Association of Exposure to Diagnostic Low-Dose Ionizing Radiation With Risk of Cancer Among Youths in South Korea

Let's talk about radiation dose and radiation protection in children

Children are more sensitive to ionizing radiation than adults. Even though the risk is very low, exposure from radiological examinations can possibly cause them long-term side effects. Recent large epidemiological studies involving children and young adults have added evidence suggesting that even small doses of radiation, such as those from computed tomography scans, might slightly increase the risk of developing cancer later in life. Therefore, even though radiologic studies are essential for an accurate diagnosis and management of various conditions, it is crucial to minimize radiation exposure. This article addresses radiation protection for children in the medical use of ionizing radiation and it is set in the context of the European legislative framework regarding radiation protection. It advocates for a holistic approach to paediatric radiological tests. This approach includes the key principles of radiation protection, such as the justification of imaging procedures supported by referral guidelines, as well as the optimization of techniques (according to the ALARA principle) and effective communication with parents about the benefits and the risks of radiologic procedures. Protecting children from unnecessary radiation is not only a technical challenge, but also a moral obligation and a legal requirement.

Impact and effect of imaging referral guidelines on patients and radiology services: a systematic review

OBJECTIVES

The objective of this systematic review was to offer a comprehensive overview and explore the associated outcomes from imaging referral guidelines on various key stakeholders, such as patients and radiologists.

MATERIALS AND METHODS

An electronic database search was conducted in Medline, Embase and Web of Science to retrieve citations published between 2013 and 2023. The search was constructed using medical subject headings and keywords. Only full-text articles and reviews written in English were included. The quality of the included papers was assessed using the mixed methods appraisal tool. A narrative synthesis was undertaken for the selected articles.

RESULTS

The search yielded 4384 records. Following the abstract, full-text screening, and removal of duplication, 31 studies of varying levels of quality were included in the final analysis. Imaging referral guidelines from the American College of Radiology were most commonly used. Clinical decision support systems were the most evaluated mode of intervention, either integrated or standalone. Interventions showed reduced patient radiation doses and waiting times for imaging. There was a general reduction in radiology workload and utilisation of diagnostic imaging. Low-value imaging utilisation decreased with an increase in the appropriateness of imaging referrals and ratings and cost savings. Clinical effectiveness was maintained during the intervention period without notable adverse consequences.

CONCLUSION

Using evidence-based imaging referral guidelines improves the quality of healthcare and outcomes while reducing healthcare costs. Imaging referral guidelines are one essential component of improving the value of radiology in the healthcare system.

CLINICAL RELEVANCE STATEMENT

There is a need for broader dissemination of imaging referral guidelines to healthcare providers globally in tandem with the harmonisation of the application of these guidelines to improve the overall value of radiology within the healthcare system.

KEY POINTS

The application of imaging referral guidelines has an impact and effect on patients, radiologists, and health policymakers. The adoption of imaging referral guidelines in clinical practice can impact healthcare costs and improve healthcare quality and outcomes. Implementing imaging referral guidelines contributes to the attainment of value-based radiology.

Possible association of G6PC2 and MUC6 induced by low‑dose‑rate irradiation in mouse intestine with inflammatory bowel disease

Although there are several types of radiation exposure, it is debated whether low‑dose‑rate (LDR) irradiation (IR) affects the body. Since the small intestine is a radiation‑sensitive organ, the present study aimed to evaluate how it changes when exposed to LDR IR and identify the genes sensitive to these doses. After undergoing LDR (6.0 mGy/h) γ radiation exposure, intestinal RNA from BALB/c mice was extracted 1 and 24 h later. Mouse whole genome microarrays were used to explore radiation‑induced transcriptional alterations. Reverse transcription‑quantitative (RT‑q) PCR was used to examine time‑ and dose‑dependent radiation responses. The histopathological status of the jejunum in the radiated mouse was not changed by 10 mGy of LDR IR; however, 23 genes were upregulated in response to LDR IR of the jejunum in mice after 1 and 24 h of exposure. Upregulated genes were selected to validate the results of the RNA sequencing analysis for RT‑qPCR detection and results showed that only Na+/K+ transporting subunit α4, glucose‑6‑phosphatase catalytic subunit 2 (G6PC2), mucin 6 (MUC6) and transient receptor potential cation channel subfamily V member 6 levels significantly increased after 24 h of LDR IR. Furthermore, G6PC2 and MUC6 were notable genes induced by LDR IR exposure according to protein expression via western blot analysis. The mRNA levels of G6PC2 and MUC6 were significantly elevated within 24 h under three conditions: i) Exposure to LDR IR, ii) repeated exposure to LDR IR and iii) exposure to LDR IR in the presence of inflammatory bowel disease. These results could contribute to an improved understanding of immediate radiation reactions and biomarker development to identify radiation‑susceptible individuals before histopathological changes become noticeable. However, further investigation into the specific mechanisms involving G6PC2 and MUC6 is required to accomplish this.

Risk of Lymphoma and Leukemia in Thyroid Cancer Patients: A Retrospective Cohort Study in Germany

Thyroid cancer is the ninth most common cancer worldwide. While differentiated thyroid cancer (DTC) has a high survival rate, concerns arise regarding optimal treatment strategies and potential long-term risks, including second primary malignancies (SPMs), associated with therapies such as radioiodine (RAI). The aim of the present study was to investigate the association between thyroid cancer and the incidence of subsequent lymphoma and leukemia in Germany. This retrospective cohort study used the IQVIA TM Disease Analyzer database and included adults with a first documented diagnosis of thyroid cancer between January 2005 and December 2021 as well as propensity score matched individuals without thyroid cancer in 1284 general practices. Univariate Cox regression models were performed to examine the association between thyroid cancer and the incidence of subsequent lymphoma and leukemia. A total of 4232 thyroid cancer patients (mean age: 54.2 years; 73.6% female) and 21 160 controls (mean age: 54.2 years; 72.6% female) were available for analyses. Thyroid cancer was significantly associated with a higher lymphoma incidence (HR: 3.35, 95% CI: 2.04-5.52), especially in men (HR: 5.37) and those aged 61-70 years. Leukemia incidence was not significantly associated with thyroid cancer (HR: 1.79, 95% CI: 0.91-3.53), although associations were notable in younger age groups. Thyroid cancer is positively associated with a risk of subsequent lymphoma, highlighting the need for vigilant surveillance and tailored treatment strategies. While the association with leukemia is less pronounced, close surveillance remains critical, especially in younger patients.

CT informs detection and treatment options in rheumatoid arthritis complicated by pulmonary non-tuberculous mycobacterial disease from the FIRST registry

OBJECTIVE

To investigate the early detection of pulmonary non-tuberculous mycobacterial (PNTM) disease by CT before the initiation of molecular-targeted therapeutic drugs in patients with rheumatoid arthritis (RA) and the efficacy and safety of combined treatment with antibiotics.

METHODS

Patients with RA underwent chest CT before the introduction of molecular-targeted therapies in the Further Improvement of Rheumatoid arthritis Treatment registry. The primary endpoint was the number of patients who were detected by CT as having PNTM disease, complicating RA.

RESULTS

Of 4447 patients with RA who underwent chest CT, 107 had suspected PNTM disease, and 33 diagnoses were confirmed by culture. In 14 of the 33 patients, plain radiographs showed no abnormalities; PNTM disease was only observed on CT scans. The prevalence of PNTM disease in patients with RA requiring molecular-targeted treatment was six times higher than that in healthy individuals. 31 patients initiated molecular-targeted therapeutic drugs in combination with anti-NTM treatment, and 28 were followed up for 24 months. No significant difference was observed in the retention rate and RA disease activity at 24 months between the PNTM and non-PNTM groups. Coexisting PNTM disease did not affect treatment discontinuation. None of the 28 patients in the PNTM group experienced exacerbation of PNTM disease.

CONCLUSION

CT screening before the initiation of molecular-targeted treatment enabled the detection of asymptomatic PNTM that was undetectable on plain radiographs. This study showed that molecular-targeted therapeutic drugs in combination with anti-NTM treatment could control the disease activity of both PNTM and RA.

