2 CT categories, high-dose head and neck/cervical spine, neither dose nor noise was associated with ratings.

CONCLUSIONS

Radiation dose and image noise correlate with radiologists' image quality assessments for most CT categories, making them suitable as automated metrics in quality programs incentivizing reduction of excessive radiation doses.

Early and Late Effects of Low-Dose X-ray Exposure in Human Fibroblasts: DNA Repair Foci, Proliferation, Autophagy, and Senescence

The effects of low-dose radiation exposure remain a controversial topic in radiation biology. This study compares early (0.5, 4, 24, 48, and 72 h) and late (5, 10, and 15 cell passages) post-irradiation changes in γH2AX, 53BP1, pATM, and p-p53 (Ser-15) foci, proliferation, autophagy, and senescence in primary fibroblasts exposed to 100 and 2000 mGy X-ray radiation. The results show that exposure to 100 mGy significantly increased γH2AX, 53BP1, and pATM foci only at 0.5 and 4 h post irradiation. There were no changes in p-p53 (Ser-15) foci, proliferation, autophagy, or senescence up to 15 passages post irradiation at the low dose.

Utility of Follow-up Radiographs in Type 1 Supracondylar Humerus Fractures

OBJECTIVE

Supracondylar humerus (SCH) fractures are common among pediatric patients, with the severity categorized using the Gartland classification system. Type 1 SCH fractures are nondisplaced and treated with immobilization, while more displaced fractures require surgery. The need for follow-up radiographs, particularly for type 1 fractures, is an area where evidence is lacking. This study investigates the clinical value and financial implications of follow-up radiographs for type 1 SCH fractures, hypothesizing that they do not alter clinical management and, therefore, represent an unnecessary expense.

METHODS

This retrospective cohort study, approved by the Institutional Review Board, focused on patients under 18 with nondisplaced SCH fractures treated nonoperatively. One hundred one type 1 SCH fractures, in which the fracture was visible on presenting radiographs, were chosen from patients presenting between January 2021 and December 2022. Charts were reviewed for demographic information, time of cast removal, and complications. A pediatric orthopaedic surgeon and orthopaedic resident reviewed the radiographs to confirm the injury to be a type 1 SCH fracture.

RESULTS

Among the 101 patients, after the initial presentation, 79 attended an interim visit and 101 attended a "3-week follow-up" at an average of 23 days postinjury. All patients underwent radiographs during these visits for a total of 180 radiographs after confirmation of type 1 SCH fracture. No changes in management resulted from follow-up radiographs. One instance of refracture was noted ~3 months after cast removal. There were 180 superfluous follow-up radiographs taken at subsequent clinic visits. The total charge for these radiographs was $76,001.40, averaging $752.49 per patient.

CONCLUSION

Follow-up radiographs for type 1 SCH fractures did not lead to changes in clinical management, aligning with previous findings in more severe SCH fractures. This approach can reduce costs, radiation exposure, and clinic time without compromising patient care. The study can reassure providers and parents about the lack of necessity for follow-up radiographs to document healing.

LEVEL OF EVIDENCE

Level-IV.

Assessment of medical students' knowledge regarding radiation associated risk and its protection: finding from a cross-sectional study

OBJECTIVE

The current study assessed the knowledge of the medical students regarding the nature of radiation, associated risks, and protective measures.

METHOD

A cross-sectional study was conducted among international students enrolled in different medical colleges/universities in Xian, PR China. A self-developed and self-reported questionnaire was used for the current study. The descriptive statistics was carried out to summarize the finding of the study. Chi-square and Fisher exact tests were conducted to assess the association of the demographics with knowledge level.

RESULTS

A total of 796 students responded among 980. Most of the participants fell in the age range of 20-25 years (42.6%), being male (67.1%) and having bachelor's education (56.7%). Participants with previous experience was 58.7%. The age group of 20-25 years (p < 0.001), being male (p < 0.001), having bachelor education (p < 0.001), and previous experience (p = 0.009) was significantly associated with moderate to good knowledge. The overall knowledge about the nature of radiation (96%) and associated risk (82%) was good, but regarding protection, 59% of the participants showed good knowledge.

CONCLUSION

Most of the participants showed satisfactory result. However, the knowledge regarding protection measures was poor in almost half of the population.

Traumatic Spinal Injury in Children; Time to Revise Pre-Hospital and Diagnostic Protocols?

Background: Traumatic spinal injury in children is a rare but serious life event. Predicting pediatric patients at risk for spinal injury remains difficult. This study focuses on the cause of the injury and predictors to identify children at risk and appropriate diagnostic procedures. Methods: Retrospective chart review from the Landelijke Trauma Registratie of patients with spinal injury from 2010 to 2021 in a level 1 pediatric trauma center. Results: We included 114 children with spinal injury, 79.8% of whom were aged 12-17 years. In the overall trauma population, the incidence of spinal injury was 10% in children aged 12-17 years, 2.3% in children aged 6-11 years, and 0.4% in children 0-5 years of age. Neurological deficits were present in 27.2% of patients in the emergency department, with permanent deficits in 14.0%. Spinal fractures were present in 91.2% of 12-17-year-olds, 43.8% in 6-11-year-olds, and 71.4% in 0-5-year-olds. ISS was 23 (SD 14) in children with spinal injury compared to 8 (SD 9) for children without spinal injury. Conclusions: In children 0-11 years old, spinal injury is very rare compared to the overall trauma population, and there are more non-osseous injuries. Clinicians should consider MRI as the next step after conventional X-ray to diagnose or exclude spinal injuries in this group. In older children aged 12-17 years, the incidence of spinal injury is much higher, at 10%. Although ISS is higher in children with spinal injury, a low ISS does not exclude spinal injury. If one fracture is found, more fractures in other regions of the spine may be present.

Causes of Childhood Cancer: A Review of the Recent Literature: Part I-Childhood Factors

PURPOSE

To review the childhood risk factors for pediatric cancer (diagnosis before age 20).

METHODS

We conducted literature searches using Ovid Medline and Scopus to find primary research studies, review articles, and meta-analyses published from 2014 to 3 March 2021.

RESULTS

Strong evidence indicates that an array of genetic and epigenetic phenomena, structural birth defects, and chromosomal anomalies are associated with an increased risk of various childhood cancers. Increased risk is also associated with prior cancer, likely due to previous treatment agents and therapeutic ionizing radiation. Convincing evidence supports associations between several pediatric cancers and ionizing radiation, immunosuppression, and carcinogenic virus infection both in healthy children and in association with immune suppression following organ transplantation. Breastfeeding and a childhood diet rich in fruits and vegetables appears to reduce the risk of pediatric leukemia but the evidence is less strong. Childhood vaccination against carcinogenic viruses is associated with a lower risk of several cancers; there is less strong evidence that other childhood vaccinations more broadly may also lower risk. Ultraviolet (UV) radiation is associated with increased melanoma risk, although most melanomas following childhood UV exposure occur later, in adulthood. Evidence is weak or conflicting for the role of body mass index, other childhood infections, allergies, and certain treatments, including immunomodulator medications and human growth therapy.

