Predicted cancer risks induced by computed tomography examinations during childhood, by a quantitative risk assessment approach

Primary Mold-Active Antifungal Prophylaxis Decreases the Need for Chest Computed Tomography Scans in Patients with Acute Lymphoblastic Leukemia

Current guidelines recommend computed tomography (cCT) scans of the chest in children with leukemia following 96 h of the onset of idiopathic neutropenia to eliminate pulmonary invasive fungal infections (IFIs). However, cCT exposes some children who are at a very high risk of developing secondary cancers to radiation. We aimed to determine the effect of antifungal prophylaxis (AFP) with voriconazole (VCZ) on the need for cCT scans in children with acute lymphoblastic leukemia (ALL) to eliminate pulmonary IFIs during chemotherapy. We retrospectively screened all patients' data from their electronic charts. Children who were diagnosed as having ALL before February 2013 and did (AFP group) or did not (NoP group) receive AFP were divided into two groups and compared regarding cCT scans and relapse-mortality rates. Ninety-six children were diagnosed before February 2013 and did not receive primary AFP and 146 children were administered VCZ following a diagnosis of ALL. There were no significant demographic differences between the groups. A total of 128 cCTs had been required in 62 children in the NoP group, compared with 64 cCTs in 52 children in the AFP group. The percentage of the patients who had required at least one chest CT scan and the mean number of cCT scans in the NoP group were significantly higher compared with the AFP group. Proven-probable IFIs and relapse-mortality rates were higher in the NoP group compared with the AFP group. Mold-active AFP revealed a significant decrease in the need for cCT scans in children with ALL.

Venous 3D Phase Contrast Magnetic Resonance Angiography Increases Diagnostic Certainty in Children with Ventriculoperitoneal Shunt and Suspected Shunt Failure

BACKGROUND

Clinical symptoms in children with suspected malfunction of ventriculoperitoneal shunt may not be specific and difficult to interpret. The presence or absence of ventricular enlargement on magnetic resonance imaging (MRI) does not reliably predict raised intracranial pressure (ICP) in these patients. Therefore, the aim was to investigate the diagnostic utility of 3D venous phase-contrast MR angiography (vPCA) in these patients.

MATERIALS

The MR studies of two groups of patients at two different examination dates were retrospectively analyzed; one group without clinical symptoms on both examinations and one with symptoms of shunt dysfunction on one examination receiving surgery. Both MRI examinations had to have been performed including axial T2 weighted (T2-w) images and 3D vPCA. Two (neuro)radiologists evaluated T2-w images alone and in combination with 3D vPCA in terms of suspected elevated ICP. Interrater reliability, sensitivity and specificity were assessed.

RESULTS

Compression of venous sinuses was seen significantly more often in patients with shunt failure (p = 0.00003). Consequently, evaluation of 3D vPCA and T2-w images increases sensitivity to 0.92/1.0 compared to T2-w images alone with 0.69/0.77, the interrater agreement for the diagnosis of shunt failure rises from κ = 0.71 to κ = 0.837. Concerning imaging markers, three groups could be identified in children with shunt failure.

CONCLUSION

In accordance with the literature, the results show that ventricular morphology alone is an unreliable marker for elevated ICP in children with shunt malfunction. The findings confirmed 3D vPCA as a valuable supplemental diagnostic tool improving diagnostic certainty for children with unchanged ventricular size in cases of shunt failure.

Estimation of cancer risks due to chest radiotherapy treatment planning computed tomography (CT) simulations

The objective of our study was to determine organ doses to estimate the lifetime attributable risk (LAR) of cancer incidence related to chest tomography simulations for Radiotherapy Treatment Planning (RTTP) using patient-specific information. Patient data were used to calculate organ doses and effective dose. The effective dose (E) was calculated by two methods. First, to calculate effective dose in a standard phantom, the collected dosimetric parameters were used with the ImPACT CT Patient Dosimetry Calculator and E was calculated by applying related correction factors. Second, using the scanner-derived Dose Length Product, LARs were computed using the US National Academy of Sciences (BEIR VII) model for age- and sex-specific risks at each exposure. DLP, CTDI_vol, and scan length were 507 ± 143 mGy.cm, 11 ± 4 mGy, and 47 ± 7 cm, respectively. The effective dose was 10 ± 3 mSv using ImPACT patient dosimetry calculator software and 9 ± 2 mSv using the scanner-derived Dose Length Product. The LAR of cancer incidence for all cancers, all solid cancers and leukemia were 65 ± 29, 62 ± 27, 7 ± 2 cases per 100,000 individuals, respectively. Radiation exposure from the usage of CT for radiotherapy treatment planning (RTTP) causes non-negligible increases in lifetime attributable risk. The results of this study can be used as a guide by physicians to implement strategies based on the As Low As Reasonably Achievable (ALARA) principle that lead to a reduction dose without sacrificing diagnostic information.

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.

Application of intentional facial nerve stimulation during cochlear implantation as an electrophysiological tool to estimate the intracochlear electrode position

This proof of concept describes the use of evoked electromyographic (EMG) activation of the facial nerve for intraoperative monitoring of the electrode insertion during cochlear implantation (CI). Intraoperative EMG measurements from the facial nerve were conducted in nine patients undergoing CI implantation. Electric current pulses were emitted from contacts on the CI array during and immediately after electrode insertion. For control, the results of EMG measurements were compared to postoperative flat panel volume computed tomography scans with secondary reconstruction (fpVCT_SECO). During insertion, the EMG response evoked by the electrical stimulation from the CI was growing with the stimulating contact approaching the facial nerve and declined with increasing distance. After full insertion, contacts on the apical half of the CI array stimulated higher EMG responses compared with those on the basal half. Comparison with postoperative imaging demonstrated that electrode contacts stimulating high EMG responses had the shortest distances to the facial nerve. It could be demonstrated that electrically evoked EMG activation of the facial nerve can be used to monitor the progress during CI electrode insertion and to control the intracochlear electrode position after full insertion.

Effect of Alvarado Score on the Negative Predictive Value of Nondiagnostic Ultrasound for Acute Appendicitis

Background:

The purposes of this study were to calculate the negative predictive value (NPV) of nondiagnostic ultrasound (US) in patients with suspected appendicitis and to identify the clinical factors that were associated with the nondiagnostic US.

Methods:

We conducted a retrospective review of 412 patients who had graded-compression appendiceal US performed during January 2017 and December 2017. The NPV of the nondiagnostic US in combination with clinical parameters was calculated. Multivariate regression analysis was used to determine the independent predictors for the nondiagnostic US.

Results:

The US exam was nondiagnostic in 64.8% of the patients, giving an NPV of 70.8%. The NPV of nondiagnostic US increased to 96.2% in patients who had an Alvarado score of <5. The patients who did not have migratory pain, did not have leukocytosis, and had a pain score of <7 were more likely to have a nondiagnostic US study (P < 0.001).

Conclusion:

Alvarado score had an inverse effect on the NPV of nondiagnostic appendiceal US. Patients who had nondiagnostic US and Alvarado score of <5 were very unlikely to have appendicitis. Active clinical observation or re-evaluation rather than immediate computed tomography may be a safe alternative approach in these low-risk patients. However, the Alvarado score itself was not a predictive factor of nondiagnostic US. The absence of migratory pain, absence of leukocytosis, and low pain score were the independent predictors of nondiagnostic appendiceal US.

Multi-detector computed tomography in traumatic abdominal lesions: value and radiation control

Background, The context

A prospective study was conducted involving 81 patients (mean age, 20.79 years) with abdominal trauma who underwent ultrasonography and post-contrast CT on MDCT scanner. The total DLP for each patient was reviewed, and the effective dose was calculated. Purpose of the study to: explore the role of MDCT in assessing traumatic abdominal lesions, demonstrate radiation dose delivered by MDCT, and describe specific CT technical features to minimize radiation.