Establishment of National Diagnostic Reference Levels for Administered Activity in Diagnostic Nuclear Medicine in Thailand

The diagnostic reference level (DRL) is a patient-exposure optimization tool used to evaluate radiation doses in medical imaging and provide guidance for protection from them. In Thailand, nuclear medicine DRLs have not been established yet. Therefore, this study surveyed dose levels in routine nuclear medicine procedures to provide national DRLs (NDRLs). Methods: NDRLs in Thailand were established by investigating the administered activity of radiopharmaceuticals in nuclear medicine examination studies. The NDRLs were determined on the basis of the 75th percentile (third quartile) of administered activity distribution as recommended by the International Commission on Radiological Protection. As part of a nationwide survey, datasets for the period between June 1, 2018, and August 31, 2019, were collected from 21 Thailand hospitals with nuclear medicine equipment. All hospitals were asked to report the nuclear medicine imaging devices in use, the standard protocol parameters for selected examinations, the injected activities, and the ages and weights of patients. All data were calculated to determine Thailand NDRLs, which were compared with international NDRLs. Results: The data reported by the 21 hospitals consisted of 4,641 examinations with SPECT or SPECT/CT for general nuclear medicine and 409 examinations with PET. The most widely performed examinations for SPECT were bone, thyroid, oncology, and cardiovascular imaging. The NDRLs for SPECT or SPECT/CT agreed well with published NDRLs for Europe, the United States, Japan, Korea, Kuwait, and Australia. In contrast, the NDRLs for 18F-FDG PET in oncology studies were higher than for Japan, Korea, Kuwait, and Australia but lower than for the United States, the United Kingdom, and the European Union. Conclusion: This study presents NDRL results for adults in Thailand as a way to optimize radiation protection in nuclear medicine imaging. Moreover, the reported injected activity levels were comparable to those of other countries.

Risk of hematologic malignant neoplasms from head CT radiation in children and adolescents presenting with minor head trauma: a nationwide population-based cohort study

OBJECTIVES

The carcinogenic risks of CT radiation in children and adolescents remain debated. We aimed to assess the carcinogenic risk of CTs performed in children and adolescents with minor head trauma.

METHODS

In this nationwide population-based cohort study, we included 2,411,715 patients of age 0-19 with minor head trauma from 2009 to 2017. We excluded patients with elevated cancer risks or substantial past medical radiation exposure. Patients were categorized into CT-exposed or CT-unexposed group according to claim codes for head CT. The primary outcome was development of hematologic malignant neoplasms. Secondary outcomes included development of malignant solid neoplasms and benign neoplasms in the brain. We measured the incidence rate ratio (IRR) and incidence rate difference (IRD) using G-computation with Poisson regression adjusting for age, sex, hospital setting, and the type of head trauma.

RESULTS

Hematologic malignant neoplasms developed in 100 of 216,826 patients during 1,303,680 person-years in the CT-exposed group and in 808 of 2,194,889 patients during 13,501,227 person-years in the CT-unexposed group. For hematologic malignant neoplasms, the IRR was 1.29 (95% CI, 1.03-1.60) and the IRD was 1.71 (95% CI, 0.04-3.37) per 100,000 person-years at risk. The majority of excess hematologic malignant neoplasms were leukemia (IRR, 1.40 [98.3% CI, 1.05-1.87]; IRD, 1.59 [98.3% CI, 0.02-3.16] per 100,000 person-years at risk). There were no between-group differences for secondary outcomes.

CONCLUSIONS

Radiation exposure from head CTs in children and adolescents with minor head trauma was associated with an increased incidence of hematologic malignant neoplasms.

CLINICAL RELEVANCE STATEMENT

Our study provides a quantitative grasp of the risk conferred by CT examinations in children and adolescents, thereby providing the basis for cost-benefit analyses and evidence-driven guidelines for patient triaging in head trauma.

KEY POINTS

• This nationwide population-based cohort study showed that radiation exposure from head CTs in children and adolescents was associated with a higher incidence of hematologic malignant neoplasms. • The incidence rate of hematologic malignant neoplasms in the CT-exposed group was 29% higher than that in the CT-unexposed group (IRR, 1.29 [95% CI, 1.03-1.60]), and there were approximately 1.7 excess neoplasms per 100,000 person-years at risk in the CT-exposed group (IRD, 1.71 [0.04-3.37]). • Our study provides a quantified grasp of the risk conferred by CT examinations in children and adolescents, while controlling for biases observed in previous studies via specifying CT indication and excluding patients with predisposing conditions for cancer development.

Radiation reduction for interventional radiology imaging: a video frame interpolation solution

PURPOSE

The aim of this study was to diminish radiation exposure in interventional radiology (IR) imaging while maintaining image quality. This was achieved by decreasing the acquisition frame rate and employing a deep neural network to interpolate the reduced frames.

METHODS

This retrospective study involved the analysis of 1634 IR sequences from 167 pediatric patients (March 2014 to January 2022). The dataset underwent a random split into training and validation subsets (at a 9:1 ratio) for model training and evaluation. Our approach proficiently synthesized absent frames in simulated low-frame-rate sequences by excluding intermediate frames from the validation subset. Accuracy assessments encompassed both objective experiments and subjective evaluations conducted by nine radiologists.

RESULTS

The deep learning model adeptly interpolated the eliminated frames within IR sequences, demonstrating encouraging peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM) results. The average PSNR values for angiographic, subtraction, and fluoroscopic modes were 44.94 dB, 34.84 dB, and 33.82 dB, respectively, while the corresponding SSIM values were 0.9840, 0.9194, and 0.7752. Subjective experiments conducted with experienced interventional radiologists revealed minimal discernible differences between interpolated and authentic sequences.

CONCLUSION

Our method, which interpolates low-frame-rate IR sequences, has shown the capability to produce high-quality IR images. Additionally, the model exhibits potential for reducing the frame rate during IR image acquisition, consequently mitigating radiation exposure.

CRITICAL RELEVANCE STATEMENT

This study presents a critical advancement in clinical radiology by demonstrating the effectiveness of a deep neural network in reducing radiation exposure during pediatric interventional radiology while maintaining image quality, offering a potential solution to enhance patient safety.

KEY POINTS

• Reducing radiation: cutting IR image to reduce radiation. • Accurate frame interpolation: our model effectively interpolates missing frames. • High visual quality in terms of PSNR and SSIM, making IR procedures safer without sacrificing quality.

Risk factors for childhood brain tumours: A systematic review and meta-analysis of observational studies from 1976 to 2022

BACKGROUND

Childhood brain tumours (CBTs) are the leading cause of cancer death in children under the age of 20 years globally. Though the aetiology of CBT remains poorly understood, it is thought to be multifactorial. We aimed to synthesize potential risk factors for CBT to inform primary prevention.

METHODS

We conducted a systematic review and meta-analysis of epidemiological studies indexed in the PubMed, Web of Science, and Embase databases from the start of those resources through 27 July 2023. We included data from case-control or cohort studies that reported effect estimates for each risk factor around the time of conception, during pregnancy and/or during post-natal period. Random effects meta-analysis was used to estimate summary effect sizes (ES) and 95% confidence intervals (CIs). We also quantified heterogeneity (I2) across studies.

FINDINGS

A total of 4040 studies were identified, of which 181 studies (85 case-control and 96 cohort studies) met our criteria for inclusion. Of all eligible studies, 50% (n = 91) were conducted in Europe, 32% (n = 57) in North America, 9% (n = 16) in Australia, 8% (n = 15) in Asia, 1% (n = 2) in South America, and none in Africa. We found associations for some modifiable risk factors including childhood domestic exposures to insecticides (ES 1.44, 95% CI 1.20-1.73) and herbicides (ES 2.38, 95% CI 1.31-4.33). Maternal domestic exposure to insecticides (ES 1.45, 95% CI 1.09-1.94), maternal consumption of cured meat (ES 1.51, 95% CI 1.05-2.17) and coffee ≥ 2 cups/day (ES 1.45, 95% 95% CI 1.07-1.95) during pregnancy, and maternal exposure to benzene (ES 2.22; 95% CI 1.01-4.88) before conception were associated with CBTs in case-control studies. Also, paternal occupational exposure to pesticides (ES 1.48, 95% CI 1.23-1.77) and benzene (ES 1.74, 95% CI 1.10-2.76) before conception and during pregnancy were associated in case-control studies and in combined analysis. On the other hand, assisted reproductive technology (ART) (ES 1.32, 95% CI 1.05-1.67), caesarean section (CS) (ES 1.12, 95% CI 1.01-1.25), paternal occupational exposure to paint before conception (ES 1.56, 95% CI 1.02-2.40) and maternal smoking > 10 cigarettes per day during pregnancy (ES 1.18, 95% CI 1.00-1.40) were associated with CBT in cohort studies. Maternal intake of vitamins and folic acid during pregnancy was inversely associated in cohort studies. Hormonal/infertility treatment, breastfeeding, child day-care attendance, maternal exposure to electric heated waterbed, tea and alcohol consumption during pregnancy were among those not associated with CBT in both case-control and cohort studies.