Radioprotective effect of nanoniosome loaded by Mentha Pulegium essential oil on human peripheral blood mononuclear cells exposed to ionizing radiation

OBJECTIVE

The present study aimed to assess the radioprotective effect of nanoniosomes loaded by Mentha Pulegium essential oil (MPEO-N nanoparticles) as a natural antioxidant on human peripheral blood mononuclear cells (PBMCs).

SIGNIFICANCE

Despite the applications and advantages of ionizing radiation, there are many radiation risks to biological systems that are necessary to be reduced as much as possible.

METHODS

MPEO-N nanoparticles were prepared by the lipid thin film hydration method, and its physicochemical characteristics were analyzed. PBMCs were then irradiated with X-ray using a 6 MV linear accelerator at two radiation doses in the presence of nontoxic concentrations of MPEO-N nanoparticles (IC10). After 48 and 72 h of incubation, the radioprotective effect was investigated by measuring survival, apoptosis, and necrosis of PBMCs, using MTT assay and flow cytometry analysis.

KEY FINDINGS

The hydrodynamic diameter and zeta potential of nanoniosomes were 106.0 ± 4.69 nm and -15.2 ± 0.9 mV, respectively. The mean survival percentage of PBMCs showed a significant increase only at a radiation dose of 200 cGy compared with the control group. The percentages of apoptosis and necrosis of cells in the presence of MPEO-N nanoparticles at both radiation doses and incubation periods (48 and 72 h) demonstrated a significant reduction compared with the control.

CONCLUSION

MPEO-N nanoparticles as a natural antioxidant, exhibited a favorable radioprotective effect by a significant reduction in the percentage of apoptosis and necrosis of irradiated PBMCs.

Histological types of brain tumors diagnosed at the Kenyatta National Hospital between 2016 and 2019: a retrospective study

PURPOSE

To determine the histological types of brain tumors diagnosed at the Kenyatta National Hospital, Nairobi, Kenya.

METHODS

This retrospective study retrieved patient-archived records at the Kenyatta National Hospital for the period 2016-2019. The histological types of brain tumors were assessed according to age, sex, and the WHO classification for CNS tumors using the GNU PSPP version 1.6.2-g78a33 software. Results were presented in tables and figures.

RESULTS

During the study period, brain tumors appeared to increase gradually; however, there was a decline in 2018. During the study period, 345 brain tumor records were retrieved. Data on age were missing 33 records; hence, 312 records were included for age analyses. The mean age for the pediatrics and adults was 9 (± 5 SD) and 45 (± 14 SD) years, respectively. 88 (28.2%) and 224 (71.8%) tumors were diagnosed among pediatrics and adults, respectively. Most tumors, 60 (19.2%) were reported in patients aged ≤ 10 years, followed by 55 (17.6%), 48 (15.4%), and 47 (15.1%) in patients aged 31-40, 51-60, and 41-50, years, respectively. In both pediatrics and adults, most tumors were diagnosed in females aged ≤ 10 years and 31-40 years, respectively. Overall, two peaks were observed in patients aged 5-15 years and 40-45 years. Gliomas, 43 (48.9%) and medulloblastomas, 21 (23.9%) were the most common tumors in pediatrics, whereas meningiomas, 107 (47.8%) and gliomas, 70 (31.3%) were the most common tumors in adults. Most pediatric and adult tumors were benign with 50 (56.8%) and 157 (70.1%) cases, respectively. Low-grade gliomas and medulloblastomas were the commonest benign and malignant tumors among pediatrics, with 31 (62%) and 21 (55.3%) cases, respectively. Conversely, meningiomas and high-grade gliomas were the most common benign and malignant tumors in adults, with 106 (67.5%) and 44 (65.7%) cases, respectively.

CONCLUSION

This study highlights the existing burden of brain tumors in Kenya and data from KNH may be representative of the national burden of BTs. This study lays a foundation for subsequent clinical and epidemiological studies and emphasizes the need to adopt existing reporting standards to help realize a complete picture of the burden of brain tumors in Kenya.

Non-Habit-Related Oral Squamous Cell Carcinoma: A Review

Oral squamous cell carcinoma (OSCC) is a serious and potentially life-threatening condition that can have a profound impact on an individual's health and well-being. Its etiology is commonly known to be habit induced, such as tobacco consumption, smoking, or alcohol abuse. Apart from these etiologies, certain factors that lead to OSCC are also present but are less frequently encountered in hospitals and clinics. However, these non-habitual factors, with their pathogenesis, can lead to OSCC, which may be confusing to certain medical practitioners. This article discusses the various non-habitual causes that can lead to OSCC, as well as their pathophysiology, molecular expression, and related indicators and prognostic factors.

Pediatric Ultrasound Appendicitis Score for the Diagnosis of Acute Appendicitis to Reduce Computed Tomography Scan Utilization

BACKGROUND

Acute appendicitis is one of the most common reasons for pediatric surgical consultation in the emergency room. Although acute appendicitis is a clinical diagnosis, the use of imaging in the emergency department to assist with the diagnosis is very common. Ultrasound is frequently utilized in pediatrics because of the radiation risks associated with computed tomography (CT) scan. The risks of radiation in the pediatric population are much more significant than in adults. Reasons for this include smaller size so there is a relative higher radiation dose than for larger adults, radiosensitive organs such as thyroid, bone marrow, and gonads, and radiation exposure earlier in life allows for more time that a radiation induced cancer could develop. The risks of radiation from imaging are increased with cumulative dosing.

METHODS

The purpose of this study was to incorporate the pediatric appendicitis score (PAS) and standardized ultrasound scoring system to provide a combined score that would assist with the clinical diagnosis of acute appendicitis and avoid the need for a CT scan.

RESULTS

The presented data shows that for scores of 7 or more, the specificity and sensitivity is 90% and 90.2%, respectively for the diagnosis of acute appendicitis.

DISCUSSION

This study validates the combined score, shows the specific cutoffs, and initiates the discussion that CT scan may not always be required for diagnosing acute appendicitis if this scoring system is used.

CanCHD Study of Hematopoietic Cancers in Children With and Without Genetic Syndromes

BACKGROUND

Individuals with genetic syndromes can manifest both congenital heart disease (CHD) and cancer attributable to possible common underlying pathways. To date, reliable risk estimates of hematopoietic cancer (HC) among children with CHD based on large population-based data remain scant. This study sought to quantify the risk of HC by the presence of genetic syndrome among children with CHD.

METHODS AND RESULTS

Data sources were the Canadian CHD database, a nationwide database on CHD (1999-2017), and the CCR (Canadian Cancer Registry). Standardized incidence ratios were calculated for comparing HC incidences in children with CHD with the general pediatric population. A modified Kaplan-Meier curve was used to estimate the cumulative incidence of HC with death as a competing risk. A total of 143 794 children (aged 0-17 years) with CHD were followed up from birth to age 18 years for 1 314 603 person-years. Of them, 8.6% had genetic syndromes, and 898 HC cases were observed. Children with known syndromes had a substantially higher risk of incident HC than the general pediatric population (standardized incidence ratio, 13.4 [95% CI, 11.7-15.1]). The cumulative incidence of HC was 2.44% (95% CI, 2.11-2.76) among children with a syndrome and 0.79% (95% CI, 0.72-0.87) among children without a syndrome. Acute myeloid leukemia had a higher cumulative incidence during early childhood than acute lymphoblastic leukemia.

