Radiation Exposure In Children Research Articles

Diagnostic value of CT scans in pediatric patients with acute non-traumatic altered mental status: a systematic review and meta-analysis.

Computed tomography (CT) scans are widely used for evaluating children with acute atraumatic altered mental status (AMS) despite concerns about radiation exposure and limited diagnostic yield. This study aims to assess the efficacy of CT scans in this population and provide evidence-based recommendations. A systematic review was conducted according to PRISMA guidelines. Comprehensive searches were performed in PubMed, Embase, Cochrane Library, Scopus, and Web of Science for studies involving pediatric patients with acute atraumatic AMS undergoing head CT scans. Two independent reviewers conducted the literature search, extracted data, and assessed study quality. From 4,739 identified studies, 13 met the inclusion criteria. The overall positive diagnostic yield of head CT scans was 35.9% (95% CI: 6.1%-65.7%). Subgroup analyses revealed that the diagnostic yield varied by clinical setting, age group, and presenting symptoms. Head CT scans are frequently performed in pediatric patients with AMS, but their diagnostic usefulness is limited. Evidence-based guidelines and risk stratification methods are necessary to improve imaging utilization and minimize radiation exposure risks. What is Known • Computed tomography (CT) scans are commonly used to evaluate pediatric patients with acute atraumatic altered mental status (AMS). • There are concerns about radiation exposure from CT scans, especially in children due to their increased sensitivity and longer life expectancy. • Previous studies suggest a low diagnostic yield of CT scans in certain pediatric conditions, indicating potential overuse. What is New • This systematic review and meta-analysis specifically assess the diagnostic value of CT scans in pediatric patients with acute atraumatic AMS. • Findings reveal a relatively low positive diagnostic yield, indicating that CT scans may be overutilized in this population. • Subgroup analyses highlight variability in outcomes based on clinical setting, patient age, and presenting symptoms. • The study underscores the need for evidence-based guidelines and risk stratification tools to optimize imaging decisions and reduce unnecessary radiation exposure in children.

Endoscopic injection vs anti-reflux surgery for moderate- and high-grade vesicoureteral reflux in children: a cost-effectiveness international study

Even if vesicoureteral reflux is a common condition in children, there are no guidelines about the best therapeutic approach. This study aims to compare the results of endoscopic injection and ureteral reimplantation in children with grade III, IV and V VUR. A multicenter retrospective study included children with grade III, IV and V VUR treated from 2003 to 2018 at three Departments of Pediatric Surgery. Patients were divided into Group A (endoscopic injections) and Group B (anti-reflux surgery), B1 (open, OUR), B2 (laparoscopic, LUR) and B3 (robot-assisted laparoscopic RALUR). Follow-up was at least 5 years. 400 patients were included, 232 (58%) in group A and 168 (42%) in group B. Mean age at surgery was 38.6 months [3.1–218.7]. Mean follow-up was 177.8 months [60–240]. Group A had shorter operative time than group B (P < 0.01); lower analgesic requirement (p < 0.05), shorter hospital stay (P < 0.05) and lower overall costs (p < 0.05), but higher postoperative PNPs (p < 0.01), lower success rate (p < 0.01) and higher redo-surgery percentage (p < 0.01). No differences in terms of postoperative complications, success rate and mean radiation exposure between the two groups. Endoscopy is associated with shorter operative time, shorter hospitalization and lower cost, also in case of multiple injections. Recurrence rate after surgery is lower meaning lower rate of re-hospitalization and radiation exposure for children.