Results

The spleen was the most commonly injured organ (49.4%) followed by liver (39.5%) and kidney (24.7%). Pancreatic injury occurred in seven patients, whereas only two patients had intestinal injuries. One patient had adrenal injury. Minimal, mild and moderate free intra-peritoneal fluid collection was detected in 21 (25.9%), 47 (58%) and 10 (12.3%) patients, respectively. Only three (3.7%) patients had no collection. One patient had active uncontrolled bleeding and died. Radiation dose was below the detrimental level (calculated effective dose), with optimal image quality.

Conclusions

MDCT is sensitive to all types of traumatic abdominal lesions. Not only in determining the injury, but also in its grading. MDCT has affected the treatment directions, spotting a focus on conservative treatment by raising the diagnostic confidence. FAST cannot be the sole imaging modality. The individual radiation risk is small but real. Advancements in medical imaging reduce radiation risk.

Local Diagnostic Reference Levels for Paediatric Head CT Procedures

Background.

Patients, especially children, are exposed to substantially high doses of ionising radiation during computed tomography (CT) procedures. Children are several times more susceptible to ionising radiation than adults. Diagnostic reference levels (DRLs) are an important tool for monitoring and optimising patient radiation exposure from radiological procedures. The aim of this study is to estimate the ionising radiation exposure doses and set local DRLs for head CT examinations according to age and to compare local DRLs with national and European DRLs and with literature data in other countries.

Materials and methods.

Scan parameters of single-phase head CT examinations were collected. Patients were grouped by age in the following intervals: <1, 1−5, 5−10, 10−15 and 15−18 years. Local age-based DRLs set as the 3^rd quartile of the median dose-length product (DLP) were calculated. Literature analysis was performed on PubMed search engine on inclusion criteria: publication date 2015–2020, used keywords paediatric computed tomography, paediatric CT, diagnostic reference levels (DRLs). The 23 articles discussing paediatric DRLs were further analysed.

Results.

Data was collected from 194 paediatric head CT examinations performed in 2019. The median DLP values for head CT were 144.3, 233.7, 246.4, 288.9, 315.5 for <1, 1−5, 5−10, 10−15 and 15−18 years old groups. Estimated local DRLs for head CT examinations are 170, 300, 310, 320, 360 mGy*cm for <1, 1−5, 5−10, 10−15 and 15−18 years age groups respectively and 130, 210, 275, 320 mGy*cm for 0−3 months, 3 months−1 year, 1−6 years and ≥ 6 years age groups respectively.

Conclusions.

Results of this study showed that settled new local DRLs of head CT examinations were 2–4 times lower than national DRLs and about 2 times lower than European DRLs. Moreover, the study indicated that paediatric head CT doses are significantly lower in comparison with those indicated in the majority of published data from other hospitals over the last 6 years. Patient dose assessment and local DRLs establishment plays important role in future exposure optimisation.

Guidelines for reasonable and appropriate care in the emergency department (GRACE): Recurrent, low-risk chest pain in the emergency department

This first Guideline for Reasonable and Appropriate Care in the Emergency Department (GRACE-1) from the Society for Academic Emergency Medicine is on the topic: Recurrent, Low-risk Chest Pain in the Emergency Department. The multidisciplinary guideline panel used The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the certainty of evidence and strength of recommendations regarding eight priority questions for adult patients with recurrent, low-risk chest pain and have derived the following evidence based recommendations: (1) for those >3 h chest pain duration we suggest a single, high-sensitivity troponin below a validated threshold to reasonably exclude acute coronary syndrome (ACS) within 30 days; (2) for those with a normal stress test within the previous 12 months, we do not recommend repeat routine stress testing as a means to decrease rates of major adverse cardiac events at 30 days; (3) insufficient evidence to recommend hospitalization (either standard inpatient admission or observation stay) versus discharge as a strategy to mitigate major adverse cardiac events within 30 days; (4) for those with non-obstructive (<50% stenosis) coronary artery disease (CAD) on prior angiography within 5 years, we suggest referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation; (5) for those with no occlusive CAD (0% stenosis) on prior angiography within 5 years, we recommend referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation; (6) for those with a prior coronary computed tomographic angiography within the past 2 years with no coronary stenosis, we suggest no further diagnostic testing other than a single, normal high-sensitivity troponin below a validated threshold to exclude ACS within that 2 year time frame; (7) we suggest the use of depression and anxiety screening tools as these might have an effect on healthcare use and return emergency department (ED) visits; and (8) we suggest referral for anxiety or depression management, as this might have an impact on healthcare use and return ED visits.

Mixed reality models based on low-dose computed tomography technology in nephron-sparing surgery are better than models based on normal-dose computed tomography

Background

Nephron-sparing surgery has been widely applied in the treatment of renal tumors. Previous studies have confirmed the advantages of mixed reality technology in surgery. The study aimed to explore the optimization of mixed reality technology and its application value in nephron-sparing surgery.

Methods

In this prospective study of 150 patients with complex renal tumors (RENAL nephrometry score ≥7) who underwent nephron-sparing surgery, patients were randomly divided into Group A (the normal-dose mixed reality group, n=50), Group B (the low-dose mixed reality group, n=50), and Group C (the traditional computed tomography image group, n=50). Group A and Group C received the normal-dose computed tomography scan protocol: 120 kVp, 400 mA, and 350 mgI/mL, while Group B received the low-dose computed tomography scan protocol: 80 kVp, automatic tube current modulation, and 320 mgI/mL. All computed tomography data were transmitted to a three-dimensional visualization workstation and underwent modeling and mixed reality imaging. Two senior surgeons evaluated mixed reality quality. Objective indexes and perioperative indexes were calculated and compared.

Results

Compared with Group A, the radiation effective dose in Group B was decreased by 39.6%. The subjective scores of mixed reality quality in Group B were significantly higher than those of Group A (Z=-4.186, P<0.001). The inter-observer agreement between the two senior surgeons in mixed reality quality was excellent (K=0.840, P<0.001). The perioperative indexes showed that the mixed reality groups were significantly different from the computed tomography image group (all P<0.017). More cases underwent nephron-sparing surgery in the mixed reality groups than in the computed tomography image group (P<0.0017).

Conclusions

Low-dose computed tomography technology can be effectively applied to mixed reality optimization, reducing the effective dose and improving mixed reality quality. Optimized mixed reality can significantly increase the cases of successful nephron-sparing surgery and improve perioperative indexes.

Evaluation of the lifetime brain/central nervous system cancer risk associated with childhood head CT scanning in Japan

The use of computed tomography (CT) scanning has increased worldwide over the decades, and Japan is one of the leading countries in annual frequency of diagnostic CT. Although benefits of CT scan are undisputable, concerns have been raised about potential health effects of ionizing radiation exposure from CT, particularly among children who are likely more susceptible to radiation than adults. Our study aims to evaluate the cumulated lifetime risk of the brain/central nervous system (CNS) cancer due to head CT examinations performed on Japanese children at age 0 to 10 years in 2012, 2015 and 2018. The frequency and dose distribution of head CT examinations were estimated based on information from recent national statistics and nationwide surveys. The lifetime risk attributable to exposure was calculated by applying risk models based on the study of Japanese atomic-bomb survivors. In contrast to the overall increasing trend, the frequency of childhood CT, especially at age < 5, was decreasing, reflecting a growing awareness for efforts to reduce childhood CT exposure over the past decade. In 2018, 138 532 head CT examinations were performed at age 0 to 10, which would consequently induce a lifetime excess of 22 cases (1 per 6300 scans) of brain/CNS cancers, accounting for 5% of the total cases. More excess cases were estimated among men than among women, and excess cases could emerge at relatively young ages. These results would have useful implications as scientific basis for future large-scale epidemiological studies and also as quantitative evidence to justify the benefits of CT vs risks in Japan.