CONCLUSIONS

This is the first large population-based analysis documenting that known genetic syndromes in children with CHD are a significant predictor of HC. The finding could be essential in informing risk-stratified policy recommendations for cancer surveillance in children with CHD.

Has fluoroless endourology (URS and PCNL) come of age? Evidence from a comprehensive literature review

INTRODUCTION

Radiation via the use of imaging is a key tool in management of kidney stones. Simple measures are largely taken by the endourologists to implement the 'As Low As Reasonably Achievable' (ALARA) principle, including the use of fluoroless technique. We performed a scoping literature review to investigate the success and safety of fluoroless ureteroscopy (URS) or percutaneous nephrolithotomy (PCNL) procedures for the treatment of KSD.

METHODS

A literature review was performed searching bibliographic databases PubMed, EMBASE and Cochrane library, and 14 full papers were included in the review in accordance with the PRISMA guidelines.

RESULTS

Of the 2535 total procedures analysed, 823 were fluoroless URS vs. 556 fluoroscopic URS; and 734 fluoroless PCNL vs. 277 fluoroscopic PCNL. The SFR for fluoroless vs. fluoroscopic guided URS was 85.3% and 77%, respectively (p=0.2), while for fluoroless PCNL vs. fluoroscopic group was 83.8% and 84.6%, respectively (p=0.9). The overall Clavien-Dindo I/II and III/IV complications for fluoroless and fluoroscopic guided procedures were 3.1% (n=71) and 8.5% (n=131), and 1.7% (n=23) and 3% (n=47) respectively. Only 5 studies reported a failure of the fluoroscopic approach with a total of 30 (1.3%) failed procedures.

CONCLUSION

The ALARA protocol has been implemented in endourology in numerous ways to protect both patients and healthcare workers during recent years. Fluoroless procedures for treatment of KSD are safe and effective with outcomes comparable to standard procedures and could become the new frontier of endourology in selected cases.

Early Preventive Strategies and CNS Meningioma - Is This Feasible? A Comprehensive Review of the Literature

BACKGROUND

Meningiomas are one of the most common benign primary brain tumors; however, there is a paucity of literature on potential preventability. This comprehensive review aimed to explore the existing evidence for the potential risk factors that may contribute to meningioma development and to discuss early prevention strategies.

METHODS

Literature search was conducted via MEDLINE, Embase, Web of Science, and Cochrane Database to retrieve existing literature on various environmental exposures and lifestyle behaviors that are potential risk factors for the development of meningiomas.

RESULTS

Significant risk factors included exposure to ionizing radiation and certain environmental chemicals. Notably, this study also identified that cigarette smoking and obesity are associated with the development of meningiomas. To date, wireless phone usage, hormonal exposures, dietary factors, and traumatic brain injury remain inconclusive. Early prevention strategies should primarily be family-driven, community-based, and public health-endorsed strategies. Targeting unhealthy behaviors through healthcare organizations could execute a pivotal role in the maintenance of an optimum lifestyle, reducing the development of risk factors pertinent to meningiomas.

CONCLUSIONS

To our knowledge, this is the first study that offers a perspective on prevention of meningiomas. A causal relationship of risk factors in developing meningiomas cannot be directly established with the current evidence. We are aware of the limitations of the hypothesis, but we believe that this study will raise more awareness and our findings could potentially be endorsed by organizations promoting health across the globe. Further prospective and retrospective studies will shed more light on this topic and help establish a definitive relationship.

Novel NIR-II fluorescent probes for biliary atresia imaging

Biliary atresia is a rare infant disease that predisposes patients to liver transplantation and death if not treated in time. However, early diagnosis is challenging because the clinical manifestations and laboratory tests of biliary atresia overlap with other cholestatic diseases. Therefore, it is very important to develop a simple, safe and reliable method for the early diagnosis of biliary atresia. Herein, a novel NIR-II fluorescence probe, HZL2, with high quantum yield, excellent biocompatibility, low cytotoxicity and rapid excretion through the liver and gallbladder was developed based on the oil/water partition coefficient and permeability. A simple fecal sample after injection of HZL2 can be used to efficiently identify the success of the mouse model of biliary atresia for the first time, allowing for an early diagnosis of the disease. This study not only developed a simple and safe method for the early diagnosis of biliary atresia with great potential in clinical translation but also provides a research tool for the development of pathogenesis and therapeutic medicines for biliary atresia.

Revising and exploring the variations in methodologies for establishing the diagnostic reference levels for paediatric PET/CT imaging

PET-computed tomography (PET/CT) is a hybrid imaging technique that combines anatomical and functional information; to investigate primary cancers, stage tumours, and track treatment response in paediatric oncology patients. However, there is debate in the literature about whether PET/CT could increase the risk of cancer in children, as the machine is utilizing two types of radiation, and paediatric patients have faster cell division and longer life expectancy. Therefore, it is essential to minimize radiation exposure by justifying and optimizing PET/CT examinations and ensure an acceptable image quality. Establishing diagnostic reference levels (DRLs) is a crucial quantitative indicator and effective tool to optimize paediatric imaging procedures. This review aimed to distinguish and acknowledge variations among published DRLs for paediatric patients in PET/CT procedures. A search of relevant articles was conducted using databases, that is, Embase, Scopus, Web of Science, and Medline, using the keywords: PET-computed tomography, computed tomography, PET, radiopharmaceutical, DRL, and their synonyms. Only English and full-text articles were included, with no limitations on the publication year. After the screening, four articles were selected, and the review reveals different DRL approaches for paediatric patients undergoing PET/CT, with primary variations observed in patient selection criteria, reporting of radiation dose values, and PET/CT equipment. The study suggests that future DRL methods for paediatric patients should prioritize data collection in accordance with international guidelines to better understand PET/CT dose discrepancies while also striving to optimize radiation doses without compromising the quality of PET/CT images.

The pregnant traveller: An overview of general travel advice

Travel during pregnancy is common, but is associated with a number of risks and potential problems. There are many pregnancy-specific and destination-specific issues to be considered along with issues related to method of transport. Travel experiences should be made as safe as possible through evidence-based counselling via pregnancy healthcare providers prior to travel. This travelling in pregnancy article has been created to facilitate pregnancy healthcare providers in having these pre-travel discussions to optimise maternal and fetal wellbeing.

Medical imaging utilization and associated radiation exposure in children with down syndrome

OBJECTIVE

To evaluate the frequency of medical imaging or estimated associated radiation exposure in children with Down syndrome.