7510 Use Of Tumor Markers And Surgery In The Management Of Medullary Thyroid Cancer During Pregnancy

Abstract Disclosure: M. Garver: None. C. Vaz: None. Introduction: Thyroid cancer is the second most diagnosed cancer during pregnancy, predominantly differentiated thyroid malignancies. [1] MTC during pregnancy is rare and challenging to manage due to its aggressive nature. We describe the successful diagnosis and management of MTC during pregnancy. Clinical Case: A 28 yo woman presented with a rapidly growing neck lump for 2 months with an associated unintentional 10lb weight loss and without compressive symptoms. She had no history of childhood radiation exposure or family history of thyroid cancer. Physical exam revealed a hard L lobe thyroid nodule without palpable lymphadenopathy. The patient was 5 weeks pregnant at the time. A neck US revealed a 4.2x2.7x2.0 cm L solid isoechoic thyroid nodule with punctate echogenic foci and microcalcifications. The nodule was classified as TIRADS 4 and ATA high suspicion. FNA noted Bethesda IV with positive IHC stains for chromogranin and calcitonin. Afirma MTC classifier was positive, confirming diagnosis of MTC. At 7 weeks gestation, calcitonin was markedly elevated at 3508 pg/mL (n &amp;lt;5 pg/mL), CEA 29.5 ng/mL (n &amp;lt;2.5 ng/mL) and calcium 10.3mg/dL (8.6-10.2mg/dL). Plasma normetanephrines were elevated to176 pg/mL (n &amp;lt;148 pg/mL) with normal metanephrines 28 pg/mL (n &amp;lt;57 pg/mL) and normal 24-hour urine metanephrines. CT neck revealed 3.2x2.8cm L thyroid nodule without cervical lymphadenopathy. Due to pregnancy status, additional imaging to assess for metastatic disease was deferred until after delivery. Genetic testing did not identify mutations within the thyroid cancer panel including APC, CHEK2, DICER1, MEN1, PRKAR1A, PTEN, RET, SDHB, SDHD, and TP53. The patient underwent total thyroidectomy with neck dissection at 19 weeks gestation without complication. Two weeks postoperative Calcitonin was 2 pg/mL(n &amp;lt;5 pg/mL) and CEA was undetectable. Conclusions: The effect of pregnancy on MTC is not well studied because of low incidence. Guidelines on the timing of surgery for MTC diagnosed during pregnancy are lacking. While evidence confirms that surgery can be safely postponed until after delivery for low risk differentiated thyroid malignancies, there is no consensus on timing of surgery for MTC. Given the aggressive nature of MTC, along with marked elevation of calcitonin and CEA in this case, surgery was performed in the 2nd trimester with excellent outcome. Data is conflicting on accuracy of calcitonin and CEA during pregnancy, with some reports suggesting falsely high levels due to pregnancy. The sharp decline in calcitonin and CEA 2 weeks postoperatively suggested these were truly elevated due to MTC and unaffected by pregnant status. We suggest that calcitonin and CEA be followed similar to non-pregnant cases with MTC. Resources: 1.Khaled, H. M., Lahloubi, N. A., &amp; Rashad, N. (2016). A review on thyroid cancer during pregnancy: Multitasking is required. Journal of Advanced Research, 7(4), 565–570. Presentation: 6/2/2024

FDG-PET/MRI in the presurgical evaluation of pediatric epilepsy.

In patients with drug-resistant epilepsy, difficulties in identifying the epileptogenic zone are well known to correlate with poorer clinical outcomes post-surgery. The integration of PET and MRI in the presurgical assessment of pediatric patients likely improves diagnostic precision by confirming or widening treatment targets. PET and MRI together offer superior insights compared to either modality alone. For instance, PET highlights abnormal glucose metabolism, while MRI precisely localizes structural anomalies, providing a comprehensive understanding of the epileptogenic zone. Furthermore, both methodologies, whether utilized through simultaneous PET/MRI scanning or the co-registration of separately acquired PET and MRI data, present unique advantages, having complementary roles in lesional and non-lesional cases. Simultaneous FDG-PET/MRI provides precise co-registration of functional (PET) and structural (MR) imaging in a convenient one-stop-shop approach, which minimizes sedation time and reduces radiation exposure in children. Commercially available fusion software that allows retrospective co-registration of separately acquired PET and MRI images is a commonly used alternative. This review provides an overview and illustrative cases that highlight the role of combining 18F-FDG-PET and MRI imaging and shares the authors' decade-long experience utilizing simultaneous PET/MRI in the presurgical evaluation of pediatric epilepsy.

