ALARA: is there a cause for alarm? Reducing radiation risks from computed tomography scanning in children

Prevalence of malignancies among U.S. male patients with haemophilia: a review of the Haemophilia Surveillance System

The prevalence of malignancies in US male patients with haemophilia, with or without concomitant viral infections, remains unknown. To estimate the prevalence of malignancy in US male patients with haemophilia. We investigated the prevalence of malignancies among male patients with haemophilia using data from a six-state haemophilia surveillance project. Case patients with malignancies were identified using International Classification of Diseases, 9th Revision, Clinical Modification codes abstracted from hospital records and death certificates during the surveillance period. Cancer prevalence rates were calculated for each year during the surveillance and compared with age- and race-specific prevalence rates among the U.S. male population obtained from the Surveillance, Epidemiology and End Results (SEER) Program. A total of 7 cases of leukaemia, 23 cases of lymphoma and 56 classifiable solid malignancies were identified among 3510 case patients during a total of 15,330 annual data abstraction collections. The rates of leukaemia, lymphoma and liver cancer among case patients were significantly higher than the rates among U.S. males as judged by prevalence ratios of 3.1 [95% confidence interval (CI) = 1.4-7.0] and 2.9 (95% CI =1.8-4.6), respectively. In contrast, the prevalence ratio of prostate cancer was lower than expected at 0.49 (95% CI = 0.31-0.77). Overall the prevalence of most cancers among case patients was similar to that of the U.S. male population. However, patients with haemophilia who have unexplained symptoms should be evaluated for malignancy.

Antiscatter grid use in pediatric digital tomosynthesis imaging

The objective of this study was to assess the effect of antiscatter grid use on tomosynthesis image quality. We performed an observer study that rated the image quality of digital tomosynthesis scout radiographs and slice images of a Leeds TO.20 contrast‐detail test object embedded in acrylic with and without a grid. We considered 10, 15, 20 and 25 cm of acrylic to represent the wide range of patient thicknesses encountered in pediatric imaging. We also acquired and rated images without a grid at an increased patient dose. The readers counted the total number of visible details in each image as a measure of relative image quality. We observed that the antiscatter grid improves tomosynthesis image quality compared to the grid‐out case, which received image quality scores similar to grid‐in radiography. Our results suggest that, in order to achieve the best image quality in exchange for the increase in patient dose, it may often be appropriate to include an antiscatter grid for pediatric tomosynthesis imaging, particularly if the patient thickness is greater than 10 cm.

PACS number: 87.57.‐s

Biological effects and adaptive response from single and repeated computed tomography scans in reticulocytes and bone marrow of C57BL/6 mice

This study investigated the biological effects and adaptive responses induced by single and repeated in vivo computed tomography (CT) scans. We postulated that, through the induction of low-level oxidative stress, repeated low-dose CT scans (20 mGy, 2 days/week, 10 weeks) could protect mice (C57BL/6) from acute effects of high-dose radiation (1 Gy, 2 Gy). The micronucleated reticulocyte (MN-RET) count increased linearly after exposure to single CT scans of doses ranging from 20 to 80 mGy (P = 0.033). Ten weeks of repeated CT scans (total dose 400 mGy) produced a slight reduction in spontaneous MN-RET levels relative to levels in sham CT-scanned mice (P = 0.04). Decreases of nearly 10% in γ-H2AX fluorescence levels were observed in the repeated CT-scanned mice after an in vitro challenge dose of 1 Gy (P = 0.017) and 2 Gy (P = 0.026). Spontaneous apoptosis levels (caspase 3 and 7 activation) were also significantly lower in the repeated CT-scanned mice than the sham CT-scanned mice (P < 0.01). In contrast, mice receiving only a single CT scan showed a 19% elevation in apoptosis (P < 0.02) and a 10% increase in γ-H2AX fluorescence levels after a 2-Gy challenge (P < 0.05) relative to sham CT controls. Overall, repeated CT scans seemed to confer resistance to larger doses in mice, whereas mice exposed to single CT scans exhibited transient genotoxicity, enhanced apoptosis, and characteristics of radiation sensitization.

The contribution of chest CT-scan at diagnosis in children with unilateral Wilms' tumour. Results of the SIOP 2001 study

BACKGROUND

The SIOP 2001 nephroblastoma study hypothesised that patients with 'CT-only' pulmonary nodules would have the same outcome as patients with localised disease of same stage and histology.