METHODS

This retrospective cohort study included 4,348,226 children enrolled in six U.S. integrated healthcare systems from 1996-2016, 3,095 of whom were diagnosed with Down syndrome. We calculated imaging rates per 100 person years and associated red bone marrow dose (mGy). Relative rates (RR) of imaging in children with versus without Down syndrome were estimated using overdispersed Poisson regression.

RESULTS

Compared to other children, children with Down syndrome received imaging using ionizing radiation at 9.5 times (95% confidence interval[CI] = 8.2-10.9) the rate when age <1 year and 2.3 times (95% CI = 2.0-2.5) between ages 1-18 years. Imaging rates by modality in children <1 year with Down syndrome compared with other children were: computed tomography (6.6 vs. 2.0, RR = 3.1[95%CI = 1.8-5.1]), fluoroscopy (37.1 vs. 3.1, RR 11.9[95%CI 9.5-14.8]), angiography (7.6 vs. 0.2, RR = 35.8[95%CI = 20.6-62.2]), nuclear medicine (6.0 vs. 0.6, RR = 8.2[95% CI = 5.3-12.7]), radiography (419.7 vs. 36.9, RR = 11.3[95%CI = 10.0-12.9], magnetic resonance imaging(7.3 vs. 1.5, RR = 4.2[95% CI = 3.1-5.8]), and ultrasound (231.2 vs. 16.4, RR = 12.6[95% CI = 9.9-15.9]). Mean cumulative red bone marrow dose from imaging over a mean of 4.2 years was 2-fold higher in children with Down syndrome compared with other children (4.7 vs. 1.9mGy).

CONCLUSIONS

Children with Down syndrome experienced more medical imaging and higher radiation exposure than other children, especially at young ages when they are more vulnerable to radiation. Clinicians should consider incorporating strategic management decisions when imaging this high-risk population.

Gamma radiation detector selection for CT scanner

Three types of gamma radiation detectors associated with distributed electronics namely, NaI (Tl), HPGe and LaBr3(Ce) are compared primarily focusing on electronic noise and scattering noise. Additionally, detectors of same make, material, size and electronics are also compared. A methodology is proposed to select the most suitable detector for computed tomography (CT) among the available options. Standard deviation parameter is employed to estimate electronic noise without performing CT experiment. Kanpur theorem-1(KT-1) is used to estimate the scattering noise quantitatively after verifying its sensitivity to scattering noise. The impact of scattering noise on CT profiles is evaluated using dice similarity dice coefficient. A good resemblance between KT-1 and dice coefficient is observed. A maximum difference of 56% in scattering noise is observed when five detectors used simultaneously instead of single detector whereas a discrepancy of 85% is observed between different types of radiation detectors. As far as ease of handling, operational and capital cost is concern one has to compromise minimum 12% of accuracy in CT reconstruction if NaI (Tl) detector is used with respect to best alternative available. The proposed methodology can be applied to measurement that require minimal scattering interference data other than CT experiments. The manufacturer can add noise level of detector as a characteristic parameter in the data sheet.

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.

The scientific basis for the use of the linear no-threshold (LNT) model at low doses and dose rates in radiological protection

The linear no-threshold (LNT) model was introduced into the radiological protection system about 60 years ago, but this model and its use in radiation protection are still debated today. This article presents an overview of results on effects of exposure to low linear-energy-transfer radiation in radiobiology and epidemiology accumulated over the last decade and discusses their impact on the use of the LNT model in the assessment of radiation-related cancer risks at low doses. The knowledge acquired over the past 10 years, both in radiobiology and epidemiology, has reinforced scientific knowledge about cancer risks at low doses. In radiobiology, although certain mechanisms do not support linearity, the early stages of carcinogenesis comprised of mutational events, which are assumed to play a key role in carcinogenesis, show linear responses to doses from as low as 10 mGy. The impact of non-mutational mechanisms on the risk of radiation-related cancer at low doses is currently difficult to assess. In epidemiology, the results show excess cancer risks at dose levels of 100 mGy or less. While some recent results indicate non-linear dose relationships for some cancers, overall, the LNT model does not substantially overestimate the risks at low doses. Recent results, in radiobiology or in epidemiology, suggest that a dose threshold, if any, could not be greater than a few tens of mGy. The scientific knowledge currently available does not contradict the use of the LNT model for the assessment of radiation-related cancer risks within the radiological protection system, and no other dose-risk relationship seems more appropriate for radiological protection purposes.

Experimental mouse models for translational human cancer research

The development and growth of tumors remains an important and ongoing threat to human life around the world. While advanced therapeutic strategies such as immune checkpoint therapy and CAR-T have achieved astonishing progress in the treatment of both solid and hematological malignancies, the malignant initiation and progression of cancer remains a controversial issue, and further research is urgently required. The experimental animal model not only has great advantages in simulating the occurrence, development, and malignant transformation mechanisms of tumors, but also can be used to evaluate the therapeutic effects of a diverse array of clinical interventions, gradually becoming an indispensable method for cancer research. In this paper, we have reviewed recent research progress in relation to mouse and rat models, focusing on spontaneous, induced, transgenic, and transplantable tumor models, to help guide the future study of malignant mechanisms and tumor prevention.

Comprehensive Neonatal Cardiac, Feed and Wrap, Non-contrast, Non-sedated, Free-breathing Compressed Sensing 4D Flow MRI Assessment

BACKGROUND

Cardiac MRI is an important imaging tool in congenital cardiac disease, but its use has been limited in the neonatal population as general anesthesia has been needed for breath-holding. Technological advances in four-dimensional (4D) flow MRI have now made nonsedated free-breathing acquisition protocols a viable clinical option, but the method requires prospective validation in neonates.

PURPOSE

To test the feasibility of compressed sensing (CS) 4D flow MRI in the neonatal population and to compare with standard previously validated two-dimensional (2D) phase-contrast (PC) flow MRI.

STUDY TYPE

Prospective, cohort, image quality.

POPULATION

A total of 14 healthy neonates (median [range] age: 2.5 [0-80] days; 8 male).

FIELD STRENGTH AND SEQUENCE

Noncontrast 2D cine gradient echo sequence with through-plane velocity encoding (PC) sequence and compressed sensing (CS) three-dimensional (3D), time-resolved, cine phase-contrast MRI with 3D velocity-encoding (4D flow MRI) at 3 T.

ASSESSMENT

Aortic 2D PC, and aortic, pulmonary trunk and superior vena cava CS 4D flow MRI were acquired using the feed and wrap technique (nonsedated) and quantified using commercially available software. Aortic flow and peak velocity were compared between methods. Internal consistency of 4D flow MRI was determined by comparing mean forward flow of the main pulmonary artery (MPA) vs. the sum of left and right pulmonary artery flows (LPA and RPA) and by comparing mean ascending aorta forward flow (AAo) vs. the sum of superior vena cava (SVC) and descending aorta flows (DAo).

STATISTICAL TESTS

Flow and peak-velocity comparisons were assessed using paired t-tests, with P < 0.05 considered significant, and Bland-Altman analysis. Interobserver and intraobserver agreement and internal consistency were analyzed by intraclass correlation co-efficient (ICC).