Failure to Significantly Reduce Radiation Exposure in Children with Suspected Appendicitis in the United States

BackgroundUltrasound (US) or magnetic resonance imaging (MRI) is recommended over computed tomography (CT) as the initial imaging modality when considering a diagnosis of appendicitis in children. This reduces unnecessary radiation exposure and has excellent accuracy. We hypothesized a significant increase in US utilization and a reduction in CT utilization in hospitals across the United States. MethodsWe retrospectively reviewed NSQIP-P data from 2015 to 2021 for patients <18 years undergoing appendectomy for acute appendicitis. Rates of US, CT, and MRI usage were compared between NSQIP-P hospitals and referring non-NSQIP-P hospitals. ResultsOf the 115,186 children included, 66,303 (57.6%) were imaged in NSQIP-P hospitals, 37,962 (33.0%) in non-NSQIP-P hospitals, and 7947 (6.9%) in both. US alone was used in 53.3%, followed by CT alone in 25.1%, both US + CT in 16.4%, and MRI ± CT/US in 2.6%. Non-NSIQP-P hospitals used less US than NSQIP-P centers (38.6% vs 90.8%, P < 0.0001) and more CT (74.0% vs 25.4%, P < 0.0001). From 2015 to 2021, overall US utilization increased from 68.5% to 72.3% (p < 0.0001) while CT utilization remained unchanged (43.1%–43.2%, P = 0.07). US use increased in non-NSQIP-P centers (18.8%–25.7%, P < 0.0001) but not in NSQIP-P (71.7% vs 70.9%, p = 0.28), while CT alone decreased in both (NSQIP-P: 10.1%–7.7%, P < 0.0001; non-NSQIP-P: 71.0%–59.8%, P < 0.0001). ConclusionUS and MRI remain underutilized in diagnosing pediatric appendicitis, especially in non-NSQIP-P hospitals. Trends show modest increase in US utilization; however, CT alone remains a highly used modality in non-NSQIP-P hospitals. Adopting diagnostic strategies from NSQIP-P centers could optimize diagnostic imaging in children. Level of EvidenceIII.

Thyroid cancer incidence in cohorts exposed in childhood to 131I released during the Windscale nuclear reactor accident at Sellafield, England, in 1957

A fire in one of the Windscale nuclear reactors at Sellafield (Cumbria, England) in October 1957 released 1,800 TBq of 131I (half-life, 8 days) to atmosphere. Measurements of 131I activity in thyroids of exposed children showed typical thyroid doses of tens of milligray, but with some exceeding 100 mGy. Radiation exposure in childhood is known to increase the risk of thyroid cancer. Consequently, an investigation was conducted into whether raised numbers of thyroid cancer cases occurred in those exposed to 131I as young children in Cumbria. A database of Cumbrian births from 1950 onwards allowed cohorts of 56,086 births during 1950–1958 and 137,444 births during 1959–1980 to be constructed, periods including children potentially exposed and unexposed, respectively, to 131I. Three areas of Cumbria with different 131I contamination levels were identified from monitoring data, and births assigned to these three areas for the two periods of birth. Members of these six sub-cohorts were linked to incident thyroid cancer cases in Great Britain during 1981–2020 using national cancer registration databases, providing thyroid cancer incidence rates. Incidence rate ratios (IRRs), with the lowest contamination area as a reference, were computed. No IRR differed discernibly from unity. For births during 1950–1958, the IRR for the combined highest and intermediate 131I contamination areas was 0.68 (95% confidence interval: 0.24, 1.56), and no case of thyroid cancer was found in the small cohort born in the highest contamination area. In conclusion, no increased risk of thyroid cancer in those exposed to 131I as young children in Cumbria in 1957 was detected. This study adds to the evidence on the long-term risk of thyroid cancer following childhood exposure to low and moderate levels of 131I, such as occurred following the Fukushima nuclear accident in 2011.

Pediatric Carotid Injury after Blunt Trauma and the Necessity of CT and CTA-A Narrative Literature Review.

Background: Blunt carotid injury (BCI) in pediatric trauma is quite rare. Due to the low number of cases, only a few reports and studies have been conducted on this topic. This review will discuss how frequent BCI/blunt cerebrovascular injury (BCVI) on pediatric patients after blunt trauma is, what routine diagnostics looks like, if a computed tomography (CT)/computed tomography angiography (CTA) scan on pediatric patients after blunt trauma is always necessary and if there are any negative health effects. Methods: This narrative literature review includes reviews, systematic reviews, case reports and original studies in the English language between 1999 and 2020 that deal with pediatric blunt trauma and the diagnostics of BCI and BCVI. Furthermore, publications on the risk of radiation exposure for children were included in this study. For literature research, Medline (PubMed) and the Cochrane library were used. Results: Pediatric BCI/BCVI shows an overall incidence between 0.03 and 0.5% of confirmed BCI/BCVI cases due to pediatric blunt trauma. In total, 1.1-3.5% of pediatric blunt trauma patients underwent CTA to detect BCI/BCVI. Only 0.17-1.2% of all CTA scans show a positive diagnosis for BCI/BCVI. In children, the median volume CT dose index on a non-contrast head CT is 33 milligrays (mGy), whereas a computed tomography angiography needs at least 138 mGy. A cumulative dose of about 50 mGy almost triples the risk of leukemia, and a cumulative dose of about 60 mGy triples the risk of brain cancer. Conclusions: Given that a BCI/BCVI could have extensive neurological consequences for children, it is necessary to evaluate routine pediatric diagnostics after blunt trauma. CT and CTA are mostly used in routine BCI/BCVI diagnostics. However, since radiation exposure in children should be as low as reasonably achievable, it should be asked if other diagnostic methods could be used to identify risk groups. Trauma guidelines and clinical scores like the McGovern score are established BCI/BCVI screening options, as well as duplex ultrasound.