PATIENTS

Unilateral Wilms' tumour (WT) patients, who had chest CT scans at diagnosis showing any sized pulmonary nodules undetected on chest X-ray, between November 2001 and November 2009, were selected from the SIOP 2001 database.

RESULTS

Among 2532 WT patients, 103 unilateral nephroblastoma patients with CT-only lung lesions were found. Thirty-seven patients received preoperative treatment according to the localised-disease protocol, and 66 according to the metastatic-disease protocol. The 3-year event-free survival (EFS) was 70% (95% CI: 55-89%) and 77% (95% CI: 66-89%), respectively. Corresponding 3-year overall survival (OS) was 89% (95% CI: 77-100%) and 85% (95% CI: 75-96%), respectively (p-value not significant). EFS and OS of all 2071 patients with true localised disease were 87% (95% CI: 86-89%) and 96% (95% CI: 94-97%), respectively. Patients with metastatic disease (n = 358) had 3-year EFS and OS estimates of 68% (95% CI: 63-74%) and 77% (95% CI: 72-82%), respectively.

CONCLUSIONS

EFS and OS of patients with CT-only lung lesions were inferior to that of true localised-disease patients and superior to that of patients with metastatic disease. However, no significant difference was found in EFS and OS between CT-only patients treated for localised or metastatic disease. The clinician's preference to treat patients with CT-only pulmonary nodules as metastatic disease is not evidence-based. Chest CT at diagnosis does not improve outcome but presents paediatric oncologists with a difficult dilemma.

A review of patient dose and optimisation methods in adult and paediatric CT scanning

An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along with tools that assist clinicians in the decision-making process. There is the potential to eliminate clinically non-indicated CT scans by replacing them with alternative examinations especially for children or patients receiving multiple CT scans.

Diagnostic radiation exposure in pediatric trauma patients

BACKGROUND

The amount of imaging studies performed for disease diagnosis has been rapidly increasing. We examined the amount of radiation exposure that pediatric trauma patients receive because they are an at-risk population. Our hypothesis was that pediatric trauma patients are exposed to high levels of radiation during a single hospital visit.

METHODS

Retrospective review of children who presented to Johns Hopkins Pediatric Trauma Center from July 1, 2004, to June 30, 2005. Radiographic studies were recorded for each patient and doses were calculated to give a total effective dose of radiation. All radiographic studies that each child received during evaluation, including any associated hospital admission, were included.

RESULTS

A total of 945 children were evaluated during the study year. A total of 719 children were included in the analysis. Mean age was 7.8 (±4.6) years. Four thousand six hundred three radiographic studies were performed; 1,457 were computed tomography (CT) studies (31.7%). Average radiation dose was 12.8 (±12) mSv. We found that while CT accounted for only 31.7% of the radiologic studies performed, it accounted for 91% of the total radiation dose. Mean dose for admitted children was 17.9 (±13.8) mSv. Mean dose for discharged children was 8.4 (±7.8) mSv (p<0.0001). Burn injuries had the lowest radiation dose [1.2 (±2.6) mSv], whereas motor vehicle collision victims had the highest dose [18.8 (±14.7) mSv].

CONCLUSION

When the use of radiologic imaging is considered essential, cumulative radiation exposure can be high. In young children with relatively long life spans, the benefit of each imaging study and the cumulative radiation dose should be weighed against the long-term risks of increased exposure.

Radiation Trends in Trauma Patients

Today, computed tomography (CT) and other studies are used more often early in a trauma case than X-rays, exposing patients to more radiation. The long-term effects of radiation exposure (RE) in trauma patients are of great concern. Investigators randomly selected 60 patients (injury severity scores 15-25) each from the years 2000, 2003, and 2006. The cumulative effective dose (CED) was calculated from the RE of all X-rays and CTs performed during the patient's hospital stay. Total CED/patient increased from 15.97 (2000) to 16.67 (2003) to 23.27 mSv (2006); the increase from 2000 to 2006 was significant ( P < 0.05). X-rays increased over the 6-year period from 9.6/patient (pt) to 11.4/pt to 15.4/pt. CT scans increased from 2.2/pt (15.19 mSv) to 3.5/pt (21.85 mSv, P < 0.05). The CED in children increased: 12.88 versus 13.17 versus 15.32 mSv/pt ( P > 0.05). RE was 19.5 versus 22.0 versus 27.1 mSv in 16 to 45-year-olds compared with 15.5 versus 14.3 versus 27.0 mSv in older adults. Sixteen to 45-year-olds had significantly higher RE than children ( P < 0.05). RE in the first hour and first 24 hours increased but not significantly ( P > 0.05). CED increased from 2000 to 2006, due primarily from CT scans. Children had no significant CED increase during the same period and had lower RE than 16 to 45-year-old adults.