RESULTS

There was no statistically significant difference between ascending aortic forward flow between 2D PC and CS 4D Flow MRI (P = 0.26) with a bias of 0.11 mL (-0.59 to 0.82 mL) nor peak velocity (P = 0.11), with a bias of -5 cm/sec and (-26 to 16 cm/sec). There was excellent interobserver and intraobserver agreement for each vessel (interobserver ICC: AAo 1.00; DAo 0.94, SVC 0.90, MPA 0.99, RPA 0.98, LPA 0.96; intraobserver ICC: AAo 1.00; DAo 0.99, SVC 0.98, MPA 1.00, RPA 1.00, LPA 0.99). Internal consistency measures showed excellent agreement for both mean forward flow of main pulmonary artery vs. the sum of left and right pulmonary arteries (ICC: 0.95) and mean ascending aorta forward flow vs. the sum of superior vena cava and descending aorta flows (ICC: 1.00).

CONCLUSION

Sedation-free neonatal feed and wrap MRI is well tolerated and feasible. CS 4D flow MRI quantification is similar to validated 2D PC free-breathing imaging with excellent interobserver and intraobserver agreement.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

The why, who, how, and what of communicating CT radiation risks to patients and healthcare providers

Computed tomography (CT) has witnessed tremendous growth in utilization. Despite its immense benefits, there is a growing concern from the general public and the medical community about the detrimental consequences of ionizing radiation from CT. Anxiety from the perceived risks associated with CT can deter referring physicians from ordering clinically indicated CT scans and patients from undergoing medically necessary exams. This article discusses various strategies for educating patients and healthcare providers on the benefits and risks of CT scanning and salient techniques for effective communication.

A systematic review and meta-analysis of computed tomography in the diagnosis of pediatric foreign body aspiration

INTRODUCTION

Rigid bronchoscopy remains the gold standard for the diagnosis of foreign body aspiration (FBA) despite high rates of negative bronchoscopies. The use of computed tomography (CT) imaging in the assessment of FBA has recently emerged and could help obviate unnecessary bronchoscopy in these patients. The aim of this study is to assess the diagnostic accuracy of CT in the diagnosis of pediatric FBA.

METHODS

A systematic literature review was conducted to identify studies reporting the use of CT imaging in suspected pediatric FBA. The search included published articles in Ovid MEDLINE, Ovid EMBASE, PubMed MEDLINE and Web of Science. The search strategy included all articles from inception of the database to January 2021. Manuscripts were reviewed and graded for quality using the QUADAS-2 tool. Subgroup analyses based on the use of virtual bronchoscopy (VB) and sedation was conducted. A meta-analysis evaluating the use of VB in the diagnosis of FBA was also conducted.

RESULTS

Sixteen manuscripts met all inclusion criteria. In total, 2056 pediatric patients ranging from 0.3 to 15 years underwent CT for suspected FBA. The sensitivity and specificity of CT were 98.8% and 96.6%, respectively. VB was used in 71.4% (1391/1948) of patients while sedation during CT was required in 70.2% (1263/1800) of patients. Radiation dosing ranged from 0.04 to 2 mSv, 0.99-59.1 mGy-cm and 0.03-16.99 mGy.

CONCLUSION

CT can accurately diagnose pediatric FBA and can help decrease the rate of unnecessary bronchoscopies with an acceptable dose of radiation.

An introduction to photon-counting detector CT (PCD CT) for radiologists

The basic performance of photon-counting detector computed tomography (PCD CT) is superior to conventional CT (energy-integrating detector CT: EID CT) because its spatial- and contrast resolution of soft tissues is higher, and artifacts are reduced. Because the X-ray photon energy separation is better with PCD CT than conventional EID-based dual-energy CT, it has the potential to improve virtual monochromatic- and virtual non-contrast images, material decomposition including quantification of the iodine distribution, and K-edge imaging. Therefore, its clinical applicability may be increased. Although the image quality of PCD CT scans is superior to that of EID CT currently, further improvement may be possible. The introduction of iterative image reconstruction and reconstruction with deep convolutional neural networks will be useful.

Risk of various cancers in adults with abdominal aortic aneurysms

BACKGROUND

The cause of death for patients with an abdominal aortic aneurysm (AAA) can be related to the AAA itself. However, cancer-related mortality could also be a contributing factor. In the present study, we examined the hypothesis that an association exists between AAAs and certain cancers.

METHODS

Information from 2009 to 2015 was extracted from the Korean National Health Insurance Service database. We included 14,920 participants with a new diagnosis of an AAA. Propensity score matching by age and sex with disease-free patients was used to select the control group of 44,760 participants. The primary end point of the present study was a new diagnosis of various cancers.

RESULTS

The hazard ratio (HR) for cancer incidence was higher in the AAA group than in the control group for hepatoma, pancreatic cancer, and lung cancer (HR, 1.376, 1.429, and 1.394, respectively). In the case of leukemia, the HR for cancer occurrence was not significantly higher in the AAA group than in the control group. However, when stratified by surgery, the HR was significantly higher for the surgical group (HR, 3.355), especially for endovascular aneurysm repair (HR, 3.864).

CONCLUSIONS

We found that AAAs are associated with an increased risk of cancer, in particular, hepatoma, pancreatic cancer, and lung cancer, even after adjusting for several comorbidities. Thus, continued follow-up is necessary for patients with an AAA to permit the early detection of the signs and symptoms of cancer.

[Imaging after trauma in clinics and practice for children and adolescents : Part 1 of the results of a nationwide online survey of the Pediatric Traumatology Section of the German Trauma Society]

BACKGROUND

The indication for radiography should strictly follow the ALARA (as low as reasonably achievable) principle in pediatric and adolescent trauma patients. The effect of radiation on the growing sensitive tissue of these patients should not be disregarded.

QUESTION

The Pediatric Traumatology Section (SKT) of the German Trauma Society (DGU) wanted to clarify how the principle is followed in trauma care.

METHODS

An online survey was open for 10 weeks. Target groups were trauma surgeons, pediatric surgeons, general surgeons, and orthopedic surgeons.

RESULTS

From Nov. 15, 2019, to Feb. 29, 2020, 788 physicians participated: branch office 20.56%, MVZ 4.31%, hospital 75.13%; resident 16.62%, senior 38.07%, chief 22.59%. By specialist qualification, the distribution was: 38.34% surgery, 33.16% trauma surgery, 36.66% special trauma surgery, 70.34% orthopedics and trauma surgery, 18.78% pediatric surgery. Frequency of contact with fractures in the above age group was reported as 37% < 10/month, 27% < 20/M, 36% > 20/M. About 52% always request radiographs in 2 planes after acute trauma. X-ray of the opposite side for unclear findings was rejected by 70%. 23% use sonography regularly in fracture diagnosis. In polytrauma children and adolescents, whole-body CT is never used in 18%, rarely in 50%, and standard in 14%.

DISCUSSION

The analysis shows that there is no uniform radiological management of children and adolescents with fractures among the respondents.

CONCLUSION

Comparing the results of the survey with the consensus findings of the SKT recently published in this journal, persuasion is still needed to change the use of radiography in primary diagnosis.