Prospective assessment of entrance skin dose and targets for radiation reduction during abdominal plain films in pediatric urology patients

Abdominal radiographs are frequently used for evaluation of bowel and bladder dysfunction in pediatric urology. However, the dose of radiation delivered with each study is estimated from machine settings as opposed to measurement of the true entrance skin dose. In addition, the correlation of radiographic constipation with patient symptoms has been questioned. To evaluate the practices for obtaining abdominal radiographs and the true entrance skin dose of radiation for each examination in order to identify targets for radiation reduction. Pediatric urology patients were prospectively enrolled from June 2022 through June 2023. Dosimeters were attached to the navel to collect entrance skin doses from single view abdominal x-ray. Estimated doses were compared to measured entrance skin dose as well as patient characteristics. Exam parameters were evaluated to identify targets for radiation reduction. A total of 75 patients were recruited for this study with a median age of 10.0 years (IQR 6-14). Most evaluations were done to assess for bowel and bladder dysfunction (68 exams, 91%). The protocol for exams was not standardized resulting in 27% of patients undergoing a medium or high dose strength and 55% undergoing 1 or more image. The median estimated dose was 0.63mGy (IQR 0.3-1.2mGy). The median measured dose was 0.77mGy (IQR 0.31-2.01mGy) which was significantly different than the estimations (p<0.001). The estimated dose, measured dose and estimate error were all found to be positively correlated with patient characteristics including age and body mass index (See Figure). Increasing age and body mass index also showed a higher likelihood of increased dose strength and image acquisition. The measured entrance skin dose of radiation is significantly higher than prior estimates. The measured dose but also the estimate error increased with patient age and size which is likely related to higher settings used for image acquisition as patients age. Standardized protocols using low dose settings and limiting image acquisition to the pelvis may reduce radiation exposure in children with bowel and bladder dysfunction while providing adequate diagnostic data. Radiation dose for abdominal radiographs is higher than previously estimated. Older and larger children received higher doses which may be mediated by increased dose strength and image acquisition. Standardization of protocols could lower radiation exposure.

Characteristics and immune checkpoint status of radioiodine-refractory recurrent papillary thyroid carcinomas from Ukrainian Chornobyl Tissue Bank donors.

The radioiodine-refractory (RAI-R) recurrent papillary thyroid carcinomas (PTCs) are more frequent in elderly patients and have an unfavorable prognosis. Data on the prevalence and characteristics of RAI-R recurrent PTCs in patients of young and middle age with or without a history of radiation exposure in childhood are poorly described. The aim of the current study was: i) to determine the frequency of RAI-R recurrent PTCs among donors of the Chornobyl Tissue Bank (CTB) and analyze the clinicopathological features of primary tumors (PTs), primary metastases (PMTSs), recurrent metastases (RMTSs) and risk factors for RMTS, and ii) to determine the immune checkpoint status (ICS) of the RAI-R recurrent PTCs and to assess the factors associated with ICS positivity. Sixty RAI-R recurrent PTCs (46 exposed to radiation and 14 non-exposed, 2.5% of all cases registered with the CTB) from the Ukrainian patients aged up to 48 years were identified. The clinicopathological characteristics of the PTs moderately to weakly resembled those of the PMTS and RMTS from the same patients while the metastatic tissues were highly similar. The multivariate model of RMTS included the dominant solid-trabecular growth pattern of the PT, cystic changes, N1b metastases, and the probability of a causation (POC) of PTC by radiation as risk factors. Among these factors, the lateral PMTS (N1b) had the strongest effect. The longer period of latency (a POC component) was the second statistically significant characteristic. ICS percent agreement between the PT and RAI-R RMTS was 91.5%; 23.7% of PTs and 28.8% of RMTSs had positive ICS (positive PD-L1 tumor epithelial cells (TECs) and positive PD-L1/PD1 tumor-associated immune cells). ICS positivity of PTs was associated with pronounced oncocytic changes and high density of the p16INK4A-positive TECs in the invasive areas of PTs. In RMTSs, ICS positivity was associated with pronounced oncocytic changes and Ki-67 labeling index ≥ 4.5% of PTs, and the dominant solid-trabecular growth pattern, Ki-67 labeling index ≥ 7.6% and p16INK4A-positivity of RMTS. The findings are of clinical relevance and may be useful for developing individual treatment approaches for patients with RAI-R recurrent PTCs possibly involving immunotherapy.