Risk trade-off analysis of returning home and radiation exposure after a nuclear disaster using a happy life expectancy indicator

It is crucial to evaluate ethical issues regarding evacuation orders, especially after a nuclear disaster. After the Fukushima accident in 2011, the Japanese government ordered the affected people to evacuate. The evacuation orders have now been lifted in many areas. A risk trade-off analysis between benefits and risk associated with returning home would help in evaluating the justification for the lifting of the evacuation order in the aftermath of a nuclear disaster. Here, we performed a risk trade-off analysis among people returning home after the lifting of an evacuation order between an increase in emotional happiness (positive effect) and loss of life expectancy due to additional radiation exposure (negative effect), using a happy life expectancy (HpLE) indicator. Emotional happiness was estimated using questionnaires distributed among the affected people who lived in municipalities where evacuation orders were lifted. Loss of life expectancy was estimated under a scenario that returnees received 20 mSv in the year of return and subsequent radiation exposure. Increase in emotional happiness due to returning home was ~1-2 orders of magnitude higher among women aged 20, 40 and 65 years than the loss of life expectancy due to additional radiation exposure. This finding has implications for the justification for the lifting of evacuation orders.

Cochlear implantation in children without preoperative computed tomography diagnostics. Analysis of procedure and rate of complications

INTRODUCTION

To evaluate the safety in cochlear implantation without preoperative computed tomography diagnostics, which was implemented into the protocol of cochlear implantation in 2013, since in the year before, new evidence concerning the risks of ionizing radiation especially in children arose.

METHODS

In this retrospective data analysis 89 children under 36 months, which were cochlear implanted from 2008 until 2018 at a tertiary referral centre with a large cochlear implant program were analysed. Fortyfour of the children were implanted before the date of change in 2013 and 45 in the following years up to now. The data about the operative procedures, the postoperative care and the complication rate before and after implementation of the new protocol were compared.

RESULTS

Before the date of change in 2013, 100% of patients received preoperative CT diagnostics, in the following years 13.3%. No difference in the duration of surgery, the procedure related and the late complications between the two groups was identified.

CONCLUSION

Cochlear implantation in very young children under the age of 36 months without preoperative radiological diagnostics by CT scan of the temporal bone is a safe procedure without additional risks for the patients.

ORGAN EQUIVALENT DOSE AND LIFETIME ATTRIBUTABLE RISK OF CANCER INCIDENCE AND MORTALITY ASSOCIATED WITH CARDIAC CT ANGIOGRAPHY

The aim of this study is the calculation of equivalent organ dose and estimation of lifetime attributable risk (LAR) of cancer incidence and mortality related to cardiac computed tomography angiography (CCTA) because the use of CT angiography as a noninvasive diagnostic method has increased. The organ dose has been calculated by ImPACT software based on the volumetric CT dose index (CTDIvol), and LAR of cancer risk incidence and mortality from CCTA has estimated according to the BEIR VII report. The median value of the effective dose was 13.78 ± 6.88 mSv for both genders. In all scanners, the highest median value for LAR of cancer incidence in males and females for lung cancer was 44.20 and 109.17 per 100 000, respectively. And in infants was 5.89 and 12 for lung cancer in males and breast cancer in females, respectively. Also, the median value of LAR of all cancer incidence from single CCTA in adult patients for males and females was 122 and 238 cases, respectively. Maximum LAR of cancer mortality in adults for lung cancer was 40.28 and 91.84 and in pediatrics was 5.69 and 8.50 in males and females, respectively. Despite many benefits of CTA in the heart disease evaluation, according to a high radiation dose in CCTA, to reduce the cancer risk: CCTA should be used cautiously, especially for pediatric and females.

Deep learning-based attenuation correction in the absence of structural information for whole-body positron emission tomography imaging

Deriving accurate structural maps for attenuation correction (AC) of whole-body positron emission tomography (PET) remains challenging. Common problems include truncation, inter-scan motion, and erroneous transformation of structural voxel-intensities to PET µ-map values (e.g. modality artifacts, implanted devices, or contrast agents). This work presents a deep learning-based attenuation correction (DL-AC) method to generate attenuation corrected PET (AC PET) from non-attenuation corrected PET (NAC PET) images for whole-body PET imaging, without the use of structural information. 3D patch-based cycle-consistent generative adversarial networks (CycleGAN) is introduced to include NAC-PET-to-AC-PET mapping and inverse mapping from AC PET to NAC PET, which constrains NAC-PET-to-AC-PET mapping to be closer to one-to-one mapping. Since NAC PET images share similar anatomical structures to the AC PET image but lack contrast information, residual blocks, which aim to learn the differences between NAC PET and AC PET, are used to construct generators of CycleGAN. After training, patches from NAC PET images were fed into NAC-PET-to-AC-PET mapping to generate DL-AC PET patches. DL-AC PET image was then reconstructed through patch fusion. We conducted a retrospective study on 55 datasets of whole-body PET/CT scans to evaluate the proposed method. In comparing DL-AC PET with original AC PET, average mean error (ME) and normalized mean square error (NMSE) of the whole-body were 0.62%  ±  1.26% and 0.72%  ±  0.34%. The average intensity changes measured on sequential PET images with AC and DL-AC on both normal tissues and lesions differ less than 3%. There was no significant difference of the intensity changes between AC and DL-AC PET, which demonstrate DL-AC PET images generated by the proposed DL-AC method can reach a same level to that of original AC PET images. The method demonstrates excellent quantification accuracy and reliability and is applicable to PET data collected on a single PET scanner or hybrid platform with computed tomography (PET/CT) or magnetic resonance imaging (PET/MRI).

A Scalable Database of Organ Doses for Common Diagnostic Fluoroscopy Procedures of Children: Procedures of Historical Practice for Use in Radiation Epidemiology Studies

Assessment of health effects from low-dose radiation exposures in patients undergoing diagnostic imaging is an active area of research. High-quality dosimetry information pertaining to these medical exposures is generally not readily available to clinicians or epidemiologists studying radiation-related health risks. The purpose of this study was to provide methods for organ dose estimation in pediatric patients undergoing four common diagnostic fluoroscopy procedures: the upper gastrointestinal (UGI) series, the lower gastrointestinal (LGI) series, the voiding cystourethrogram (VCUG) and the modified barium swallow (MBS). Abstracted X-ray film data and physician interviews were combined to generate procedure outlines detailing X-ray beam projections, imaged anatomy, length of X-ray exposure, and presence and amount of contrast within imaged anatomy. Monte Carlo radiation transport simulations were completed for each of the four diagnostic fluoroscopy procedures across the 162-member (87 males and 75 females) University of Florida/National Cancer Institute pediatric phantom library, which covers variations in both subject height and weight. Absorbed doses to 28 organs, including the active marrow and bone endosteum, were assigned for all 162 phantoms by procedure. Additionally, we provide dose coefficients (DCs) in a series of supplementary tables. The DCs give organ doses normalized to procedure-specific dose metrics, including: air kerma-area product (µGy/mGy · cm2), air kerma at the reference point (µGy/µGy), number of spot films (SF) (µGy/number of SFs) and total fluoroscopy time (µGy/s). Organs accumulating the highest absorbed doses per procedure were as follows: kidneys between 0.9-25.4 mGy, 1.1-16.6 mGy and 1.1-9.7 mGy for the UGI, LGI and VCUG procedures, respectively, and salivary glands between 0.2-3.7 mGy for the MBS procedure. Average values of detriment-weighted dose, a phantom-specific surrogate for the effective dose based on ICRP Publication 103 tissue-weighting factors, were 0.98 mSv, 1.16 mSv, 0.83 mSv and 0.15 mSv for the UGI, LGI, VCUG and MBS procedures, respectively. Scalable database of organ dose coefficients by patient sex, height and weight, and by procedure exposure time, reference point air kerma, kerma-area product or number of spot films, allows clinicians and researchers to compute organ absorbed doses based on their institution-specific and patient-specific dose metrics. In addition to informing on patient dosimetry, this work has the potential to facilitate exposure assessments in epidemiological studies designed to investigate radiation-related risks.