CONCLUSION

Our results should be interpreted with caution, especially as most associations between risk factors and CBT were discordant between cohort and case-control studies. At present, it is premature for any CBT to define specific primary prevention guidelines.

A survey of non-sedate practices when acquiring pediatric magnetic resonance imaging examinations

BACKGROUND

Improving access to magnetic resonance imaging (MRI) in childhood can be facilitated by making it faster and cheaper and reducing need for sedation or general anesthesia (GA) to mitigate motion. Some children achieve diagnostic quality MRI without GA through the use of non- practices fostering their cooperation and/or alleviating anxiety. Employed before and during MRI, these variably educate, distract, and/or desensitize patients to this environment.

OBJECTIVE

To assess current utilization of non-sedate practices in pediatric MRI, including variations in practice and outcomes.

MATERIALS AND METHODS

A survey-based study was conducted with 1372 surveys emailed to the Society for Pediatric Radiology members in February 2021, inviting one response per institution.

RESULTS

Responses from 50 unique institutions in nine countries revealed 49/50 (98%) sites used ≥ 1 non-sedate practice, 48/50 (96%) sites in infants < 6 months, and 11/50 (22%) for children aged 6 months to 3 years. Non-sedate practices per site averaged 4.5 (range 0-10), feed and swaddle used at 47/49 (96%) sites, and child life specialists at 35/49 (71%). Average success rates were moderate (> 50-75%) across all sites and high (> 75-100%) for 20% of sites, varying with specific techniques. Commonest barriers to use were scheduling conflicts and limited knowledge.

CONCLUSION

Non-sedate practice utilization in pediatric MRI was near-universal but widely variable across sites, ages, and locales, with room for broader adoption. Although on average non-sedate practice success rates were similar, the range in use and outcomes suggest a need for standardized implementation guidelines, including patient selection and outcome metrics, to optimize utilization and inform educational initiatives.

Radiation-Related Thyroid Cancer

Radiation is an environmental factor that elevates the risk of developing thyroid cancer. Actual and possible scenarios of exposures to external and internal radiation are multiple and diverse. This article reviews radiation doses to the thyroid and corresponding cancer risks due to planned, existing, and emergency exposure situations, and medical, public, and occupational categories of exposures. Any exposure scenario may deliver a range of doses to the thyroid, and the risk for cancer is addressed along with modifying factors. The consequences of the Chornobyl and Fukushima nuclear power plant accidents are described, summarizing the information on thyroid cancer epidemiology, treatment, and prognosis, clinicopathological characteristics, and genetic alterations. The Chornobyl thyroid cancers have evolved in time: becoming less aggressive and driver shifting from fusions to point mutations. A comparison of thyroid cancers from the 2 areas reveals numerous differences that cumulatively suggest the low probability of the radiogenic nature of thyroid cancers in Fukushima. In view of continuing usage of different sources of radiation in various settings, the possible ways of reducing thyroid cancer risk from exposures are considered. For external exposures, reasonable measures are generally in line with the As Low As Reasonably Achievable principle, while for internal irradiation from radioactive iodine, thyroid blocking with stable iodine may be recommended in addition to other measures in case of anticipated exposures from a nuclear reactor accident. Finally, the perspectives of studies of radiation effects on the thyroid are discussed from the epidemiological, basic science, and clinical points of view.

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.

Establishing Protocol-based Dose Metrics for Common Abdomen and Pelvis Computed Tomography Protocols

BACKGROUND AND AIM

The majority of the existing diagnostic reference levels (DRLs) that have been established for computed tomography (CT) are based on various anatomical locations, such as the head, chest, abdomen, etc. However, DRLs are initiated to improve radiation protection by conducting a comparison of similar examinations with similar objectives. The aim of this study was to explore the feasibility of establishing dose baselines based on common CT protocols for patients who underwent enhanced CT abdomen and pelvis exams.

METHODS

Dose length product total (tDLPs), volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), effective dose (E), and scan acquisition parameters for a total of 216 adult patients, who underwent an enhanced CT abdomen and pelvis exams over a one-year period, were obtained and retrospectively analyzed. Spearman coefficient and one-way ANOVA tests were used to check significant differences between dose metrics and the different CT protocols.

RESULTS

The data exhibited 9 different CT protocols to acquire an enhanced CT abdomen and pelvis exam at our institute. Out of these, 4 were found more common, i.e., CT protocols were acquired for a minimum of 10 cases. Triphasic liver demonstrated the highest mean and median tDLPs across all 4 CT protocols. Triphasic liver protocol registered the highest E followed by gastric sleeve protocol with a mean of 28.7 and 24.7 mSv, respectively. Significant differences (p < 0.0001) were found between the tDLPs of anatomical location and the CT protocol.

CONCLUSION

Evidently, wide variability exists across CT dose indices and patient dose metrics relying on anatomical-based dose baseline, i.e., DRLs. Patient dose optimizations require establishing dose baselines based on CT protocols rather than the anatomical location.

Color Doppler ultrasound versus CT angiography for DIEP flap planning: A randomized controlled trial

BACKGROUND

Identifying relevant perforators is crucial in planning a deep inferior epigastric perforator (DIEP) flap. Color Doppler ultrasonography (CDU) has gained popularity for localizing perforators; however, current evidence on its efficiency is still inconclusive. This study aimed to compare the efficiency of CDU with that of computed tomography angiography (CTA) in localizing and selecting the relevant perforators.

METHODS

In this randomized controlled trial, 60 patients undergoing DIEP flap breast reconstruction (uni- or bilateral) were randomly assigned to the CDU group (i.e., CDU was performed to map and select the relevant perforators preoperatively) or the CTA+CDU group (i.e., mapping was based on CTA and supplemented by CDU). CDU was performed by the same surgeon with a well-defined sonography experience from our previous study. The reference XY coordinates of the dissected perforators were measured intraoperatively, and deviations from preoperatively deducted coordinates were calculated (ΔCDU or ΔCTA+CDU). The flaps were categorized according to the number of dissected perforators, and adherence to the preoperative strategy was evaluated.

RESULTS

Overall, 22 patients (30 flaps) in the CTA+CDU group and 27 (39 flaps) patients in the CDU group were evaluated. The average ΔCDU (0.6 cm) was significantly lower than the average ΔCTA+CDU (1.0 cm) (p < 0.001). Adherence to the mapping-based dissection strategy was higher in the CDU group; however, the difference was insignificant (p = 0.092).

CONCLUSION

CDU is not inferior to CTA + CDU in localizing and selecting relevant DIEA perforators. Therefore, CDU mapping is a possible complementary or substitute modality for CTA mapping.

Computed tomography for malignancy screening in patients with rheumatoid arthritis before initiation of disease modifying antirheumatic drug

OBJECTIVES

This study aimed to clarify the usefulness of screening for malignancies using CT before the initiation of biologic and targeted synthetic DMARDs (b/tsDMARDs) in patients with active RA.

METHODS

We examined 2192 patients with RA who underwent plain CT scans prior to the initiation of b/tsDMARDs. The sensitivity for detecting malignancy was measured and compared with that of regular screening (physical examination and X-ray). We then evaluated the clinical characteristics, prognosis and treatment of patients with RA with concomitant malignancies. Additionally, we determined the incidence rate of malignancy in patients with RA who were initiated on b/tsDMARDs after CT screening.

RESULTS

Of the 2192 patients, 33 (1.5%) were diagnosed with malignancy after CT screening. Whereas regular screening detected only seven malignancies, CT screening further detected 26 (including 19 at the early stage). On the other hand, 86% of the malignancies detectable by regular screening were at an advanced stage. Patients diagnosed with early-stage malignancies received RA treatments that included b/tsDMARDs after curative resection; 80% of these patients achieved low disease activity after 1 year. This rate was comparable to the patients without malignancy detection after screening (70%). The 5 year incidence of malignancy after the initiation of b/tsDMARDs after CT screening was lower than that of the RA cohort without CT screening (standardized incidence ratio: 0.35).

CONCLUSION

Screening in patients with RA using CT before the initiation of b/tsDMARDs allows for the early detection and treatment of malignancy, resulting in safer and more stable b/tsDMARD treatments.