Point-of-care ultrasound as a diagnostic tool in respiratory assessment in awake paediatric patients: a comparative study

BackgroundChest X-ray (CXR) has typically been the main investigation in children with suspected respiratory pathology. Recent advances in lung point-of-care ultrasound (POCUS) have shown the potential for it to be...

Risk of hematological malignancies from CT radiation exposure in children, adolescents and young adults

Over one million European children undergo computed tomography (CT) scans annually. Although moderate- to high-dose ionizing radiation exposure is an established risk factor for hematological malignancies, risks at CT examination dose levels remain uncertain. Here we followed up a multinational cohort (EPI-CT) of 948,174 individuals who underwent CT examinations before age 22 years in nine European countries. Radiation doses to the active bone marrow were estimated on the basis of body part scanned, patient characteristics, time period and inferred CT technical parameters. We found an association between cumulative dose and risk of all hematological malignancies, with an excess relative risk of 1.96 (95% confidence interval 1.10 to 3.12) per 100 mGy (790 cases). Similar estimates were obtained for lymphoid and myeloid malignancies. Results suggest that for every 10,000 children examined today (mean dose 8 mGy), 1–2 persons are expected to develop a hematological malignancy attributable to radiation exposure in the subsequent 12 years. Our results strengthen the body of evidence of increased cancer risk at low radiation doses and highlight the need for continued justification of pediatric CT examinations and optimization of doses.

Thyroid cancer risk after radiation exposure in adults-systematic review and meta-analysis.

Notably, the growing use of radionuclear technology, especially in diagnostic and therapeutic procedures involving radiation exposure, raises concerns about the health effects of radiation. Although epidemiological studies have provided strong evidence for elevated thyroid cancer risk after radiation exposure in childhood, the risk of thyroid cancer associated with adult exposure remains to be investigated. We conducted a systematic review and meta-analysis of relevant studies on the risk of developing thyroid cancer after radiation exposure in adulthood. The PubMed and Web of Science databases were used to select eligible articles. After screening, a total of 15 studies were identified in which estimates of the standardized incidence ratio (SIR) and the relative risk (RR) of thyroid cancer were available in 8 and 11 studies, respectively. The overall SIR estimated by the random effects model was 2.19 [95% confidence interval (CI), 1.54, 3.10]. Cochran's Q test showed significant heterogeneity in the SIRs (Q= 178, P< 0.0001). The overall RR at 10mGy was 1.0038 (95% CI, 0.9991, 1.0085), with no significant heterogeneity (Q= 9.30, P= 0.5041). The total SIR, as well as that from each study, indicated a statistically significant excess, which could be related to screening bias. Radiation-related thyroid cancer risk was elevated in a few studies; however, the overall estimate of the RR at 10mGy was not significant. This study demonstrates no strong epidemiological evidence for the risk of thyroid cancer in radiation exposure during adulthood; however, further research is needed.

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

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

Sono-Elastography: An Ultrasound Quantitative Non-Invasive Measurement to Guide Bacterial Pneumonia Diagnosis in Children.