Imaging in craniosynostosis: when and what?

PURPOSE

Currently, the interest on craniosynostosis in the clinical practice is raised by their increased frequency and their genetic implications other than by the still existing search of less invasive surgical techniques. These reasons, together with the problem of legal issues, make the need of a definite diagnosis for a crucial problem, even in single-suture craniosynostosis (SSC). Although the diagnosis of craniosynostosis is primarily the result of physical examination, craniometrics measuring, and observation of the skull deformity, the radiological assessment currently plays an important role in the confirmation of the diagnosis, the surgical planning, and even the postoperative follow-up. On the other hand, in infants, the use of radiation or the need of sedation/anesthesia raises the problem to reduce them to minimum to preserve such a delicate category of patient from their adverse effects.

METHODS, RESULTS AND CONCLUSIONS

This review aims at summarizing the state of the art of the role of radiology in craniosynostosis, mainly focusing on indications and techniques, to provide an update not only to pediatric neurosurgeons or maxillofacial surgeons but also to all the other specialists involved in their management, like neonatologists, pediatricians, clinical geneticists, and pediatric neurologists.

Zero Fluoroscopy During Ablation of Right-Sided Supraventricular Tachycardia Substrates in a Pediatric Population - Initial Experience in Taiwan

Background

Zero fluoroscopy during ablation of arrhythmias has been introduced to reduce radiation exposure. However, the safety, feasibility and efficacy of the technique in pediatric populations have yet to be delineated.

Objectives

To investigate the safety, feasibility and effectiveness of zero fluoroscopic-guided transcatheter ablation of right-sided supraventricular tachycardia substrates in a pediatric population.

Methods

Patients < 20 years of age who received ablation of right-sided accessory pathway-mediated arrhythmia and atrioventricular nodal reentrant tachycardia at our hospital between January 2014 and July 2018 were enrolled, and their medical records were reviewed. Patients undergoing ablations with conventional fluoroscopic guidance were enrolled as the control group, and those undergoing ablations with zero fluoroscopic guidance were enrolled as the study group. Repaired or complex congenital heart disease patients were excluded.

Results

One hundred and two patients (55 male; 47 female) received a total of 109 ablation procedures: 68 procedures in the control group and 41 in the study group. The mean procedure duration was 104.7 ± 65.1 minutes in the control group and 98.6 ± 57.6 minutes in the study group (p = 0.62). The mean fluoroscopy time was 30.9 ± 23.9 minutes in the control group, while all procedures in the study group were performed without fluoroscopy (p < 0.001). In subgroup analysis, the results were similar. Acute procedural success rates were high in both groups (98.5% vs. 97.6%, p = 1.0). The recurrence rate was 11.5% (7/61) in the control group and 7.5% (3/40) in the study group (p = 0.78) at mid-term follow-up.

Conclusions

Using the zero fluoroscopy technique during pediatric ablation procedures for right-sided supraventricular tachycardia substrates is safe and significantly reduces radiation exposure.

Patient Safety Analysis in Radiation Burden of Head Computed Tomography Imaging in 1185 Neurosurgical Inpatients

OBJECTIVE

We performed a retrospective analysis in a cohort of 1185 patients at our institution who were identified as undergoing ≥1 head computed tomography (CT) examinations during their inpatient stay on the neurosurgery service, to quantify the number, type, and associated radiation burden of head CT procedures performed by the neurosurgery service.

METHODS

CT procedure records and radiology reports were obtained via database search and directly validated against records retrieved from manual chart review. Next, dosimetry data from the head CT procedures were extracted via automated text mining of electronic radiology reports.

RESULTS

Among 4510 identified adult head CT procedures, 88% were standard head CT examinations. A total of 3.65 ± 3.60 head CT scans were performed during an average adult admission. The most common primary diagnoses were neoplasms, trauma, and other hemorrhage. The median cumulative effective dose per admission was 5.66 mSv (range, 1.06-84.5 mSv; mean, 8.56 ± 8.95 mSv). The median cumulative effective dose per patient was 6.4 mSv (range, 1.1-127 mSv; mean, 9.26 ± 10.0 mSv).

CONCLUSIONS

The median cumulative radiation burden from head CT imaging in our cohort equates approximately to a single chest CT scan, well within accepted limits for safe CT imaging in adults. Refined methods are needed to characterize the safety profile of the few pediatric patients identified in our study.

One-pot synthesis of acid-induced in situ aggregating theranostic gold nanoparticles with enhanced retention in tumor cells

In this work, we took advantage of a one-pot reaction to prepare tumor-targeting nanoparticles (Au@T), which could respond to the intracellular acidic environment and form aggregates to enhance the retention effect of nanoparticles in tumor cells, for tumor dual-mode diagnose and photothermal therapy.

Centers for Disease Control and Prevention Guideline on the Diagnosis and Management of Mild Traumatic Brain Injury Among Children

Importance

Mild traumatic brain injury (mTBI), or concussion, in children is a rapidly growing public health concern because epidemiologic data indicate a marked increase in the number of emergency department visits for mTBI over the past decade. However, no evidence-based clinical guidelines have been developed to date for diagnosing and managing pediatric mTBI in the United States.

Objective

To provide a guideline based on a previous systematic review of the literature to obtain and assess evidence toward developing clinical recommendations for health care professionals related to the diagnosis, prognosis, and management/treatment of pediatric mTBI.

Evidence Review

The Centers for Disease Control and Prevention (CDC) National Center for Injury Prevention and Control Board of Scientific Counselors, a federal advisory committee, established the Pediatric Mild Traumatic Brain Injury Guideline Workgroup. The workgroup drafted recommendations based on the evidence that was obtained and assessed within the systematic review, as well as related evidence, scientific principles, and expert inference. This information includes selected studies published since the evidence review was conducted that were deemed by the workgroup to be relevant to the recommendations. The dates of the initial literature search were January 1, 1990, to November 30, 2012, and the dates of the updated literature search were December 1, 2012, to July 31, 2015.

Findings

The CDC guideline includes 19 sets of recommendations on the diagnosis, prognosis, and management/treatment of pediatric mTBI that were assigned a level of obligation (ie, must, should, or may) based on confidence in the evidence. Recommendations address imaging, symptom scales, cognitive testing, and standardized assessment for diagnosis; history and risk factor assessment, monitoring, and counseling for prognosis; and patient/family education, rest, support, return to school, and symptom management for treatment.

Conclusions and Relevance

This guideline identifies the best practices for mTBI based on the current evidence; updates should be made as the body of evidence grows. In addition to the development of the guideline, CDC has created user-friendly guideline implementation materials that are concise and actionable. Evaluation of the guideline and implementation materials is crucial in understanding the influence of the recommendations.

Subtle excess in lifetime cancer risk related to CT scanning in Spanish young people

BACKGROUND

CT scan is a life-saving medical diagnostic tool, entailing higher levels of ionising radiation exposure than conventional radiography, which may result in an increase in cancer risk, particularly in children. Information about the use and potential health effects of CT scan imaging among young people in Spain is scarce.

OBJECTIVE

This paper aims to estimate the number of radiation-related cancer cases which can be expected due to the use of CT scanning in Spanish children and young adults in a single year (2013).

METHODS

The 2013 distribution of number and types of CT scans performed in young people was obtained for Catalonia and extrapolated to the whole Spain. Organ doses were estimated based on the technical characteristics of 17,406 CT examinations extracted from radiology records. Age and sex-specific data on cancer incidence and life tables were obtained for the Spanish population. Age and sex-specific risk models developed by the Committee on Health Risks of Exposure to Low Levels of Ionizing Radiations (BEIR VII) and Berrington de Gonzalez were used, together, with the dose estimates to derive the lifetime attributable risks of cancer in Spain due to one year of CT scanning and project the number of future cancer cases to be expected.