Computed tomography scan radiation and brain cancer incidence

BACKGROUND

Computed tomography (CT) scans make substantial contributions to low-dose ionizing radiation exposures, raising concerns about excess cancers caused by diagnostic radiation.

METHODS

Deidentified medicare records for all Australians aged 0-19 years between 1985-2005 were linked to national death and cancer registrations to 2012. The National Cancer Institute CT program was used to estimate radiation doses to the brain from CT exposures in 1985-2005, Poisson regression was used to model the dependence of brain cancer incidence on brain radiation dose, which lagged by 2 years to minimize reverse causation bias.

RESULTS

Of 10 524 842 young Australians, 611 544 were CT-exposed before the age of 20 years, with a mean cumulative brain dose of 44 milligrays (mGy) at an average follow-up of 13.5 years after the 2-year lag period. 4472 were diagnosed with brain cancer, of whom only 237 had been CT-exposed. Brain cancer incidence increased with radiation dose to the brain, with an excess relative risk of 0.8 (95% CI 0.57-1.06) per 100 mGy. Approximately 6391 (95% CI 5255, 8155) persons would need to be exposed to cause 1 extra brain cancer.

CONCLUSIONS

For brain tumors that follow CT exposures in childhood by more than 2 years, we estimate that 40% (95% CI 29%-50%) are attributable to CT Radiation and not due to reverse causation. However, because of relatively low rates of CT exposure in Australia, only 3.7% (95% CI 2.3%-5.4%) of all brain cancers are attributable to CT scans. The population-attributable fraction will be greater in countries with higher rates of pediatric scanning.

The Future of Radioactive Medicine

The discovery of X rays in the late 19th century heralded the beginning of a new age in medicine, and the advent of channeling the power of radiation to diagnose and treat human disease. Radiation has been leveraged in medicine in a multitude of ways and is a critical element of cancer care including screening, diagnosis, surveillance, and interventional treatments. Modern radiotherapy techniques include a multitude of methodologies utilizing both externally and internally delivered radiation from a variety of approaches. This review provides a comprehensive overview of contemporary radiotherapy methodologies, the field of radiopharmaceuticals and theranostics, effects of low dose radiation and highlights the phenomena of fear of exposure to radiation and its impact in modern medicine.

Increasing Cancer in Adolescents and Young Adults: Cancer Types and Causation Implications

Purpose: This study aimed to identify cancer incidence trends in the United States and globally in adolescents and young adults (AYAs) 15-39 years of age, by sex, and to speculate on causes for trend changes. Methods: For the United States, SEER*Stat was used to obtain average annual percent change (AAPC) trends in cancer incidence during the period 2000-2019 among 395,163 AYAs. For global data, the source was the Institute of Health Metrics and Evaluation and its sociodemographic index (SDI) classification system. Results: In the United States, the invasive cancer incidence increased during the period 2000-2019 in both females (AAPC: 1.05, 95% CI: 0.90-1.20, p << 0.001) and males (AAPC: 0.56, 95% CI: 0.43-0.69, p << 0.001). A total of 25 and 20 types of cancers increased statistically significantly in female and male AYAs, respectively. Among potential causes for the increases, the obesity epidemic in the United States strongly correlates with the overall cancer increase in both its female (Pearson correlation coefficient R2 = 0.88, p = 0.0007) and male (R2 = 0.83, p = 0.003) AYAs, as does the most common malignancy in American AYAs, breast cancer (R2 = 0.83, p = 0.003). Worldwide, cancer incidence in the age group increased steadily during the period 2000-2019 among high-middle, middle, and low-middle SDI countries, but not in low SDI countries and with slowing of increase in high SDI countries. Conclusions: The increases and their age-dependent profiles implicate several causations that are preventable, including obesity, overdiagnosis, unnecessary diagnostic radiation, human papilloma virus infection, and cannabis avoidance. The United States is beginning to reverse the increasing incidence, and prevention efforts should be augmented accordingly.

Real-time continuous image guidance for endoscopic retrograde cholangiopancreatography based on 3D/2D registration and respiratory compensation

BACKGROUND

It has been confirmed that three-dimensional (3D) imaging allows easier identification of bile duct anatomy and intraoperative guidance of endoscopic retrograde cholangiopancreatography (ERCP), which reduces the radiation dose and procedure time with improved safety. However, current 3D biliary imaging does not have good real-time fusion with intraoperative imaging, a process meant to overcome the influence of intraoperative respiratory motion and guide navigation. The present study explored the feasibility of real-time continuous image-guided ERCP.

AIM

To explore the feasibility of real-time continuous image-guided ERCP.

METHODS

We selected 2 3D-printed abdominal biliary tract models with different structures to simulate different patients. The ERCP environment was simulated for the biliary phantom experiment to create a navigation system, which was further tested in patients. In addition, based on the estimation of the patient's respiratory motion, preoperative 3D biliary imaging from computed tomography of 18 patients with cholelithiasis was registered and fused in real-time with 2D fluoroscopic sequence generated by the C-arm unit during ERCP.

RESULTS

Continuous image-guided ERCP was applied in the biliary phantom with a registration error of 0.46 mm ± 0.13 mm and a tracking error of 0.64 mm ± 0.24 mm. After estimating the respiratory motion, 3D/2D registration accurately transformed preoperative 3D biliary images to each image in the X-ray image sequence in real-time in 18 patients, with an average fusion rate of 88%.

CONCLUSION

Continuous image-guided ERCP may be an effective approach to assist the operator and reduce the use of X-ray and contrast agents.

Quantitative Analysis of the Clinical Reasons Influencing the Frequency of Pediatric Head CT Examinations: A Single-Center Observation Study

Epidemiological studies on radiation exposure from pediatric CT scans have attracted attention in terms of radiological protection. These studies have not taken into account the reasons why CT examinations were performed. It is presumed that there are clinical reasons that justify more frequent CT examinations in children. The purpose of this study was to characterize the clinical reasons why relatively high numbers of head CT examinations (NHCT) are frequently performed and to conduct a statistical analysis to determine the factors governing the NHCT. Patient information, the date of examination, and medical conditions for examination data stored on the radiology information system were used to investigate the reasons for undergoing CT examinations. The target facility was National Children's Hospital; data were obtained from March 2002 to April 2017, and the age of the study population was less than 16 years old. Quantitative analysis of the factors associated with frequent examinations was conducted by Poisson regression analysis. Among all patients who had a CT scan, 76.6% had head CT examinations, and 43.4% of children were under 1 year old at the time of the initial examination. There were marked differences in the number of examinations depending on the disease. The average NHCT was higher for children younger than 5 days of age. Among children less than 1 year of age with surgery, there was a marked difference between hydrocephalus, with a mean = 15.5 (95% CI 14.3,16.8), and trauma, with a mean = 8.3 (95% CI 7.2,9.4). In conclusion, this study revealed that NHCT was significantly higher in children who had undergone surgery than in those who had not been to the hospital. The clinical reasons behind patients with higher NHCT should be considered in investigating a causal relationship between CT exposure and brain tumors.

Relative biological effectiveness of low-energy X-rays (25 kV) in mutant p53 cancer cells

Low-energy X-rays as used in radiation therapy and diagnostics such as mammography are associated with a certain risk of promoting tumour development, especially in patients with mutations in cancer-related genes like TP53. The present study therefore addressed the relative biological effectiveness (RBE) of low-energy X-rays for two human adenocarcinoma cell lines of the breast (MDA-MB-468) and pancreas (BxPC-3) with a mutation in the TP53 gene. Clonogenic survival and cytogenetic changes in terms of micronuclei (MN) formation were determined following irradiation with 25 kV X-rays and 200 kV reference irradiation in the dose range of 1-8 Gy. Except the frequency of MN-containing binucleated cells (BNC) (BNC + MN/BNC) in breast cancer cells yielding an RBE between 0.6 and 0.8, both cell lines displayed dose-dependent variations of RBE values between 1 and 2 for all biological end points (cell survival, (BNC + MN/BNC), MN/BNC, MN/(BNC + MN)) with increased effectiveness of 25 kV irradiation in pancreatic compared to breast cancer cells. The results confirm previous findings indicating increased effectiveness of low-energy X-rays and underline the necessity of careful risk estimation for cancer screening programmes.