Lung ultrasound (LUS) is, at present, a standard technique for the diagnosis of acute lower respiratory tract infections (ALRTI) and other lung pathologies. Its protocolised use has replaced chest radiography and has led to a drastic reduction in radiation exposure in children. Despite its undeniable usefulness, there are situations in which certain quantitative measurements could provide additional data to differentiate the etiology of some pulmonary processes and thus adapt the treatment. Our research group hypothesises that several lung processes such pneumonia may lead to altered lung tissue stiffness, which could be quantified with new diagnostic tests such as lung sono-elastography (SE). An exhaustive review of the literature has been carried out, concluding that the role of SE for the study of pulmonary processes is currently scarce and poorly studied, particularly in pediatrics. The aim of this review is to provide an overview of the technical aspects of SE and to explore its potential usefulness as a non-invasive diagnostic technique for ALRTI in children by implementing an institutional image acquisition protocol.

Implementation of ultrasound and fast magnetic resonance imaging pathway reduces computed tomography utilization in children with suspected appendicitis.

Computed tomography (CT) is still used in the imaging diagnosis of acute appendicitis in children at many hospitals. We implemented an ultrasound (US) and fast magnetic resonance imaging (MRI) pathway for suspected appendicitis at our institution with the goal of reducing radiation exposure in children. All children (< 18years old) who underwent appendectomy between January 2011 and July 2021 were reviewed. Data were collected on all imaging studies performed. In December 2015, we initiated an imaging pathway for suspected acute appendicitis. US was the initial imaging study, and a rapid protocol MRI was performed if US was equivocal. Those could not tolerate MRI underwent CT. We evaluated the difference in percentage of patients who underwent CT before and after pathway initiation. 554 patients who underwent appendectomy did not have prior imaging studies on presentation to our hospital and were included in analysis. After initiating the pathway, the use of abdominal US increased from 87% (220 of 254) to 97% (291 of 300, p < 0.0001) and the use of MRI increased by 100% (0 MRIs pre-protocol, 90 of 300 patients post-protocol, p < 0.0001). CT utilization decreased significantly from 32% (82 of 254) to 2% (6 of 300, p < 0.0001). Embracing a new US and rapid MRI pathway to evaluate pediatric patients with suspected acute appendicitis resulted in significant reduction in CT utilization and therefore radiation exposure.

Radiation dose reduction using spectral shaping in pediatric non-contrast sinus CT.

CT is the standard imaging technique to evaluate pediatric sinuses. Given the potential risks of radiation exposure in children, it is important to reduce pediatric CT dose and maintain image quality. To study the utility of spectral shaping with tin filtration to improve dose efficiency for pediatric sinus CT exams. A head phantom was scanned on a commercial dual-source CT using a conventional protocol (120kV) and a proposed 100kV with a 0.4-mm tin filter (Sn100 kV) protocol for comparison. Entrance point dose (EPD) of eye and parotid gland region was measured by an ion chamber. Sixty pediatric sinus CT exams (33 acquired with 120kV, 27 acquired with Sn100 kV) were retrospectively collected. All patient images were objectively measured for image quality and blindly reviewed by 4 pediatric neuroradiologists for overall noise, overall diagnostic quality, and delineation of 4 critical paranasal sinus structures, using a 5-point Likert scale. Phantom CTDIvol from Sn100 kV is 4.35mGy, compared to CTDIvol of 5.73mGy from 120kV at an identical noise level. EPD of sensitive organs decreases in Sn100 kV (e.g., right eye EPD 3.83±0.42mGy), compared to 120kV (5.26±0.24mGy). Patients in the 2 protocol groups were age and weight (unpaired T test P>0.05) matched. The patient CTDIvol of Sn100 kV (4.45±0.47mGy) is significantly lower than 120kV (5.56±0.48mGy, unpaired T test P<0.001). No statistically significant difference for any subjective readers' score (Wilcoxon test P>0.05) was found between the two groups, indicating proposed spectral shaping provides equivalent diagnostic image quality. Phantom and patient results demonstrate that spectral shaping can significantly reduce radiation dose for non-contrast pediatric sinus CT without compromising diagnostic quality.

Emerging role of computed tomography coronary angiography in evaluation of children with Kawasaki disease.