RESULTS

In 2013, 105,802 CT scans were estimated to have been performed in people younger than age 21. It was estimated that a total of 168.6 cancer cases (95% CrI: 30.1-421.1) will arise over life due to the ionising radiation exposure received during these CTs. Lifetime attributable risks per 100,000 exposed patients were highest for breast and lung cancer. The largest proportion of CTs was to the head and neck and hence the highest numbers of projected cancer cases were of thyroid and oral cavity/pharynx.

CONCLUSIONS

Despite the undeniable medical effectiveness of CT scans, this risk assessment suggests a small excess in cancer cases which underlines the need for justification and optimisation in paediatric scanning. Given the intrinsic uncertainties of these risk projection exercises, care should be taken when interpreting the predicted risks.

Indication of whole body computed tomography in pediatric polytrauma patients-Diagnostic potential of the Glasgow Coma Scale, the mechanism of injury and clinical examination

OBJECTIVE

To evaluate the diagnostic potential of the Glasgow Coma Scale (GCS), the mechanism of injury (MOI) and clinical examination (CE) for the indication of whole body computed tomography (WBCT) in pediatric polytrauma patients.

MATERIALS & METHODS

100 pediatric polytrauma patients with WBCT were analysed in terms of age, gender, (MOI), GCS, detected injury, FAST, CE and Injury Severity Score (ISS). Correlations between all clinical variables and patient groups with (p+) and without (p-) injury were assessed.

RESULTS

Mean age was 9.13 ± 4.4 years (28% female patients). Injury was detected in 71% of the patients, most commonly of the head (43%). There was no significant correlation between type or severity of MOI and ISS (p > 0.1). None of the clinical variables had a significant predictive effect on p+. The optimum discrimination threshold of GCS was at 12.5 relating to craniocerebral injuries. Severity of MOI and FAST showed best predictive effects on thoracic and abdominal pathologies, respectively, but with only low sensitivities (<20%).

CONCLUSION

There is no clinical variable, which can be used as sole indication for WBCT in pediatric polytrauma patients. GCS had a significant predictive value for craniocerbral injuries and CCT is recommended at GCS ≤ 13.

Importance of risk comparison for individual and societal decision-making after the Fukushima disaster

Risk comparison is essential for effective societal and individual decision-making. After the Fukushima disaster, studies compared radiation and other disaster-related risks to determine the effective prioritizing of measures for response. Evaluating the value of risk comparison information can enable effective risk communication. In this review, the value of risk comparison after the Fukushima disaster for societal and individual decision-making is discussed while clarifying the concept of radiation risk assessment at low doses. The objectives of radiation risk assessment are explained within a regulatory science framework, including the historical adoption of the linear non-threshold theory. An example of risk comparison (i.e. radiation risk versus evacuation-related risk in nursing homes) is used to discuss the prioritization of pre-disaster measures. The effective communication of risk information by authorities is discussed with respect to group-based and face-to-face approaches. Furthermore, future perspectives regarding radiation risk comparisons are discussed.

Age-dependent differences in DNA damage after in vitro CT exposure

PURPOSE

Age dependent radiation sensitivity for DNA damage after in vitro blood exposure by computer tomography (CT) was investigated.

MATERIALS AND METHODS

Radiation biomarkers (dicentrics and gammaH2AX) in blood samples of newborns, children under five years and adults after sham exposure (0 mGy), low-dose (41 mGy) and high-dose (978 mGy) in vitro CT exposure were analyzed.

RESULTS

Significantly higher levels of dicentric induction were found for the single and combined newborns/children group compared to adults, by a factor of 1.48 (95% CI 1.30-1.68), after exposure to 978 mGy. Although a significant dose response for damage induction and dose-dependent repair was found, the gammaH2AX assay did not show an age-dependent increase in DNA damage in newborns/children compared to adults. This was the case for the gammaH2AX levels after repair time intervals of 30 minutes and 24 hours, after correcting for the underlying background damage. For the low dose of 41 mGy, the power of the dicentric assay was also not sufficient to detect an age-dependent effect in the sample size investigated.

CONCLUSION

A 1.5-fold increased level of dicentric aberrations is detected in newborns and children under five years after 1 Gy radiation exposure.

Is Low-Dose Radiation Exposure a Risk Factor for Atherosclerotic Disease?

Nontargeted late effects of radiation include an increased risk of cardiovascular disease, although this is still debatable in the context of low-dose radiation. Tinea capitis patients treated in childhood with X rays to induce scalp epilation received a low dose of radiation to their carotids. To better clarify this issue, we evaluated carotid atherosclerosis in a cohort of such patients treated in 1950-1963 in Portugal. A group of 454 individuals randomly chosen from previously observed Portuguese tinea capitis patients and a control group mainly composed of their spouses (n = 280) were enrolled. Cardiovascular risk factors such as waist circumference, body mass index, blood pressure and tobacco consumption, as well as biochemical measurements were obtained. Ultrasound imaging of carotid arteries for intima media thickness and stenosis evaluation were performed according to a standardized protocol. In comparison to the control group, the irradiated cohort members were significantly older, more frequently never smokers, hypertensive, and presented higher glycated hemoglobin and alkaline phosphatase levels. In addition, the irradiated cohort showed a higher frequency of carotid stenosis ≥30% than the nonirradiated group (13.9% vs. 10.7%), although this was not significant ( P = 0.20). Stenosis was ≥50% in 2.9% of the irradiated group and 0.4% of the nonirradiated group ( P = 0.02). Likewise, the frequency of intima media thickness ≥1 mm was significantly higher in the irradiated group (16.8% vs. 10.7%; P = 0.02). Multivariate analysis, including other cardiovascular risk factors, showed that exposure to low-dose radiation increased the risk of carotid stenosis by ≥50% [odds ratio (OR) = 8.85; P = 0.04] and intima media thickness by ≥1 mm (OR = 1.82; P = 0.02). These findings confirm that low-dose exposure is a risk factor of carotid atherosclerotic disease.

New "loss of happy life expectancy" indicator and its use in risk comparison after Fukushima disaster

To assess the effects of policy measures taken to ensure health and promote well-being, we developed a novel indicator, "loss of happy life expectancy" (LHpLE), under the concept that an objective of life is maximization of lifelong happiness, by using objective survival probabilities and a simple question regarding emotional happiness: "Did you experience a feeling of happiness yesterday [yes/no]?" We measured the emotional happiness of 4990 Japanese respondents through a questionnaire. We then used LHpLE to compare risks after the 2011 Fukushima disaster. LHpLE due to psychological distress was estimated from a decline of emotional happiness, whereas that due to radiation exposure was assessed from shortened life expectancy caused by additional cancer mortality. LHpLE values due to psychological distress in evacuees were approximately 1 to >2 orders of magnitude higher than those due to cancer mortality caused by actual radiation exposure, highlighting the importance of measures to minimize distress following public health emergencies. LHpLE could be used for integrated risk comparison among different types of harms and therefore in government policy-making.

Long-term changes in computed tomography and ultrasound utilization in a pediatric emergency department

Objective

Many studies have proposed reducing unnecessary use of computed tomography (CT), and ongoing studies in pediatric populations are aiming to decrease radiation dosages whenever possible. We aimed to evaluate the long-term changes in the utilization patterns of CT and ultrasound (US) in pediatric emergency departments (PEDs).

Methods

This retrospective study reviewed the electronic medical data of patients who underwent CT and/or US in the PED of a tertiary referral hospital from 2000 to 2014. We compared the changes in utilization patterns of brain and abdominal CT scans in pediatric patients and analyzed changes in abdominal US utilization in the PED.