Radiation Exposure and Lifetime Attributable Risk of Cancer Incidence and Mortality from Low- and Standard-Dose CT Chest: Implications for COVID-19 Pneumonia Subjects

Since the novel coronavirus disease 2019 (COVID-19) outbreak, there has been an unprecedented increase in the acquisition of chest computed tomography (CT) scans. Nearly 616 million people have been infected by COVID-19 worldwide to date, of whom many were subjected to CT scanning. CT exposes the patients to hazardous ionizing radiation, which can damage the genetic material in the cells, leading to stochastic health effects in the form of heritable genetic mutations and increased cancer risk. These probabilistic, long-term carcinogenic effects of radiation can be seen over a lifetime and may sometimes take several decades to manifest. This review briefly describes what is known about the health effects of radiation, the lowest dose for which there exists compelling evidence about increased radiation-induced cancer risk and the evidence regarding this risk at typical CT doses. The lifetime attributable risk (LAR) of cancer from low- and standard-dose chest CT scans performed in COVID-19 subjects is also discussed along with the projected number of future cancers that could be related to chest CT scans performed during the COVID-19 pandemic. The LAR of cancer Incidence from chest CT has also been compared with those from other radiation sources, daily life risks and lifetime baseline risk.

Nanoscale biomaterials for terahertz imaging: A non-invasive approach for early cancer detection

Terahertz (THz) technology is developing a non-invasive imaging system for biosensing and clinical diagnosis. THz medical imaging mainly benefits from great sensitivity in detecting changes in water content and structural variations in diseased cells versus normal tissues. Compared to healthy tissues, cancerous tumors contain a higher level of water molecules and show structural changes, resulting in different THz absorption. Here we described the principle of THz imaging and advancement in the field of translational biomedicine and early detection of pathologic tissue, with a particular focus on oncology. In addition, although the main forte of THz imaging relies on detecting differences in water content to distinguish the exact margin of tumor, THz displays limited contrast in living tissue for in-vivo clinical imaging. In the last few years, nanotechnology has attracted attention to aid THz medical imaging and various nanoparticles have been investigated as contrast enhancements to improve the accuracy, sensitivity, and specificity of THz images. Most of these multimodal contrast agents take advantage of the temperature-dependent of THz spectrum to the conformational variation of the water molecule. We discuss advances in developing THz contrast agents to accelerate the advancement of non-invasive THz imaging with improved sensitivity and specificity for translational clinical oncology.

A case report on ultrasound evaluation of pediatric post-operative abdominal pain

Pediatric post-operative abdominal pain can present a unique diagnostic challenge. The case presented here describes a 9-year-old female who presented with fever and worsening abdominal pain 4 days after laparoscopic resection of a benign ovarian teratoma. Computed tomography failed to provide adequate diagnostic imaging. Ultrasound was subsequently used to rule-out a major post-operative complication and ultimately led to a successful non-operative approach while avoiding repeat radiation exposure. Thin body habitus, increased radiosensitivity of pediatric organs, and increased lifetime risk of cancer complicate the use of computed tomography in the pediatric population. Ultrasound, when correlated to clinical findings, has unique advantages over CT such as detailed delineation of soft tissue structures and dynamic assessment of anatomy that make it advantageous in the pediatric post-operative setting.

Barriers and facilitators of CT scan reduction in the workup of pediatric appendicitis: A pediatric surgical quality collaborative qualitative study

INTRODUCTION

Despite ongoing efforts to decrease ionizing radiation exposure from computed tomography (CT) use in pediatric appendicitis, high CT utilization rates are still observed across many hospitals. This study aims to identify factors influencing CT use and facilitators and barriers to quality improvement efforts.

METHODS

The Pediatric Surgery Quality Collaborative is a voluntary consortium of 42 children's hospitals participating in the National Surgical Quality Improvement Project - Pediatric. Hospitals were compared based on CT utilization from January 1, 2019, to December 31, 2019. Semi-structured interviews were conducted with surgeons, radiologists, emergency medicine physicians, and clinical data abstractors from 7 hospitals with low CT use rates (high performers) and 6 hospitals with high CT use rates (low performers). A mixed deductive and inductive coding approach for analysis of the interview transcripts was used to develop a codebook based on the Theoretical Domains Framework and subsequently identify prominent barriers and facilitators to CT reduction.

RESULTS

Thematic saturation was achieved after 13 interviews. We identified four factors that distinguish high-performing from low-performing hospitals: (1) consistent availability of resources such as ultrasound technicians, pediatric radiologists, and magnetic resonance imaging (MRI); (2) presence of and adherence to protocols guiding imaging modality decision making and imaging execution; (3) culture of inter-departmental collaboration; and (4) presence of a radiation reduction champion.

CONCLUSIONS

Significant barriers to reducing the use of CT in pediatric appendicitis exist. Our findings highlight that future quality improvement efforts should target resource availability, protocol adherence, collaborative culture, and radiation reduction champions.

LEVELS OF EVIDENCE

Level III.

Radiation dose rate effects: what is new and what is needed?

Despite decades of research to understand the biological effects of ionising radiation, there is still much uncertainty over the role of dose rate. Motivated by a virtual workshop on the "Effects of spatial and temporal variation in dose delivery" organised in November 2020 by the Multidisciplinary Low Dose Initiative (MELODI), here, we review studies to date exploring dose rate effects, highlighting significant findings, recent advances and to provide perspective and recommendations for requirements and direction of future work. A comprehensive range of studies is considered, including molecular, cellular, animal, and human studies, with a focus on low linear-energy-transfer radiation exposure. Limits and advantages of each type of study are discussed, and a focus is made on future research needs.

Pediatric Cancer By Race, Ethnicity and Region in the United States

BACKGROUND

In a 2018 descriptive study, cancer incidence in children (age 0-19) in diagnosis years 2003 to 2014 was reported as being highest in New Hampshire and in the Northeast region.

METHODS

Using the Cancer in North America (CiNA) analytic file, we tested the hypotheses that incidence rates in the Northeast were higher than those in other regions of the United States either overall or by race/ethnicity group, and that rates in New Hampshire were higher than the Northeast region as a whole.

RESULTS

In 2003 to 2014, pediatric cancer incidence was significantly higher in the Northeast than other regions of the United States overall and among non-Hispanic Whites and Blacks, but not among Hispanics and other racial minorities. However, there was no significant variability in incidence in the states within the Northeast overall or by race/ethnicity subgroup. Overall, statistically significantly higher incidence was seen in the Northeast for lymphomas [RR, 1.15; 99% confidence interval (CI), 1.10-1.19], central nervous system neoplasms (RR, 1.12; 99% CI, 1.07-1.16), and neuroblastoma (RR, 1.13; 99% CI, 1.05-1.21).

CONCLUSIONS

Pediatric cancer incidence is statistically significantly higher in the Northeast than in the rest of the United States, but within the Northeast, states have comparable incidence. Differences in cancer subtypes by ethnicity merit further investigation.