Management of preseptal and orbital cellulitis

Orbital cellulitis describes an infection involving the soft tissues posterior to the orbital septum, including the fat and muscle within the bony orbit. This condition may be associated with severe sight and life-threatening complications. Despite significant advances in antimicrobial therapies and diagnostic technologies, the management of orbital cellulitis often remains challenging, and rapid diagnosis and prompt initiation of therapy are important in minimizing complications and optimizing outcomes. This review summarizes the distinctive characteristics of preseptal and orbital cellulitis, with a focus on anatomic considerations, predisposing conditions, approaches to evaluation, and management strategies.

Decreasing the effective radiation dose in pediatric craniofacial CT by changing head position

BACKGROUND

Children are exposed to ionizing radiation during pre- and post-operative evaluation for craniofacial surgery.

OBJECTIVE

The primary purpose of the study was to decrease effective radiation dose while preserving the diagnostic quality of the study.

MATERIALS AND METHODS

In this prospective study 49 children were positioned during craniofacial CT (CFCT) imaging with their neck fully extended into an exaggerated sniff position, parallel to the CT gantry, to eliminate the majority of the cervical spine and the thyroid gland from radiation exposure. Image-quality and effective radiation dose comparisons were made retrospectively in age-matched controls (n = 49).

RESULTS

When compared to CT scans reviewed retrospectively, the prospective examinations showed a statistically significant decrease in z-axis length by 16% (P < 0.0001) and delivered a reduced effective radiation dose by 18% (P < 0.0001). The subjective diagnostic quality of the exams performed in the prospective arm was maintained despite a slight decrease in the quality of the brain windows. There was statistically significant improvement in the quality of the bone windows and three-dimensional reconstructed images.

CONCLUSION

Altering the position of the head by extending the neck during pediatric craniofacial CT imaging statistically reduces the effective radiation dose while maintaining the diagnostic quality of the images.

Current issues in the diagnosis of pediatric cervical spine injury

Cervical spine injury in pediatric trauma occurs rarely; however, there is significant potential for considerable morbidity when it does occur. Screening for cervical spine injuries has been shown to be most sensitive in adult trauma centers when combined with reliable physical examination findings. Because pediatric trauma patients suffer from a different range of injuries than adults, and often are not reliable due to age limitations or associated head injury, the same strategies employed in adult trauma do not always hold true in children. We look at the differences in adult and pediatric cervical spine anatomy and traumatic mechanisms, as well as the differences between cervical spine injury in infants/children and adolescents/teens. In addition, we examine the literature currently available in each population and derive consensuses on the issues that are important in managing the pediatric cervical spine. We hope to provide a framework that trauma centers can use to develop safe and effective cervical spine clearance protocols.

Managing radiation risk in the evaluation of the pediatric trauma patient

Pediatric trauma is usually a nonoperative experience for the pediatric general surgeon. The pediatric trauma surgeon resuscitates the child and then evaluates and triages the identified injuries. A common diagnostic tool is the computed tomography (CT) scan. Most children who require evaluation for significant trauma will get a CT scan, but there are no national guidelines directing the assessment. Injuries to the head, cervical spine, chest, and abdomen can all be imaged with a CT scan; the question is whether the liberal approach to imaging children is appropriate. Over the past decade, concern has arisen about the radiation dose delivered by CT. This concern has generated a national campaign to "image gently." This article reviews the data involving the risk of medical radiation exposure and discusses strategies for managing the risk.

Chronic suppurative lung disease and bronchiectasis in children and adults in Australia and New Zealand