Results

During the study period, 196,371 patients visited the PED. A total of 12,996 brain and abdominal CT scans and 12,424 abdominal US were performed in the PED. Comparison of CT use in pediatric patients before and after 2007 showed statistically decreasing trends after 2007, expressed as the coefficient values of the differences in groups. The numbers of brain and abdominal CT scans showed a significant decreasing trend in children, except for abdominal CT in adolescents. The abdominal US/CT ratio in the PED showed a statistically significant increase (2.68; 95% confidence interval, 1.87 to 3.49) except for the adolescent group (5.82; 95% confidence interval, -2.06 to 13.69).

Conclusion

Overall, CT use in pediatric patients has decreased since 2007. Pediatric US use has also shown a decreasing trend; however, the abdominal US/CT ratio in pediatric patients showed an increasing trend, except for adolescents.

Risk of Brain Tumor Induction from Pediatric Head CT Procedures: A Systematic Literature Review

Head computed tomography (CT) is instrumental for managing patients of all ages. However, its low dose radiation may pose a low but non-zero risk of tumor induction in pediatric patients. Here, we present a systematic literature review on the estimated incidence of brain tumor induction from head CT exams performed on children and adolescents. MEDLINE was searched using an electronic protocol and bibliographic searches to identify articles related to CT, cancer, and epidemiology or risk assessment. Sixteen studies that predicted or measured head CT-related neoplasm incidence or mortality were identified and reviewed. Epidemiological studies consistently cited increased tumor incidence in pediatric patients (ages 0–18) exposed to head CTs. Excess relative risk of new brain tumor averaged 1.29 (95% confidence interval, 0.66–1.93) for pediatric patients exposed to one or more head CTs. Tumor incidence increased with number of pediatric head CTs in a dose-dependent manner, with measurable excess incidence even after a single scan. Converging evidence from epidemiological studies supported a small excess risk of brain tumor incidence after even a single CT exam in pediatric patients. However, refined epidemiological methods are needed to control for confounding variables that may contribute to reverse causation, such as patients with pre-existing cancer or cancer susceptibility. CT remains an invaluable technology that should be utilized so long as there is clinical indication for the study and the radiation dose is as small as reasonably achievable.

Radiation Dose Comparison Between 70 kVp and 100 kVp With Spectral Beam Shaping for Non-Contrast-Enhanced Pediatric Chest Computed Tomography: A Prospective Randomized Controlled Study

OBJECTIVE

The aim of this prospective randomized controlled study was to compare 2 techniques for radiation dose reduction in non-contrast-enhanced pediatric chest computed tomography (CT): low peak kilovoltage imaging at 70 kVp and spectral beam shaping at 100 kVp using a dedicated tin filter (100-kVp Sn).

MATERIALS AND METHODS

All chest CT examinations were performed on a third-generation dual-source CT system (SOMATOM Force; Siemens Healthineers, Germany). Fifty children (mean age, 6.8 ± 5.1 years) were examined using the 100-kVp Sn protocol, whereas 25 children received the 70-kVp protocol (mean age, 5.7 ± 5.2 years; 2:1 randomization scheme). Radiation metrics and organ doses were compared between acquisition techniques using commercially available radiation dose analysis software (Radimetrics Inc, Bayer AG, Toronto, Ontario, Canada). Objective image quality, expressed by signal-to-noise ratio and subjective image quality based on a 4-point scale (1, best; 4, worst image quality), were compared.

RESULTS

Volume CT dose index and size-specific dose estimate were significantly lower in the 100-kVp Sn group compared with the 70-kVp group (0.19 ± 0.12 mGy vs 0.81 ± 0.70 mGy and 0.34 ± 0.13 mGy vs 1.48 ± 1.11 mGy; P < 0.0001 for both). Accordingly, mean effective dose was significantly lower for the 100-kVp Sn examinations (0.21 ± 0.10 mSv) compared with the 70-kVp examinations (0.83 ± 0.49 mSv; P < 0.0001). Calculated organ doses were also significantly lower using the 100-kVp Sn protocol when compared with the 70-kVp protocol; for example, breast dose was reduced by a factor of 4.3. Signal-to-noise ratio was slightly superior for 70-kVp images while lung image quality of the 100-kVp Sn protocol was preferred in subjective analysis (P = 0.0004).

CONCLUSIONS

Pediatric chest CT performed at 100 kVp with an additional tin filter for spectral shaping significantly reduces radiation dose when compared with low peak kilovoltage imaging at 70 kVp and therefore should be preferred in non-contrast-enhanced pediatric chest CT examinations, particularly (given the improved subjective image quality) when the main focus is evaluation of the lung parenchyma.

Comparison of Noninvasive High-Intensity Focused Ultrasound with Radiofrequency Ablation of Osteoid Osteoma

OBJECTIVE

To evaluate clinical feasibility and safety of magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) treatment of symptomatic osteoid osteoma and to compare clinical response with standard of care treatment.

STUDY DESIGN

Nine subjects with radiologically confirmed, symptomatic osteoid osteoma were treated with MR-HIFU in an institutional review board-approved clinical trial. Treatment feasibility and safety were assessed. Clinical response was evaluated in terms of analgesic requirement, visual analog scale pain score, and sleep quality. Anesthesia, procedure, and recovery times were recorded. This MR-HIFU group was compared with a historical control group of 9 consecutive patients treated with radiofrequency ablation.

RESULTS

Nine subjects (7 male, 2 female; 16 ± 6 years) were treated with MR-HIFU without technical difficulties or any serious adverse events. There was significant decrease in their median pain scores 4 weeks within treatment (6 vs 0, P < .01). Total pain resolution and cessation of analgesics were achieved in 8 of 9 patients after 4 weeks. In the radiofrequency ablation group, 9 patients (8 male, 1 female; 10 ± 6 years) were treated in routine clinical practice. All 9 demonstrated complete pain resolution and cessation of medications by 4 weeks with a significant decrease in median pain scores (9 vs 0, P < .001). One developed a second-degree skin burn, but there were no other adverse events. Procedure times and treatment charges were comparable between the 2 groups.

CONCLUSION

This pilot study shows that MR-HIFU treatment of osteoid osteoma refractory to medical therapy is feasible and can be performed safely in pediatric patients. Clinical response is comparable with standard of care treatment but without any incisions or exposure to ionizing radiation.

TRIAL REGISTRATION

ClinicalTrials.govNCT02349971.

Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with USG and standard dose CT

OBJECTIVES

Computed tomography should be performed after careful consideration due to radiation hazard, which is why interest in low dose CT has increased recently in acute appendicitis. Previous studies have been performed in adult and adolescents populations, but no studies have reported on the efficacy of using low-dose CT in children younger than 10 years.

METHODS

Patients (n=475) younger than 10 years who were examined for acute appendicitis were recruited. Subjects were divided into three groups according to the examinations performed: low-dose CT, ultrasonography, and standard-dose CT. Subjects were categorized according to age and body mass index (BMI).

RESULTS

Low-dose CT was a contributive tool in diagnosing appendicitis, and it was an adequate method, when compared with ultrasonography and standard-dose CT in terms of sensitivity (95.5% vs. 95.0% and 94.5%, p=0.794), specificity (94.9% vs. 80.0% and 98.8%, p=0.024), positive-predictive value (96.4% vs. 92.7% and 97.2%, p=0.019), and negative-predictive value (93.7% vs. 85.7% and 91.3%, p=0.890). Low-dose CT accurately diagnosed patients with a perforated appendix. Acute appendicitis was effectively diagnosed using low-dose CT in both early and middle childhood. BMI did not influence the accuracy of detecting acute appendicitis on low-dose CT.

CONCLUSION

Low-dose CT is effective and accurate for diagnosing acute appendicitis in childhood, as well as in adolescents and young adults. Additionally, low-dose CT was relatively accurate, irrespective of age or BMI, for detecting acute appendicitis. Therefore, low-dose CT is recommended for assessing children with suspected acute appendicitis.