IMPACT

Our analyses clarify and extend previous reports by statistically confirming the hypothesis that the Northeast has the highest pediatric cancer rates in the country, by providing similar comparisons stratified by race/ethnicity, and by assessing variability within the Northeast.

Ionizing radiation exposure during adulthood and risk of developing central nervous system tumors: systematic review and meta-analysis

Many studies on ionizing radiation (IR) exposure during childhood have shown deleterious effects on the central nervous system (CNS), however results regarding adult exposure are inconsistent, and no systematic reviews have been performed. The objectives are to synthesize the findings and draw evidence-based conclusions from epidemiological studies on the risk of benign and malignant brain and CNS tumors in humans exposed to low-to-moderate doses (< 0.5 Gy) of IR during adulthood/young adulthood. A systematic literature search of four electronic databases, supplemented by a hand search, was performed to retrieve relevant epidemiological studies published from 2000 to 2022. Pooled excess relative risk (ERRpooled) was estimated using a random effect model. Eighteen publications were included in the systematic review and twelve out of them were included in a meta-analysis. The following IR sources were considered: atomic bombs, occupational, and environmental exposures. No significant dose-risk association was found for brain/CNS tumors (ERRpooled at 100 mGy = - 0.01; 95% CI: - 0.05, 0.04). Our systematic review and meta-analysis did not show any association between exposure to low-to-moderate doses of IR and risk of CNS tumors. Further studies with histological information and precise dose assessment are needed.

Guidelines for Cancer Treatment during Pregnancy: Ethics-Related Content Evolution and Implications for Clinicians

(1) Background: Current scientific evidence suggests that most cancers, including breast cancer, can be treated during pregnancy without compromising maternal and fetal outcomes. This, however, raises questions regarding the ethical implications of clinical care. (2) Methods: Using a systematic literature search, 32 clinical practice guidelines for cancer treatment during pregnancy published between 2002 and 2021 were selected for analysis and 25 of them mentioned or made references to medical ethics when offering clinical management guidance for clinicians. (3) Results: Four bioethical themes were identified: respect for patient's autonomy, balanced approach to maternal and fetal beneficence, protection of the vulnerable and justice in resource allocation. Most guidelines recommended informing the pregnant patient about available evidence-based treatment options, offering counselling and support in the process of decision making. The relational aspect of a pregnant patient's autonomy was also recognized and endorsed in a significant number of available guidelines. (4) Conclusions: Recognition and support of a patient's autonomy and its relational aspects should remain an integral part of future clinical practice guidelines. Nevertheless, a more structured approach is needed when addressing existing and potential ethical issues in clinical practice guidelines for cancer treatment during pregnancy.

Cancer risks among studies of medical diagnostic radiation exposure in early life without quantitative estimates of dose

BACKGROUND

There is accumulating evidence of excess risk of cancer in various populations exposed at acute doses below several tens of mSv or doses received over a protracted period. There is also evidence that relative risks are generally higher after radiation exposures in utero or in childhood.

METHODS AND FINDINGS

We reviewed and summarised evidence from 89 studies of cancer following medical diagnostic exposure in utero or in childhood, in which no direct estimates of radiation dose are available. In all of the populations studied exposure was to sparsely ionizing radiation (X-rays). Several of the early studies of in utero exposure exhibit modest but statistically significant excess risks of several types of childhood cancer. There is a highly significant (p < 0.0005) negative trend of odds ratio with calendar period of study, so that more recent studies tend to exhibit reduced excess risk. There is no significant inter-study heterogeneity (p > 0.3). In relation to postnatal exposure there are significant excess risks of leukaemia, brain and solid cancers, with indications of variations in risk by cancer type (p = 0.07) and type of exposure (p = 0.02), with fluoroscopy and computed tomography scans associated with the highest excess risk. However, there is highly significant inter-study heterogeneity (p < 0.01) for all cancer endpoints and all but one type of exposure, although no significant risk trend with calendar period of study.

CONCLUSIONS

Overall, this large body of data relating to medical diagnostic radiation exposure in utero provides support for an associated excess risk of childhood cancer. However, the pronounced heterogeneity in studies of postnatal diagnostic exposure, the implied uncertainty as to the meaning of summary measures, and the distinct possibilities of bias, substantially reduce the strength of the evidence from the associations we observe between radiation imaging in childhood and the subsequent risk of cancer being causally related to radiation exposure.

The Potential of S100 Calcium-Binding Protein B and Glial Fibrillary Acid Protein in Predicting the Intracranial Lesions in Mild Traumatic Brain Injury: A Systematic Review of Literature

ABSTRACT AIM: To summarize the current evidence of S100B and GFAP in predicting intracranial lesions after mTBI. MATERIAL AND METHODS: We searched publications on biomarkers in mTBI from Web of Science, PubMed, and Scopus between January 1990 and July 2021. We included RCTs, cohort, case control, and cross-sectional studies that involved patients with acute closed mTBI in all age group in which head CT scan and blood-based biomarkers (GFAP and S100B) examination were conducted under 24 hours. This study was registered in Open Science Framework. RESULTS: The initial search identified 4.937 article, in which 127 were included for full-text assessment. A total of 16 articles were finally included. No RCT was found in literature searching. Thirteen studies were studying S100B and three studies were studying GFAP. Nine out of 13 S100B studies shows a promising result with ≥ 95% sensitivity for detecting intracranial lesions.  Majorities (11 /13) studies of  S100B confirmed that S100B reduced the unnecessary usage of CT scan. GFAP concentration significantly increased in CT+ patient than CT- patient. No specific GFAP cut off value between the studies was found. CONCLUSION: The result showed that S100B and GFAP had potential to predict the occurrence of intracranial lesions. Variance between methodologies and cut off value hindered the quality of evidence, especially in GFAP. KEYWORDS: mild traumatic brain injury, S100B, GFAP.

Learning Curve and Initial Outcomes of Full-Endoscopic Posterior Lumbar Interbody Fusion

Study Design

This was a retrospective cohort study.

Objective

We evaluated the feasibility, safety, and accuracy of full-endoscopic posterior lumbar interbody fusion (FE-PLIF) by assessing the learning curve and initial clinical outcomes.

Summary of Background Data

Low back pain is one of the crucial medical conditions worldwide. FE-PLIF has been reported to be a minimally invasive method to treat mechanical low back pain, but there lacks a thorough evaluation on this new technique.

Methods

The patients were divided into three groups in the order of operating date, implying that Group A consisted of the initial 12 cases, Group B the subsequent 12 cases, and Group C the last 12 cases. The data of patients were reviewed for gender, age, preoperative symptoms, satisfaction, as well as clinical outcomes demonstrated by visual analog scale (VAS). The operative time and intraoperative fluoroscopy were recorded to demonstrate the learning curve and the extent of radiographic exposure. Statistical significance was set at a p &lt; 0.05 (two-sided).