The value of using a deep learning image reconstruction algorithm of thinner slice thickness to balance the image noise and spatial resolution in low-dose abdominal CT

Background

Traditional reconstruction techniques have certain limitations in balancing image quality and reducing radiation dose. The deep learning image reconstruction (DLIR) algorithm opens the door to a new era of medical image reconstruction. The purpose of the study was to evaluate the DLIR images at 1.25 mm thickness in balancing image noise and spatial resolution in low-dose abdominal computed tomography (CT) in comparison with the conventional adaptive statistical iterative reconstruction-V at 40% strength (ASIR-V40%) at 5 and 1.25 mm.

Methods

This retrospective study included 89 patients who underwent low-dose abdominal CT. Five sets of images were generated using ASIR-V40% at a 5 mm slice thickness and 1.25 mm (high-resolution) with DLIR at 1.25 mm using 3 strengths: low (DLIR-L), medium (DLIR-M), and high (DLIR-H). Qualitative evaluation was performed for image noise, artifacts, and visualization of small structures, while quantitative evaluation was performed for standard deviation (SD), signal-to-noise ratio (SNR), and spatial resolution (defined as the edge rising slope).

Results

At 1.25 mm, DLIR-M and DLIR-H images had significantly lower noise (SD in fat: 14.29±3.37 and 9.65±3.44 HU, respectively), higher SNR for liver (3.70±0.78 and 5.64±1.20, respectively), and higher overall image quality (4.30±0.44 and 4.67±0.40, respectively) than did the respective values in ASIR-V40% images (20.60±4.04 HU, 2.60±0.63, and 3.77±0.43; all P values <0.05). Compared with the 5 mm ASIR-V40% images, the 1.25 mm DLIR-H images had lower noise (SD: 9.65±3.44 vs. 13.63±10.03 HU), higher SNR (5.64±1.20 vs. 4.69±1.28), and higher overall image quality scores (4.67±0.40 vs. 3.94±0.46) (all P values <0.001). In addition, DLIR-L, DLIR-M, and DLIR-H images had a significantly higher spatial resolution in terms of edge rising slope (59.66±21.46, 58.52±17.48, and 59.26±13.33, respectively, vs. 33.79±9.23) and significantly higher image quality scores in the visualization of fine structures (4.43±0.50, 4.41±0.49, and 4.38±0.49, respectively vs. 2.62±0.49) than did the 5 mm ASIR-V40 images.

Conclusions

The 1.25 mm DLIR-M and DLIR-H images had significantly reduced image noise and improved SNR and overall image quality compared to the 1.25 mm ASIR-V40% images, and they had significantly improved the spatial resolution and visualization of fine structures compared to the 5 mm ASIR-V40% images. DLIR-H images had further reduced image noise compared with the 5 mm ASIR-V40% images, and DLIR-H was the most effective technique at balancing the image noise and spatial resolution in low-dose abdominal CT.

Pediatric Brain Tumor Risk Associated with Head Computed Tomography: Systematic Literature Review

Computed tomography (CT) of the brain has changed diagnostic neuroradiology significantly over the past 50 years since it was firstly used back in 1971 to visualize suspected frontal lobe tumour. The safety of head CT is determined by the small amount of radiation and the low sensibility of brain tissue to cytotoxic damage due to ionizing radiation compared to other organs. However, some population groups may be at increased risk. Thus, children are more susceptible to radiation cancer than adults and lifelong attributive risk (LAR) can be more than 10 times higher for an infant than for a middle-aged adult. The authors have reviewed published studies that examined the prevalence and mortality of intracranial tumors in children undergoing head CT in comparison to unaffected individuals. Electronic search of publications in the PubMed database from 1966 to date was carried out. We have carried out intersectoral search for documents containing keywords or medical subject headings (MeSH) related to three wide categories: 1) computed tomography, 2) radiation-induced tumors, 3) risk, morbidity or epidemiology. Further search was performed in manual mode. Available epidemiological data generally confirmed correlation between head CT and tumor growth induction. Thus, current epidemiological data accept the opinion that the risk of tumor induction associated with head CT in children is very small (one tumor per 3,000–10,000 studies). The minimal estimated risk of tumor induction due to head CT in children is mostly offset by its diagnostic imaging benefits considering the clinical indications to minimize radiation dose. Understanding and quantitative risk assessment of carcinogenesis associated with CT imaging led to dose reduction in pediatric CT protocols. This trend should continue and should be implemented in all age groups. Although the decision to perform head CT is often undeniable (injury or hemorrhage), careful assessment of studies frequency is required, especially in patients who need disease monitoring. Cumulative effect in such cases may increase the minimal risk of carcinogenesis. Larger and advanced epidemiological studies are required to better understand these risks.

Ultra-low-dose hepatic multiphase CT using deep learning-based image reconstruction algorithm focused on arterial phase in chronic liver disease: A non-inferiority study

PURPOSE

This study determined whether image quality and detectability of ultralow-dose hepatic multiphase CT (ULDCT, 33.3% dose) using a vendor-agnostic deep learning model(DLM) are noninferior to those of standard-dose CT (SDCT, 100% dose) using model-based iterative reconstruction(MBIR) in patients with chronic liver disease focusing on arterial phase.

METHODS

Sixty-seven patients underwent hepatic multiphase CT using a dual-source scanner to obtain two different radiation dose CT scans (100%, SDCT and 33.3%, ULDCT). ULDCT using DLM and SDCT using MBIR were compared. A margin of -0.5 for the difference between the two protocols was pre-defined as noninferiority of the overall image quality of the arterial phase image. Quantitative image analysis (signal to noise ratio[SNR] and contrast to noise ratio[CNR]) was also conducted. The detectability of hepatic arterial focal lesions was compared using the Jackknife free-response receiver operating characteristic analysis. Non-inferiority was satisfied if the margin of the lower limit of 95%CI of the difference in figure-of-merit was less than -0.1.

RESULTS

Mean overall arterial phase image quality scores with ULDCT using DLM and SDCT using MBIR were 4.35 ± 0.57 and 4.08 ± 0.58, showing noninferiority (difference: -0.269; 95 %CI, -0.374 to -0.164). ULDCT using DLM showed a significantly superior contrast-to-noise ratio of arterial enhancing lesion (p < 0.05). Figure-of-merit for detectability of arterial hepatic focal lesion was 0.986 for ULDCT using DLM and 0.963 for SDCT using MBIR, showing noninferiority (difference: -0.023, 95 %CI: -0.016 to 0.063).

CONCLUSION

ULDCT using DLM with 66.7% dose reduction showed non-inferior overall image quality and detectability of arterial focal hepatic lesion compared to SDCT using MBIR.

Lymphatic Intervention, the Frontline of Modern Lymphatic Medicine: Part I. History, Anatomy, Physiology, and Diagnostic Imaging of the Lymphatic System

Recent advances in lymphatic imaging have provided novel insights into the lymphatic system. Interventional radiology has played a significant role in the development of lymphatic imaging techniques and modalities. Radiologists should be familiar with the basic physiology and anatomy of the lymphatic system to understand the imaging features of lymphatic disorders, which reflect their pathophysiology. This study comprehensively reviews the physiological and anatomical aspects of the human lymphatic system as well as the latest lymphatic imaging techniques.

Paediatric kidney stone surgery: state-of-the-art review

While urolithiasis in children is rare, the global incidence is rising, and the volume of minimally invasive surgeries being performed reflects this. There have been many developments in the technology, which have supported the advancement of these interventions. However, innovation of this kind has also resulted in wide-ranging practice patterns and debate regarding how they should be best implemented. This is in addition to the extra challenges faced when treating stone disease in children where the patient population often has a higher number of comorbidities and for example, the need to avoid risk such as ionising exposure is higher. The overall result is a number of challenges and controversies surrounding many facets of paediatric stone surgery such as imaging choice, follow-up and different treatment options, for example, medical expulsive therapy, shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. This article provides an overview of the current status of paediatric stone surgery and discussion on the key topics of debate.

Surgeon-conducted color Doppler ultrasound deep inferior epigastric artery perforator mapping: A cohort study and learning curve assessment

BACKGROUND

Perforator mapping using diagnostic methods facilitates deep inferior epigastric perforator (DIEP) flap planning. Computed tomographic angiography (CTA) is a well-proven tool for perforator mapping. However, the benefits of color Doppler ultrasonography (CDU) are as follows: 1) CDU involves dynamic real-time examination and 2) does not use radiation. Comparing the accuracies of both methods in a cohort of patients, this study aimed to evaluate the learning curve of surgeon-conducted CDU perforator mapping.