The future: surgical advances in MEN1 therapeutic approaches and management strategies

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary autosomal dominant disorder associated with numerous neuroendocrine tumors (NETs). Recent advances in the management of MEN1 have led to a decrease in mortality due to excess hormones; however, they have also led to an increase in mortality from malignancy, particularly NETs. The main challenges are to localize these tumors, to select those that need therapy because of the risk of aggressive behavior and to select the appropriate therapy associated with minimal morbidity. This must be applied to a hereditary disease with a high risk of recurrence. The overall aim of management in MEN1 is to ensure that the patient remains disease- and symptom-free for as long as possible and maintains a good quality of life. Herein, we review the changes that occurred in the last 20 years in the surgical management of MEN1-associated functional and non-functional pancreatico-duodenal NETs and thymic and bronchial NETs.

Operational and Dosimetric Aspects of Pediatric PET/CT

No consistent guidelines exist for the acquisition of a CT scan as part of pediatric PET/CT. Given that children may be more vulnerable to the effects of ionizing radiation, it is necessary to develop methods that provide diagnostic-quality imaging when needed, in the shortest time and with the lowest patient radiation exposure. This article describes the basics of CT dosimetry and PET/CT acquisition in children. We describe the variability in pediatric PET/CT techniques, based on a survey of 19 PET/CT pediatric institutions in North America. The results of the survey demonstrated that, although most institutions used automatic tube current modulation, there remained a large variation of practice, on the order of a factor of 2-3, across sites, pointing to the need for guidelines. We introduce the approach developed at our institution for using a multiseries PET/CT acquisition technique that combines diagnostic-quality CT in the essential portion of the field of view and a low-dose technique to image the remainder of the body. This approach leads to a reduction in radiation dose to the patient while combining the PET and the diagnostic CT into a single acquisition. The standardization of pediatric PET/CT provides an opportunity for a reduction in the radiation dose to these patients while maintaining an appropriate level of diagnostic image quality.

Thyroid Cancer Following Childhood Low-Dose Radiation Exposure: A Pooled Analysis of Nine Cohorts

CONTEXT

The increased use of diagnostic and therapeutic procedures that involve radiation raises concerns about radiation effects, particularly in children and the radiosensitive thyroid gland.

OBJECTIVES

Evaluation of relative risk (RR) trends for thyroid radiation doses <0.2 gray (Gy); evidence of a threshold dose; and possible modifiers of the dose-response, e.g., sex, age at exposure, time since exposure.

DESIGN AND SETTING

Pooled data from nine cohort studies of childhood external radiation exposure and thyroid cancer with individualized dose estimates, ≥1000 irradiated subjects or ≥10 thyroid cancer cases, with data limited to individuals receiving doses <0.2 Gy.

PARTICIPANTS

Cohorts included the following: childhood cancer survivors (n = 2); children treated for benign diseases (n = 6); and children who survived the atomic bombings in Japan (n = 1). There were 252 cases and 2,588,559 person-years in irradiated individuals and 142 cases and 1,865,957 person-years in nonirradiated individuals.

INTERVENTION

There were no interventions.

MAIN OUTCOME MEASURE

Incident thyroid cancers.

RESULTS

For both <0.2 and <0.1 Gy, RRs increased with thyroid dose (P < 0.01), without significant departure from linearity (P = 0.77 and P = 0.66, respectively). Estimates of threshold dose ranged from 0.0 to 0.03 Gy, with an upper 95% confidence bound of 0.04 Gy. The increasing dose-response trend persisted >45 years after exposure, was greater at younger age at exposure and younger attained age, and was similar by sex and number of treatments.

CONCLUSIONS

Our analyses reaffirmed linearity of the dose response as the most plausible relationship for "as low as reasonably achievable" assessments for pediatric low-dose radiation-associated thyroid cancer risk.

Evaluation of an imaging protocol using ultrasound as the primary diagnostic modality in pediatric patients with superficial soft tissue infections of the face and neck

OBJECTIVE

To determine the clinical impact of an initiative to use ultrasound (US) as the primary diagnostic modality for children with superficial face and neck infections versus use of computed tomography (CT).

METHODS

Children with a diagnosis of lymphadenitis, face or neck abscess, or face and neck cellulitis were retrospectively evaluated by the otolaryngology service. Patients were separated into two groups based on implementation of a departmental initiative to use US as the primary diagnostic modality. The pre-implementation cohort consisted of patients treated prior to the initiative (2006-2009) and the current protocol cohort consisted of patients treated after the initiative was started (2010-2013). Demographics, use of US or CT, necessity of surgical intervention, and failure of medical management were compared.

RESULTS

Three hundred seventy three children were evaluated; 114 patients were included in the pre-implementation cohort and 259 patients were included in the current protocol cohort for comparison. Patients presenting during the current protocol period were more likely to undergo US (pre-implementation vs. current protocol, p-value) (12% vs. 49%, p < 0.0001) and less likely to undergo CT (66% vs. 41%, p < 0.0001) for their initial evaluation. There were no differences in the percentage of children who underwent prompt surgical drainage, prompt discharge without surgery, or trial inpatient observation. There were also no differences in the rate of treatment failure for patients undergoing prompt surgery or prompt discharge on antibiotics. For those patients who underwent repeat evaluation following trial medical management, US was used more frequently in the current protocol period (4% vs. 20%, p = 0.002) with no difference in CT use, selected treatment strategy, or treatment failure rates.

CONCLUSION

Increased use of US on initial evaluation of children with superficial face and neck infections resulted in decreased CT utilization, without negatively impacting outcome. Decreasing pediatric radiation exposure and potential long-term effects is of primary importance.

Projected cancer risks potentially related to past, current, and future practices in paediatric CT in the United Kingdom, 1990-2020

BACKGROUND

To project risks of developing cancer and the number of cases potentially induced by past, current, and future computed tomography (CT) scans performed in the United Kingdom in individuals aged <20 years.

METHODS

Organ doses were estimated from surveys of individual scan parameters and CT protocols used in the United Kingdom. Frequencies of scans were estimated from the NHS Diagnostic Imaging Dataset. Excess lifetime risks (ELRs) of radiation-related cancer were calculated as cumulative lifetime risks, accounting for survival probabilities, using the RadRAT risk assessment tool.

RESULTS

In 2000-2008, ELRs ranged from 0.3 to 1 per 1000 head scans and 1 to 5 per 1000 non-head scans. ELRs per scan were reduced by 50-70% in 2000-2008 compared with 1990-1995, subsequent to dose reduction over time. The 130 750 scans performed in 2015 in the United Kingdom were projected to induce 64 (90% uncertainty interval (UI): 38-113) future cancers. Current practices would lead to about 300 (90% UI: 230-680) future cancers induced by scans performed in 2016-2020.

CONCLUSIONS

Absolute excess risks from single exposures would be low compared with background risks, but even small increases in annual CT rates over the next years would substantially increase the number of potential subsequent cancers.

Childhood Leukemia and Primary Prevention

Leukemia is the most common pediatric cancer, affecting 3800 children per year in the United States. Its annual incidence has increased over the last decades, especially among Latinos. Although most children diagnosed with leukemia are now cured, many suffer long-term complications, and primary prevention efforts are urgently needed. The early onset of leukemia-usually before 5 years of age-and the presence at birth of "pre-leukemic" genetic signatures indicate that pre- and postnatal events are critical to the development of the disease. In contrast to most pediatric cancers, there is a growing body of literature-in the United States and internationally-that has implicated several environmental, infectious, and dietary risk factors in the etiology of childhood leukemia, mainly for acute lymphoblastic leukemia, the most common subtype. For example, exposures to pesticides, tobacco smoke, solvents, and traffic emissions have consistently demonstrated positive associations with the risk of developing childhood leukemia. In contrast, intake of vitamins and folate supplementation during the preconception period or pregnancy, breastfeeding, and exposure to routine childhood infections have been shown to reduce the risk of childhood leukemia. Some children may be especially vulnerable to these risk factors, as demonstrated by a disproportionate burden of childhood leukemia in the Latino population of California. The evidence supporting the associations between childhood leukemia and its risk factors-including pooled analyses from around the world and systematic reviews-is strong; however, the dissemination of this knowledge to clinicians has been limited. To protect children's health, it is prudent to initiate programs designed to alter exposure to well-established leukemia risk factors rather than to suspend judgment until no uncertainty remains. Primary prevention programs for childhood leukemia would also result in the significant co-benefits of reductions in other adverse health outcomes that are common in children, such as detriments to neurocognitive development.