Coronary artery abnormalities are the most important complications in children with Kawasaki disease (KD). Two-dimensional transthoracic echocardiography currently is the standard of care for initial evaluation and follow-up of children with KD. However, it has inherent limitations with regard to evaluation of mid and distal coronary arteries and, left circumflex artery and the poor acoustic window in older children often makes evaluation difficult in this age group. Catheter angiography (CA) is invasive, has high radiation exposure and fails to demonstrate abnormalities beyond lumen. The limitations of echocardiography and CA necessitate the use of an imaging modality that overcomes these problems. In recent years advances in computed tomography technology have enabled explicit evaluation of coronary arteries along their entire course including major branches with optimal and acceptable radiation exposure in children. Computed tomography coronary angiography (CTCA) can be performed during acute as well as convalescent phases of KD. It is likely that CTCA may soon be considered the reference standard imaging modality for evaluation of coronary arteries in children with KD.

The burden of radiation exposure in children requiring percutaneous nephrolithotomy

Children undergoing investigation and management for complex upper tract urolithiasis often require multimodal imaging. The significance of related radiation exposure in stone care pathways has received little attention in the published literature. Medical records of paediatric patients undergoing percutaneous nephrolithotomy were retrospectively analysed to ascertain the modalities used and determine extent of radiation exposure occurring during each care pathway. Radiation dose simulation and calculation was performed a priori. The cumulative effective dose (mSv) and cumulative organ dose (mGy) for radiosensitive organs was calculated. A total of 140 imaging studies were included from the care pathways of 15 children with complex upper tract urolithiasis. Median follow-up was 9.6 years (range: 6.7-16.8 years). The average number of imaging studies with ionising radiation per patient was nine, with a cumulative effective dose of 18.3mSv across all modalities. The most common modalities were: mobile fluoroscopy (43%), x-ray (24%), and computed tomography (18%). The cumulative effective dose per study type was greatest for CT (4.09mSv), followed by fixed and mobile fluoroscopy (2.79mSv and 1.82mSv, respectively). There is high general awareness of radiation exposure involved in CT scanning with resultant caution in employing this modality in paediatric patients. However, the significant radiation exposure relating to fluoroscopy (whether fixed or mobile) is less well documented in children. We recommend implementing steps to minimise radiation exposure by optimisation and avoidance of certain modalities where possible. Paediatrics urologists must employ strategies to minimise radiation exposure in children with urolithiasis, given the significant exposures encountered.

Usefulness of large beam-shaping filters at different tube voltages of newborn chest CT.

To investigate optimizing the use of different beam shaping filters (viz. small, medium and large) when using different tube voltages during the newborn chest computed tomography (CT) on a GE Lightspeed VCT scanner. We used pediatric anthropomorphic phantoms with a 64 detector-row CT scanner while scanning the chest. A real-time skin dosimeter (RD - 1000; Trek Corporation, Kanagawa, Japan) was positioned into the phantom center of the body, the surface of the body back, and the right and left mammary glands. We performed and compared six scan protocols using small, medium, and large beam shaping filters at 80 and 120 kVp protocols. There were no significant differences in the image noise for the chest scan among the different beam shaping filters. By using the large beam shaping filter at 80 kVp, it was possible to reduce the exposure dose by 5% in comparison with the small beam shaping filter, and by 10% in comparison with the medium beam shaping filter. By using the large beam shaping filter at 120 kVp, it was possible to reduce the exposure dose by 15% in comparison with the small beam shaping filter and by 20% in comparison with the medium beam shaping filter (p < 0.01). The large beam shaping filter had the most dose reduction effect during newborn chest CT on a GE Lightspeed VCT scanner. The additional copper filtration being present in the large bowtie filter of the GE Lightspeed CT scanner when using different tube voltages is more effective in reducing radiation exposure in children.

Radiation exposure estimation in pediatric patients during computed tomography imaging procedures

Computed tomography (CT) procedures are the largest source of medical radiation exposure in children and adults. Numerous children undergo high-radiation-dose examinations due to the increasing utilization of CT in children and the wide range of radiation doses. It is therefore necessary to protect pediatric patients, because of their higher sensitivity to ionizing radiation. This study aimed to establish a multicenter cohort of pediatric patients who received CT scans and predict the radiation-related cancer risk. Ninety-five patients who underwent various CT scans [brain 64 (67.4%), chest 14 (14.7%), abdomen 17 (17.9%)] were referred to one of three hospitals. All patients were examined using one of three identical multi-detector CT machines (Toshiba Aquilion 64) according to standard departmental imaging protocols. The average effective doses per scan for brain, chest, and abdominal procedures were 49.7, 34, and 40 mSv, respectively. Dose-reduction measures might significantly decrease the number of radiation-induced malignancies in children.