METHODS

Twenty patients undergoing DIEP flap breast reconstruction were enrolled in a cohort study. All patients underwent CTA perforator mapping preoperatively. XY coordinates of significant perforators were subtracted by a radiologist. A single surgeon (sonographer) with minimal experience with CDU performed CDU perforator mapping, including XY coordinates subtraction. The sonographer was blinded to the CTA data. The reference coordinates of dissected perforators were measured during surgery. Deviations from reference coordinates for both methods were compared, and CDU mapping learning curve was assessed using Joinpoint Regression.

RESULTS

We included 20 women (32 DIEP flaps and 59 dissected perforators). The mean deviation between mapped and reference coordinates was 1.00 (0.50-1.12) cm for CDU and 0.71 (0.50-1.12) cm for CTA. The learning curve of CDU mapping showed the breaking point after the seventh patient (≈ 21 localized perforators). After the breaking point, no significant differences between the deviations of both methods were found (p = 0.980).

CONCLUSION

A limited number of examinations were needed for the surgeon to learn CDU DIEA perforator mapping with accuracy similar to that of CTA mapping.

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.

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.

Persistently High Rates of Abdominal Computed Tomography Imaging Among Patients With Inflammatory Bowel Disease Who Present to the Emergency Department

Background

Recent guidelines recommended judicious use of abdominal computed tomography (CT) in the emergency department (ED) for inflammatory bowel disease. Trends in CT utilization over the last decade, including since the implementation of these guidelines, remain unknown.

Methods

We performed a single-centre, retrospective study between 2009 and 2018 to assess trends in CT utilization within 72 h of an ED encounter. Changes in the annual rates of CT imaging among adults with IBD were estimated by Poisson regression and CT findings by Cochran-Armitage or Cochran-Mantel Haenszel tests.

Results

A total of 3000 abdominal CT studies were performed among 14,783 ED encounters. CT utilization increased annually by 2.7% in Crohn’s disease (CD) (95% confidence interval [CI], 1.2 to 4.3; P = 0.0004), 4.2% in ulcerative colitis (UC) (95% CI, 1.7 to 6.7; P = 0.0009) and 6.3% in IBD unclassifiable (95% CI, 2.5 to 10.0; P = 0.0011). Among encounters with gastrointestinal symptoms, 60% with CD and 33% with UC underwent CT imaging in the final year of the study. Urgent CT findings (obstruction, phlegmon, abscess or perforation) and urgent penetrating findings alone (phlegmon, abscess or perforation) comprised 34% and 11% of CD findings, and 25% and 6% of UC findings, respectively. The CT findings remained stable overtime for both CD (P = 0.13) and UC (P = 0.17).

Conclusion

Our study demonstrated persistently high rates of CT utilization among patients with IBD who presented to the ED over the last decade. Approximately one third of scans demonstrated urgent findings, with a minority demonstrating urgent penetrating findings. Future studies should aim to identify patients in whom CT imaging is most appropriate.

Cohort profile: The Australian Paediatric Exposure to Radiation Cohort (Aust-PERC)

Although the carcinogenic effects of high-dose radiation are well-established, the risks at low doses, such as from diagnostic X-rays, are less well understood. Children are susceptible to radiation induced cancers, and in the last decade, several cohort studies have reported increased cancer risks following computed tomography (CT) scans in childhood. However, cohort studies can be limited by insufficient follow-up, indication bias, reverse causation, or by lack of organ doses from CT scans or other exposures. Aust-PERC is a retrospective cohort designed to study the effects of low-dose medical radiation exposure, primarily from CT scans, in young Australians. The cohort was ascertained using deidentified billing records from patients who were aged 0–19 years while enrolled in Medicare (Australia’s universal healthcare system) between 1985 and 2005. All procedures billed to Medicare in this age/time window that involved low-dose radiation were identified, and persons without such procedures were flagged as unexposed. The Aust-PERC cohort has been linked, using confidential personal identifiers, to the Australian Cancer Database and the National Death Index, on two occasions (to Dec. 2007 and Dec. 2012) by the responsible government agency (Australian Institute of Health and Welfare). Deidentified Medicare service records of all radiological procedures including CT scans, nuclear medicine (NM) scans and fluoroscopy and plain X-ray procedures have been available to derive estimated radiation doses in the cohort. Records of other medical and surgical procedures, together with demographic and socioeconomic variables are being used in analyses to assess biases arising from reverse causation and confounding. After excluding patients with errant records, 11 802 846 persons remained in the baseline cohort, with an average follow-up time of 22.3 years to December 2012. There were 275 489 patients exposed to diagnostic nuclear medicine scans and 688 363 patients exposed to CT scans before age 20 and before cancer diagnosis. Between 1 January 1985 and 31 December 2012, there were 105 124 deaths and 103 505 incident cancers. Dose-response analyses based on the relevant organ doses are underway for individual cancers, and we plan to extend the follow-up for another 8 years to Dec 2020. Analyses using this very large Aust-PERC cohort, with extended follow-up, will help to resolve international uncertainties about the causal role of diagnostic medical radiation as a cause of cancer.

Accounting for radiation exposure from previous CT exams while deciding on the next exam: What do referring clinicians think?

PURPOSE

To obtain clinicians' views of the need to account for radiation exposure from previous CT scans and the advisability of a regulatory mechanism to control the number of CT scans for an individual patient.

METHODS

A convenience survey was conducted by emailing a link to a three-question electronic survey to clinicians in many countries, mostly through radiology and radiation protection contacts.

RESULTS

505 responses were received from 24 countries. 293 respondents (58%) understand that current regulations do not limit the number of CT scans that can be prescribed for a single patient in a year. When asked whether there should be a regulation to limit the number of CT scans that can be prescribed for a single patient in one year, only a small fraction (143, 28%) answered 'No', 182 (36%) answered 'Maybe' and 166 (33%) answered 'Yes'. Most respondents (337; 67%) think that radiation risk should form part of the consideration when deciding whether to request a CT exam. A minority (138; 27%) think the decision should be based only on the medical indication for the CT exam. Comparison among the 4 countries (South Korea, Hungary, USA and Canada) with the largest number of respondents indicated wide variations in responses.

CONCLUSIONS

A majority of the surveyed clinicians consider radiation risk, in addition to clinical factors, when prescribing CT exams. Most respondents are in favor of, or would consider, regulation to control the number of CT scans that could be performed on a patient annually.

Pediatric Emergency MRI

There is an overall increase in the use of imaging in the pediatric emergency room setting, which is accompanied by a reduction in computed tomography examinations performed mainly due to the increased awareness of the risks of ionizing radiation. Advances in MRI technology have led to shortened scan time, decreased motion sensitivity, and improved spatial resolution. With increased access to MRI in the emergency room setting, the goal of this article is to review major applications of MR in pediatric emergency room patients.

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.

Augmented Reality in Surgery: A Scoping Review

Augmented reality (AR) is an innovative system that enhances the real world by superimposing virtual objects on reality. The aim of this study was to analyze the application of AR in medicine and which of its technical solutions are the most used. We carried out a scoping review of the articles published between 2019 and February 2022. The initial search yielded a total of 2649 articles. After applying filters, removing duplicates and screening, we included 34 articles in our analysis. The analysis of the articles highlighted that AR has been traditionally and mainly used in orthopedics in addition to maxillofacial surgery and oncology. Regarding the display application in AR, the Microsoft HoloLens Optical Viewer is the most used method. Moreover, for the tracking and registration phases, the marker-based method with a rigid registration remains the most used system. Overall, the results of this study suggested that AR is an innovative technology with numerous advantages, finding applications in several new surgery domains. Considering the available data, it is not possible to clearly identify all the fields of application and the best technologies regarding AR.

Dose-Response Effects of Low-Dose Ionizing Radiation on Blood Parameters in Industrial Irradiation Workers

While previous studies have focused on the health effects of occupational exposure of radiations on medical radiation workers, few have analyzed the dose-response relationship between low radiation doses and changes in blood parameters. Even fewer studies have been conducted on industrial worker populations. Using a prospective cohort study design, this study collected health examination reports and personal dose monitoring data from 705 industrial irradiation workers who underwent regular physical examinations at Dongguan Sixth People’s Hospital. The dose-response effects of low-dose ionizing radiation on blood parameters were assessed using a generalized linear model and restricted cubic spline model. Red blood cell counts decreased then increased, before decreasing again with increasing ionizing radiation. This was in contrast to the curve of the total platelet count after irradiation. Additionally, a radiation dose of 2.904 mSv was the turning point for the nonlinear curve of hemoglobin count changes. In conclusion, long-term, low-dose ionizing radiation affects blood cell levels in industrial irradiation workers. There is a nonlinear dose-response relationship between red blood cell, platelet, and hemoglobin counts and the cumulative radiation dose. These findings should alert radiation workers to seek preventive medical treatment before the occurrence of any serious hematopoietic disease.