Can clinical prediction tools predict the need for computed tomography in blunt abdominal? A systematic review

INTRODUCTION

Blunt abdominal trauma is a common reason for admission to the Emergency Department. Early detection of injuries is an important goal but is often not straightforward as physical examination alone is not a good predictor of serious injury. Computed tomography (CT) has become the primary method for assessing the stable trauma patient. It has high sensitivity and specificity but there remains concern regarding the long term consequences of high doses of radiation. Therefore an accurate and reliable method of assessing which patients are at higher risk of injury and hence require a CT would be clinically useful. We perform a systematic review to investigate the use of clinical prediction tools (CPTs) for the identification of abdominal injuries in patients suffering blunt trauma.

MATERIALS AND METHODS

A literature search was performed using Medline, Embase, The Cochrane Library and NHS Evidence up to August 2014. English language, prospective and retrospective studies were included if they derived, validated or assessed a CPT, aimed at identifying intra-abdominal injuries or the need for intervention to treat an intra-abdominal after blunt trauma. Methodological quality was assessed using a 14 point scale. Performance was assessed predominantly by sensitivity.

RESULTS

Seven relevant studies were identified. All studies were derivative studies and no CPT was validated in a separate study. There were large differences in the study design, composition of the CPTs, the outcomes analysed and the methodological quality of the included studies. Sensitivities ranged from 86 to 100%. The highest performing CPT had a lower limit of the 95% CI of 95.8% and was of high methodological quality (11 of 14). Had this rule been applied to the population then 25.1% of patients would have avoided a CT scan.

CONCLUSIONS

Seven CPTs were identified of varying designs and methodological quality. All demonstrate relatively high sensitivity with some achieving very high sensitivity whilst still managing to reduce the number of CTs performed by a significant amount. Further studies are required to validate the results obtained by the highest performing CPTs before any firm recommendation can be used regarding their use in routine clinical practice.

Comprehensive review on endonasal endoscopic sinus surgery

Endonasal endoscopic sinus surgery is the standard procedure for surgery of most paranasal sinus diseases. Appropriate frame conditions provided, the respective procedures are safe and successful. These prerequisites encompass appropriate technical equipment, anatomical oriented surgical technique, proper patient selection, and individually adapted extent of surgery. The range of endonasal sinus operations has dramatically increased during the last 20 years and reaches from partial uncinectomy to pansinus surgery with extended surgery of the frontal (Draf type III), maxillary (grade 3-4, medial maxillectomy, prelacrimal approach) and sphenoid sinus. In addition there are operations outside and beyond the paranasal sinuses. The development of surgical technique is still constantly evolving. This article gives a comprehensive review on the most recent state of the art in endoscopic sinus surgery according to the literature with the following aspects: principles and fundamentals, surgical techniques, indications, outcome, postoperative care, nasal packing and stents, technical equipment.

Follicular cell-derived thyroid cancer

Follicular cell-derived thyroid cancers are derived from the follicular cells in the thyroid gland, which secrete the iodine-containing thyroid hormones. Follicular cell-derived thyroid cancers can be classified into papillary thyroid cancer (80-85%), follicular thyroid cancer (10-15%), poorly differentiated thyroid cancer (<2%) and undifferentiated (anaplastic) thyroid cancer (<2%), and these have an excellent prognosis with the exception of undifferentiated thyroid cancer. The advent and expansion of advanced diagnostic techniques has driven and continues to drive the epidemic of occult papillary thyroid cancer, owing to overdiagnosis of clinically irrelevant nodules. This transformation of the thyroid cancer landscape at molecular and clinical levels calls for the modification of management strategies towards personalized medicine based on individual risk assessment to deliver the most effective but least aggressive treatment. In thyroid cancer surgery, for instance, injuries to structures outside the thyroid gland, such as the recurrent laryngeal nerve in 2-5% of surgeries or the parathyroid glands in 5-10% of surgeries, negatively affect quality of life more than loss of the expendable thyroid gland. Furthermore, the risks associated with radioiodine ablation may outweigh the risks of persistent or recurrent disease and disease-specific mortality. Improvement in the health-related quality of life of survivors of follicular cell-derived thyroid cancer, which is decreased despite the generally favourable outcome, hinges on early tumour detection and minimization of treatment-related sequelae. Future opportunities include more widespread adoption of molecular and clinical risk stratification and identification of actionable targets for individualized therapies.

Was the Risk from Nursing-Home Evacuation after the Fukushima Accident Higher than the Radiation Risk?

After the 2011 accident at the Fukushima Daiichi nuclear power plant, nursing-home residents and staff were evacuated voluntarily from damaged areas to avoid radiation exposure. Unfortunately, the evacuation resulted in increased mortalities among nursing home residents. We assessed the risk trade-off between evacuation and radiation for 191 residents and 184 staff at three nursing homes by using the same detriment indicator, namely loss of life expectancy (LLE), under four scenarios, i.e. "rapid evacuation (in accordance with the actual situation; i.e. evacuation on 22 March)," "deliberate evacuation (i.e. evacuation on 20 June)," "20-mSv exposure," and "100-mSv exposure." The LLE from evacuation-related mortality among nursing home residents was assessed with survival probability data from nursing homes in the city of Minamisoma and the city of Soma. The LLE from radiation mortality was calculated from the estimated age-specific mortality rates from leukemia and all solid cancers based on the additional effective doses and the survival probabilities. The total LLE of residents due to evacuation-related risks in rapid evacuation was 11,000 persons-d-much higher than the total LLEs of residents and staff due to radiation in the other scenarios (27, 1100, and 5800 persons-d for deliberate evacuation, 20 mSv-exposure, and 100 mSv-exposure, respectively). The latitude for reducing evacuation risks among nursing home residents is surprisingly large. Evacuation regulation and planning should therefore be well balanced with the trade-offs against radiation risks. This is the first quantitative assessment of the risk trade-off between radiation exposure and evacuation after a nuclear power plant accident.

Changes in radiological imaging frequencies in children before and after the accident at the Fukushima Daiichi Nuclear Power Plant in Fukushima Prefecture, Japan

PURPOSE

The accident at the Fukushima Daiichi Nuclear Power Plant has raised concerns about radiation exposure, including medical radiation exposure such as X-ray and CT, in residents of Fukushima.

MATERIALS AND METHODS

We compared the numbers and the ratio of outpatients less than 10 years old who underwent imaging examinations [e.g., CT, X-ray, MRI, ultrasonography (US), etc.] at Fukushima Medical University hospital in Fukushima, Japan before (April 1, 2008-March 31, 2011) and after (April 1, 2011-March 31, 2014) the accident.

RESULTS

The number of outpatients less than 10 years old decreased after the accident. The number of outpatients less than 10 years old who underwent CT and X-ray examinations also significantly decreased after the accident (p < 0.001, p < 0.01, respectively).

CONCLUSION

Our results suggest that the number of pediatric radiological examinations decreased after the accident in Fukushima. We should continue to communicate with patients and their families to ensure that they understand the risks and benefits of radiological imaging in order to overcome their concerns about the nuclear disaster.