Results

The patients enrolled in this study were followed up at an average of 1.41 ± 0.24 years. Overall, patients were satisfied with the surgery. The average number of intraoperative fluoroscopy was 6.97 ± 0.74. A significant improvement was observed in the VAS of both lumbar pain and leg pain. The overall fusion rate was 77.7%. Complications were reported in two patients in Group A, one in Group B, and none in Group C. The average operative time showed a trend of gradual decline. The learning curve was characterized using a cubic regression analysis as y = –27.07x + 1.42x2–0.24x3 + 521.84 (R2 = 0.617, p = 0.000).

Conclusions

FE-PLIF is an effective and safe method for treating low back pain caused by short-segmental degenerative diseases. The learning curve of this technique is steep at the initial stage but acceptable and shows great potential for improvement.

Audit on Compliance to Guidelines in CT Scanning for Urolithiasis

Introduction

According to the ALARA principle, CT-imaging procedures should be implemented to optimize radiation doses. The purpose of this study is to determine whether a quality control process has an impact on compliance with procedures.

Materials and methods

This retrospective study was conducted in three hospitals, focusing on the selection of the appropriate acquisition protocol and the reduction of acquisition height in abdominal computed tomography (CT) examinations performed to diagnose or rule out urolithiasis. A first audit was conducted to measure the compliance with the procedure. Next, a reminder of the CT-urolithiasis procedure was given to stakeholders. Three months later, a second audit was conducted to measure the impact of the repeat recall information on compliance, and to compare the outcome with an earlier audit conducted five years earlier.

Results

We included 517 'urolithiasis CT examinations'. The compliance ranged from 41.67% to 64.8% for the first audit. After the reminder of the urolithiasis procedure, compliance ranged from 50% to 76.10%. This improvement was statistically significant for hospital A and B (p < 0.001 for hospital A, p = 0.013 for hospital B) but not for hospital C (p = 0.405). Despite prior demonstration that improved compliance persisted at one year from an initial audit, our actual data show that this compliance had decreased at year five, confirming the need to repeat compliance audits more frequently, or to monitor it continuously.

Conclusion

Surveying compliance to procedures can improve compliance but only for a limited duration. Monitoring compliance more frequently or even continuously is recommended.

Cancer risk following low doses of ionising radiation - Current epidemiological evidence and implications for radiological protection

Recent studies suggest that every year worldwide about a million patients might be exposed to doses of the order of 100 mGy of low-LET radiation, due to recurrent application of radioimaging procedures. This paper presents a synthesis of recent epidemiological evidence on radiation-related cancer risks from low-LET radiation doses of this magnitude. Evidence from pooled analyses and meta-analyses also involving epidemiological studies that, individually, do not find statistically significant radiation-related cancer risks is reviewed, and evidence from additional and more recent epidemiological studies of radiation exposures indicating excess cancer risks is also summarized. Cohorts discussed in the present paper include Japanese atomic bomb survivors, nuclear workers, patients exposed for medical purposes, and populations exposed environmentally to natural background radiation or radioactive contamination. Taken together, the overall evidence summarized here is based on studies including several million individuals, many of them followed-up for more than half a century. In summary, substantial evidence was found from epidemiological studies of exposed groups of humans that ionizing radiation causes cancer at acute and protracted doses above 100 mGy, and growing evidence for doses below 100 mGy. The significant radiation-related solid cancer risks observed at doses of several 100 mGy of protracted exposures (observed, for example, among nuclear workers) demonstrate that doses accumulated over many years at low dose rates do cause stochastic health effects. On this basis, it can be concluded that doses of the order of 100 mGy from recurrent application of medical imaging procedures involving ionizing radiation are of concern, from the viewpoint of radiological protection.

Risk Factors for Childhood Leukemia: Radiation and Beyond

Childhood leukemia (CL) is undoubtedly caused by a multifactorial process with genetic as well as environmental factors playing a role. But in spite of several efforts in a variety of scientific fields, the causes of the disease and the interplay of possible risk factors are still poorly understood. To push forward the research on the causes of CL, the German Federal Office for Radiation Protection has been organizing recurring international workshops since 2008 every two to three years. In November 2019 the 6th International Workshop on the Causes of CL was held in Freising and brought together experts from diverse disciplines. The workshop was divided into two main parts focusing on genetic and environmental risk factors, respectively. Two additional special sessions addressed the influence of natural background radiation on the risk of CL and the progress in the development of mouse models used for experimental studies on acute lymphoblastic leukemia, the most common form of leukemia worldwide. The workshop presentations highlighted the role of infections as environmental risk factor for CL, specifically for acute lymphoblastic leukemia. Major support comes from two mouse models, the Pax5+/- and Sca1-ETV6-RUNX1 mouse model, one of the major achievements made in the last years. Mice of both predisposed models only develop leukemia when exposed to common infections. These results emphasize the impact of gene-environment-interactions on the development of CL and warrant further investigation of such interactions - especially because genetic predisposition is detected with increasing frequency in CL. This article summarizes the workshop presentations and discusses the results in the context of the international literature.

PATIENT-SPECIFIC ORGAN DOSE EVALUATION BASED ON MONTE CARLO SIMULATION AND DOSE METRICS IN PAEDIATRIC CHEST-ABDOMEN-PELVIS CT EXAMINATIONS

This study aimed to determine organ doses based on Monte Carlo (MC) simulations for individual paediatric patients undergoing chest-abdomen-pelvis computed tomography (CT) examinations and to evaluate correlations of organ doses with dose metrics. MC simulations were performed by inputting detailed descriptions of a CT scanner, scanning parameters and CT images of 51 paediatric patients aged from 0 to 10 years into the simulation software. Organ doses for six radiosensitive organs were determined from dose distribution images obtained as the simulation results. The correlations of organ doses with dose metrics such as volume CT dose index, size-specific dose estimates (SSDEs), and organ-specific SSDEs were evaluated from the corresponding coefficients of determination. Organ doses for ages of 0-1 and 1-5 years were 22%-32% lower than those for ages of 5-10 years. Organ doses exhibited higher linear correlations with SSDEs and organ-specific SSDEs, and can be easily estimated using the linear regression.

Radiography and Clinical Decision-Making in Chiropractic

The concern over x-ray exposure risks can overshadow the potential benefit of radiography, especially in cases where manual therapy is employed. Spinal malalignment cannot be accurately visualized without imaging. Manual therapy and the load tolerances of injured spinal tissues raise different criteria for the use of x-rays for spinal disorders than in medical practice. Current regulatory bodies rely on radiography risk assessments based on Linear-No-Threshold (LNT) risk models. There is a need to consider radiography guidelines for chiropractic which are different from those for medical practice. Radiography practice guidelines are summaries dominated by frequentist interpretations in the analysis of data from studies. In contrast, clinicians often employ a pseudo-Bayesian form of reasoning during the clinical decision-making process. The overrepresentation of frequentist perspectives in evidence-based practice guidelines alter decision-making away from practical assessment of a patient's needs, toward an overly cautious standard applied to patients without regard to their risk/benefit likelihoods relating to radiography. Guidelines for radiography in chiropractic to fully assess the condition of the spine and spinal alignment prior to manual therapy, especially with high velocity, low amplitude spinal manipulation (HVLA-SM), should necessarily differ from those used in medical practice.