Ionizing Radiation Exposure in Children with Vesicoureteral Reflux: Should We Be Alarmed?

Objectives Ionizing radiation imaging is commonly used for diagnosis and follow up in children with vesicoureteral reflux (VUR). We aim to measure the effective dose (mSv) in patients with VUR.

Methods We reviewed our electronic database of patients under 8-years-old with VUR. Primary endpoint was to calculate the effective radiation dose (ED). Absolute frequencies and percentages were reported for global qualitative variables. This study conducted a logistic regression model to calculate the odds ratio for radiation exposure. Analysis was performed using STATA version 14.0 (StataCorp LLC, College Station, TX, EEUU).

Results A total of 140 patients were found, 97 were assessed for eligibility. We included 59 patients in the final analysis. Mean age was 20 ± 17.9 months, 66% were females. Most cases of VUR were bilateral (44%) and high grade (93.4%). The lowest number of studies per patient was two, with a minimum radiation of 5.7 mSv. The highest radiation was estimated at 20.7 mSv corresponding to a total of five studies. Logistic regression showed that highest grades of VUR and age of first UTI episode were associated with higher ED (OR, 1.7; 95% CI, 0.87-3.31), (OR 1.02; 95% CI 0.97-1.07) respectively. A mean ED for children with VUR was estimated of 5.5 ± 3 mSv/year.

Conclusion In our study, the children with VUR were exposed to 5.5 mSv/year without counting the natural background radiation, which is alarming, and we believe should raise awareness worldwide in how we are unnecessarily diagnosing indolent VUR cases and following patients.

One Year of Lung Ultrasound in Children with SARS-CoV-2 Admitted to a Tertiary Referral Children's Hospital: A Retrospective Study during 2020-2021

During the COVID-19 pandemic, the lung ultrasound (LU) turned out to be a pivotal tool to study the lung involvement in the adult population, but the same was not well evaluated in children. We detected the LU patterns through an integrated approach with clinical−laboratory features in children hospitalized for COVID-19 in relation to the temporal trend of the Italian epidemic. We conducted a retrospective study which took place at a pediatric tertiary hospital from 15 March 2020 to 15 March 2021. We compared the characteristics of the initial phase of the first COVID-19 year—in the spring and summer (15 March−30 September 2020)—and those of the second phase—in the autumn and winter (1 October 2020−15 March 2021). Twenty-eight patients were studied both in the first and in the second phase of the first COVID-19 year. The disease severity score (DSS) was significantly greater in the second phase (p = 0.015). In the second phase of the first COVID-19 year, we detected a more significant occurrence of the following LU features than in the first phase: the irregular pleural line (85.71% vs. 60.71%; p = 0.035), the B-lines (89.29% vs. 60%; p = 0.003) and the several but non-coalescent B-lines (89.29% vs. 60%; p = 0.003). The LU score correlated significantly with the DSS, with a moderate relationship (r = 0.51, p < 0.001). The combined clinical, laboratory and ultrasound approaches might be essential in the evaluation of pulmonary involvement in children affected by COVID-19 during different periods of the pandemic.

High-performance reconstruction of CT medical images by using out-of-core methods in GPU

BACKGROUND AND OBJECTIVE

Since Computed Tomography (CT) is one of the most widely used medical imaging tests, it is essential to work on methods that reduce the radiation the patient is exposed to. Although there are several possible approaches to achieve this, we focus on reducing the exposure time through sparse sampling. With this approach, efficient algebraic methods are needed to be able to generate the images in real time, and since their computational cost is high, using high-performance computing is essential.

METHODS

In this paper we present a GPU (Graphics Processing Unit) software for solving the CT image reconstruction problem using the QR factorization performed with out-of-core (OOC) techniques. This implementation is optimized to reduce the data transfer times between disk, CPU, and GPU, as well as to overlap input/output operations and computations.

RESULTS

The experimental study shows that a block cache stored on main page-locked memory is more efficient than using a cache on GPU memory or mirroring it in both GPU and CPU memory. Compared to a CPU version, this implementation is up to 6.5 times faster, providing an improved image quality when compared to other reconstruction methods.

CONCLUSIONS

The software developed is an optimized version of the QR factorization for GPU that allows the algebraic reconstruction of CT images with high quality and resolution, with a performance that can be compared with state-of-the-art methods used in clinical practice. This approach allows reducing the exposure time of the patient and thus the radiation dose.

Lung ultrasonography decreases radiation exposure in newborns with respiratory distress: a retrospective cohort study

Chest X-ray (CXR) is commonly used as a first-line imaging method to determine the cause of respiratory distress in NICUs. The aim of the study was to retrospectively assess the decrease in the number of CXRs performed due to the use of lung ultrasonography on the first day of life for newborns with respiratory distress. Infants who were admitted to the NICU on the first day of life due to respiratory distress were enrolled in this study (ClinicalTrials.gov identifier NCT04722016) and divided into two groups: the study group (n = 104) included patients born between January 2019 and June 2020, and the historical control group (n = 73) included patients born between June 2017 and December 2018. As a first-line technique for lung imaging, only CXR had been used in the historical control group, whereas ultrasound had been preferred in the study group. The radiation dose to the newborns and the number of CXRs performed in the first day of life were compared between the two groups. Significant reductions in the number of CXRs performed and radiation exposure were observed in the study group. The radiation dose decreased from 5.54 to 4.47 µGy per baby when LUS was routinely used. The proportion of patients who underwent CXR decreased from 100 to 71.2%.Conclusion: We observed that using lung ultrasonography as a first-line evaluation method in neonates with respiratory distress decreased both the number of CXRs performed and radiation exposure. What is Known: • Chest X-ray is commonly used as a first line imaging method to diagnose the reason of respiratory distress in NICUs. • Lung ultrasound is a new diagnostic tool for lung imaging. What is New: • With the use of lung ultrasonography, radiation exposure of both newborns and healthcare workers can be reduced. • This retrospective study revealed that most of the babies with respiratory distress were treated without CXR.

Transradial Cerebral Angiography: Is it Feasible and Safe for Children?

PURPOSE

To investigate the feasibility and safety of transradial cerebral angiography (TRCA) in comparison to transfemoral cerebral angiography (TFCA) in the pediatric population.

MATERIALS AND METHODS

We retrospectively reviewed pediatric patients who underwent TRCA between January 2019 and July 2020. Patients with TFCA experience were examined. Pre- and post-procedural Doppler ultrasonography was performed to evaluate TRCA complications. To evaluate differences in radiation exposure between TRCA and TFCA, we investigated the radiation dose, dose area product (DAP), fluoroscopy time, and examination time.

RESULTS

Thirty-five patients (mean age, 13.8 years; 22 male) underwent TRCA, with 18 (mean age, 13.0 years; 10 male) experiencing TFCA. TRCA was successful in all cases without technical failure. Radiation exposure including radiation dose and DAP were significantly higher in the TRCA group (474.1 mGy and 8299.6 μGy m²) compared with the TFCA group (347.8 mGy and 6342.0 μGy m²). Fluoroscopy time and total examination time were significantly longer (145.1% and 32.6%) in TRCA (15.2 and 38.6 min) group compared with the TFCA group (6.2 and 29.1 min). Among the 26 patients who underwent post-procedural Doppler ultrasonography, five (19.2%) had complications after TRCA. Two (7.7%) patients showed radial artery stenosis, two (7.7%) had hematoma at the puncture site, and one (3.8%) showed thrombotic occlusion.

CONCLUSION

Although TRCA is a technically feasible and safe method in pediatric patients, high radiation exposure to TFCA must be considered. Therefore, it should be considered as an alternative method in those with unfavorable clinical situations for performing TFCA.

LEVEL OF EVIDENCE

Level 4, Case Series.

Quantifying cancer risk from exposures to medical imaging in the Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study: research methods and cohort profile

PURPOSE

The Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study is quantifying the association between cumulative radiation exposure from fetal and/or childhood medical imaging and subsequent cancer risk. This manuscript describes the study cohorts and research methods.