Consensus recommendations for managing chronic suppurative lung disease (CSLD) and bronchiectasis, based on systematic reviews, were developed for Australian and New Zealand children and adults during a multidisciplinary workshop. The diagnosis of bronchiectasis requires a high-resolution computed tomography scan of the chest. People with symptoms of bronchiectasis, but non-diagnostic scans, have CSLD, which may progress to radiological bronchiectasis. CSLD/bronchiectasis is suspected when chronic wet cough persists beyond 8 weeks. Initial assessment requires specialist expertise. Specialist referral is also required for children who have either two or more episodes of chronic (> 4 weeks) wet cough per year that respond to antibiotics, or chest radiographic abnormalities persisting for at least 6 weeks after appropriate therapy. Intensive treatment seeks to improve symptom control, reduce frequency of acute pulmonary exacerbations, preserve lung function, and maintain a good quality of life. Antibiotic selection for acute infective episodes is based on results of lower airway culture, local antibiotic susceptibility patterns, clinical severity and patient tolerance. Patients whose condition does not respond promptly or adequately to oral antibiotics are hospitalised for more intensive treatments, including intravenous antibiotics. Ongoing treatment requires regular and coordinated primary health care and specialist review, including monitoring for complications and comorbidities. Chest physiotherapy and regular exercise should be encouraged, nutrition optimised, environmental pollutants (including tobacco smoke) avoided, and vaccines administered according to national immunisation schedules. Individualised long-term use of oral or nebulised antibiotics, corticosteroids, bronchodilators and mucoactive agents may provide a benefit, but are not recommended routinely.

Imaging of back pain in children

While back pain presents less frequently in children than in adults, it still poses a significant clinical challenge with respect to making a firm diagnosis and developing an effective treatment plan. When children have back pain and medical attention is sought, an underlying pathology is usually suspected. Pediatric patients are evaluated, first, with a complete clinical history and examination and, second, by an imaging work-up that is based on initial findings, including the child's age and size, signs and symptoms, and suspected etiology. This article describes 1) the epidemiology of back pain in children, 2) the imaging work-up used, and 3) the correlation of imaging findings with disease entities that may cause back pain in the pediatric patient. The list of diseases giving rise to back pain is not meant to be exhaustive but rather reflective of the most commonly identified pathologies and disorders among young children and adolescents, from athletic injuries to lethal cancers.

Slitlike ventricle syndrome: a life-threatening presentation

Severely increased intracranial pressure can be life-threatening in shunted children who do not experience ventricular enlargement. This condition is termed normal ventricular hydrocephalus and represents the most severe form of slit ventricle syndrome.

CASE REPORT

A 7-year-old girl with a repaired lumbosacral myelomeningocele and shunted at birth who presented with headache, vomiting, seizure, and deterioration of level of consciousness was admitted to the pediatric intensive care unit. Because her ventricles were small to slitlike on cranial computed tomographic (CT) scan, the shunt was presumed to be working. Although the cerebrospinal fluid analysis was normal, she received initial empirical treatment of viral encephalitis. Twenty-four hours after admission, she evolved with apnea and bradycardia, requiring ventilatory support. Repeated CT scans were unchanged from one study to the next. After 48 hours, her condition worsened, and cerebrospinal pressure during lumbar puncture reached more than 30 mm Hg despite the serial CT scan disclosing no ventricular enlargement. She underwent a shunt revision that showed that the catheter was occluded and had adhered to the ventricular wall. The shunt was replaced, resulting in dramatic neurological improvement. This report highlights a life-threatening condition involving chronically shunted children who present severe intracranial hypertension without ventriculomegaly and may often be neglected or unrecognized by emergency physicians or general neurosurgeons.

MR and CT imaging of the pediatric patient with structural heart disease

Cardiac magnetic resonance imaging (MRI) and computed tomography (CT) are imaging modalities increasingly used in the diagnosis and management of structural heart disease. They are powerful imaging tools that have individual strengths and weaknesses. Rational choice between MRI and CT should be based on a sound understanding of these issues. Management guidelines that incorporate the use of MRI and CT are currently being developed, and their utilizations are expected to grow rapidly in the future.

Fluorine-18 DOPA-PET and PET/CT Imaging in Congenital Hyperinsulinism

Congenital hyperinsulinism is the principle cause of hypoglycemia during infancy but successful treatment is difficult and persistent hypoglycemia carries the risk of neurologic damage. Focal and diffuse abnormalities are the common forms of hyperinsulinism. Identification and localization of focal hyperinsulinism can be cured by partial pancreatectomy. It has been shown that affected pancreatic areas utilize LDOPA in a higher rate than normal pancreatic tissue and, thus, labeling L-DOPA with fluorine-18 (FDOPA) allows functional mapping of hyperinsulinism using PET. This article presents a fundamental overview of the genetics background, pathology, management, and the role of FDOPA-PET imaging in hyperinsulinism.

Childhood exposure to external ionising radiation and solid cancer risk

The increasing use of ionising radiation for diagnostic purposes has raised concern about potential iatrogenic damage, especially in children. In this review, we discuss some aspects of radiation-induced cancer in relation to age at exposure and measures that should be taken for limiting exposure in this sensitive population.