METHODS

The RIC Study is a longitudinal study of children in two retrospective cohorts from 6 U.S. healthcare systems and from Ontario, Canada over the period 1995-2017. The fetal-exposure cohort includes children whose mothers were enrolled in the healthcare system during their entire pregnancy and followed to age 20. The childhood-exposure cohort includes children born into the system and followed while continuously enrolled. Imaging utilization was determined using administrative data. Computed tomography (CT) parameters were collected to estimate individualized patient organ dosimetry. Organ dose libraries for average exposures were constructed for radiography, fluoroscopy, and angiography, while diagnostic radiopharmaceutical biokinetic models were applied to estimate organ doses received in nuclear medicine procedures. Cancers were ascertained from local and state/provincial cancer registry linkages.

RESULTS

The fetal-exposure cohort includes 3,474,000 children among whom 6,606 cancers (2394 leukemias) were diagnosed over 37,659,582 person-years; 0.5% had in utero exposure to CT, 4.0% radiography, 0.5% fluoroscopy, 0.04% angiography, 0.2% nuclear medicine. The childhood-exposure cohort includes 3,724,632 children in whom 6,358 cancers (2,372 leukemias) were diagnosed over 36,190,027 person-years; 5.9% were exposed to CT, 61.1% radiography, 6.0% fluoroscopy, 0.4% angiography, 1.5% nuclear medicine.

CONCLUSION

The RIC Study is poised to be the largest study addressing risk of childhood and adolescent cancer associated with ionizing radiation from medical imaging, estimated with individualized patient organ dosimetry.

Imaging Approaches to the Diagnosis of Vascular Diseases

PURPOSE OF REVIEW

Vascular imaging is a complex field including numerous modalities and imaging markers. This review is focused on important and recent findings in atherosclerotic carotid artery plaque imaging with an emphasis on developments in magnetic resonance imaging (MRI) and computed tomography (CT).

RECENT FINDINGS

Recent evidence shows that carotid plaque characteristics and not only established measures of carotid plaque burden and stenosis are associated independently with cardiovascular outcomes. On carotid MRI, the presence of a lipid-rich necrotic core (LRNC) has been associated with incident cardiovascular disease (CVD) events independent of wall thickness, a traditional measure of plaque burden. On carotid MRI, intraplaque hemorrhage (IPH) presence has been identified as an independent predictor of stroke. The presence of a fissured carotid fibrous cap has been associated with contrast enhancement on CT angiography imaging. Carotid artery plaque characteristics have been associated with incident CVD events, and advanced plaque imaging techniques may gain additional prominence in the clinical treatment decision process.

Gas in scattering media absorption spectroscopy as a potential tool in neonatal respiratory care

Gas in scattering media absorption spectroscopy (GASMAS) is a novel optical technology employing near-infrared light. It has a potential use in the medical setting as a monitoring and diagnostic tool by detecting molecular oxygen within gas pockets and thus may be a useful adjunct in respiratory monitoring. GASMAS has potential advantages over other monitoring devices currently used in clinical practice. It is a non-invasive, continuous, non-ionising technology and provides unique information about molecular oxygen content inside the lungs. GASMAS may have a future role in optimising respiratory management of neonates in different clinical scenarios such as monitoring cardiorespiratory transition in the delivery room, assessing surfactant deficiency, and optimising endotracheal tube positioning. This article aims to summarise current evidence exploring GASMAS application in a neonate, discuss possible clinical benefits, and compare with other devices that are currently used in neonatal care. IMPACT: This article presents a novel optical technique to measure lung oxygen concentrations that may have important clinical uses. This review summarises the current literature investigating the concept of optical lung oxygen measurement. Information from this review can guide researchers in future studies.

Validation of Deep Learning-based Augmentation for Reduced 18F-FDG Dose for PET/MRI in Children and Young Adults with Lymphoma

Purpose

To investigate if a deep learning convolutional neural network (CNN) could enable low-dose fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/MRI for correct treatment response assessment of children and young adults with lymphoma.

Materials and Methods

In this secondary analysis of prospectively collected data (ClinicalTrials.gov identifier: NCT01542879), 20 patients with lymphoma (mean age, 16.4 years ± 6.4 [standard deviation]) underwent ¹⁸F-FDG PET/MRI between July 2015 and August 2019 at baseline and after induction chemotherapy. Full-dose ¹⁸F-FDG PET data (3 MBq/kg) were simulated to lower ¹⁸F-FDG doses based on the percentage of coincidence events (representing simulated 75%, 50%, 25%, 12.5%, and 6.25% ¹⁸F-FDG dose [hereafter referred to as 75%_Sim, 50%_Sim, 25%_Sim, 12.5%_Sim, and 6.25%_Sim, respectively]). A U.S. Food and Drug Administration-approved CNN was used to augment input simulated low-dose scans to full-dose scans. For each follow-up scan after induction chemotherapy, the standardized uptake value (SUV) response score was calculated as the maximum SUV (SUV_max) of the tumor normalized to the mean liver SUV; tumor response was classified as adequate or inadequate. Sensitivity and specificity in the detection of correct response status were computed using full-dose PET as the reference standard.

Results

With decreasing simulated radiotracer doses, tumor SUV_max increased. A dose below 75%_Sim of the full dose led to erroneous upstaging of adequate responders to inadequate responders (43% [six of 14 patients] for 75%_Sim; 93% [13 of 14 patients] for 50%_Sim; and 100% [14 of 14 patients] below 50%_Sim; P < .05 for all). CNN-enhanced low-dose PET/MRI scans at 75%_Sim and 50%_Sim enabled correct response assessments for all patients. Use of the CNN augmentation for assessing adequate and inadequate responses resulted in identical sensitivities (100%) and specificities (100%) between the assessment of 100% full-dose PET, augmented 75%_Sim, and augmented 50%_Sim images.

Conclusion

CNN enhancement of PET/MRI scans may enable 50% ¹⁸F-FDG dose reduction with correct treatment response assessment of children and young adults with lymphoma.Keywords: Pediatrics, PET/MRI, Computer Applications Detection/Diagnosis, Lymphoma, Tumor Response, Whole-Body Imaging, Technology AssessmentClinical trial registration no: NCT01542879 Supplemental material is available for this article. © RSNA, 2021.

Potential role of artificial intelligence in craniofacial surgery

The field of artificial intelligence (AI) is rapidly advancing, and AI models are increasingly applied in the medical field, especially in medical imaging, pathology, natural language processing, and biosignal analysis. On the basis of these advances, telemedicine, which allows people to receive medical services outside of hospitals or clinics, is also developing in many countries. The mechanisms of deep learning used in medical AI include convolutional neural networks, residual neural networks, and generative adversarial networks. Herein, we investigate the possibility of using these AI methods in the field of craniofacial surgery, with potential applications including craniofacial trauma, congenital anomalies, and cosmetic surgery.

Impact of Active Esophageal Cooling on Fluoroscopy Usage During Left Atrial Ablation

Risks to collateral structures exist with radiofrequency (RF) ablation of the left atrium to obtain pulmonary vein isolation (PVI) for the treatment of atrial fibrillation. Passive luminal esophageal temperature (LET) monitoring is commonly utilized, but increasing data suggest limited benefits with LET monitoring. In contrast, active cooling of the esophagus has been shown to significantly reduce esophageal injury. Active cooling of the esophagus also avoids the need for stopping and repositioning an LET probe during use, which may reduce the need for fluoroscopy use. This study aimed to measure the impact on fluoroscopy use during RF ablation with esophageal cooling using a dedicated cooling device in a low-fluoroscopy practice. All patients who underwent PVI over a one-year timeframe by a single provider were analyzed. Patients undergoing PVI prior to the incorporation of an esophageal cooling protocol into standard ablation practice were treated with traditional LET monitoring. Patients treated after this point received active esophageal cooling, in which no LET monitoring is utilized. A total of 280 patients were treated; 91 patients were treated using LET monitoring, and 189 patients were treated with esophageal cooling. The mean total fluoroscopy time before the implementation of the esophageal cooling protocol in 91 patients was 194 seconds [standard deviation (SD): 182 seconds] per case, with a median of 144 seconds. The mean total fluoroscopy time after implementation in 189 patients was 126 seconds (SD: 120 seconds) per case with a median of 96 seconds, representing a reduction of 35% per case (p < 0.0001, Mann-Whitney U test). In this largest study to date of active esophageal cooling during PVI, a 35% reduction in fluoroscopy time compared with patients who received LET monitoring was found. This reduction was seen despite an already low fluoroscopy usage rate in place.