Treatment planning with a 2.5 MV photon beam for radiation therapy.

Purpose: The shallow depth of maximum dose and higher dose fall-off gradient of a 2.5 MV beam along the central axis that is available for imaging on linear accelerators is investigated for treatment of shallow tumors and sparing the organs at risk (OARs) beyond it. In addition, the 2.

Regional Vascular Changes and Aortic Dilatation in Pediatric Patients With Bicuspid Aortic Valve.

Background: Bicuspid aortic valve (BAV) is the most common congenital heart disease, often associated with valve dysfunction, coarctation of the aorta, and ascending aorta dilatation. Aortic dilatation might result from abnormal regional hemodynamics or inherent vascular disease. Vascular function in pediatric BAV remains poorly characterized.

Valve disease and aortopathy associations of bicuspid aortic valve phenotypes differ between men and women.

Objective: Determine whether associations between bicuspid aortic valve (BAV) phenotypes, valve disease and aortopathy differ between sexes.

Methods: 1045 patients with BAV (76.0% men, n=794) from two surgical centres were included in this cross-sectional study.

Diagnosis of Pediatric Hypertension: European Society of Hypertension-Recommended 24-Hour vs. 24-Hour-Day-Night Ambulatory Blood Pressure Thresholds.

Background: The impact of diagnosing pediatric hypertension based on all three-24-hour, day and night ambulatory blood pressure (ABP) thresholds (combined ABP threshold) vs. conventionally used 24-hour ABP threshold is not known.

Methods: In this cross-sectional, retrospective study from a tertiary care outpatient clinic, we evaluated the diagnosis of hypertension based on the 24-hour European Society of Hypertension (ESH) and combined ESH ABP thresholds in untreated children with essential hypertension.

Prenatal Diagnosis of Transposition of the Great Arteries Reduces Postnatal Mortality: A Population-Based Study.

Background: Transposition of the great arteries (TGA) may present as a life-threatening neonatal malformation. Although prenatal detection facilitates the perinatal management, the impact on outcome is controversial.

Methods: This study reviewed the differences in prenatal diagnosis of TGA from 2009 to 2014 among the 5 geographic areas in Ontario and compared the management, morbidity, and mortality among neonates with a prenatal (prenatal cohort; n = 70) vs a postnatal (postnatal cohort; n = 76) anomaly diagnosis.

IPEM code of practice for high-energy photon therapy dosimetry based on the NPL absorbed dose calibration service.

The 1990 code of practice (COP), produced by the IPSM (now the Institute of Physics and Engineering in Medicine, IPEM) and the UK National Physical Laboratory (NPL), gave instructions for determining absorbed dose to water for megavoltage photon (MV) radiotherapy beams (Lillicrap et al 1990). The simplicity and clarity of the 1990 COP led to widespread uptake and high levels of consistency in external dosimetry audits. An addendum was published in 2014 to include the non-conventional conditions in Tomotherapy units.

Comparative Analysis of American Heart Association and European Society of Hypertension Ambulatory Blood Pressure Thresholds for Diagnosing Hypertension in Children.

Introduction: The influence of using 24-hour ambulatory blood pressure (ABP) thresholds recommended by the American Heart Association (AHA) (24-hour mean ABP >95th percentile and ABP load >25%) or the European Society of Hypertension (ESH) (mean 24-hour ABP >95th percentile or >130/80 mm Hg if mean ABP 95th percentile exceeds 130/80 mm Hg) on the diagnosis of pediatric hypertension has been understudied.

Methods: In a cross-sectional, retrospective study of 159 children from a tertiary care outpatient clinic, we classified office blood pressure (OBP) as normotension or hypertension based on the OBP thresholds recommended by the American Academy of Pediatrics (AAP) and the fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents (herein referred to as the fourth report) by the National High Blood Pressure Educational Program Working Group on High Blood Pressure in Children and Adolescents separately. Thereafter, we evaluated the agreement between the ambulatory AHA and ESH thresholds for diagnosing normotension, white-coat hypertension (WCH), masked hypertension (MH), and hypertension based on the patient's ABP and OBP hypertension pattern.

Lower prevalence of aortic dilatation among preemptive pediatric renal transplant recipients - A cross-sectional cohort study.

Background: Aortic dilatation is a cardiovascular complication in pediatric renal transplant recipients and may have an increased risk of aortic dissection, aortic rupture, and death. Studies failed to show an association between blood pressure and aortic dilatation; however, 24-hours ambulatory blood pressure monitoring (ABPM) was not performed. There was also no comparison between preemptive transplantation and dialysis.

Predictors of Bicuspid Aortic Valve-Associated Aortopathy in Childhood: A Report From the MIBAVA Consortium.

Background: Bicuspid aortic valve (BAV) is the most prevalent congenital heart defect affecting 1% to 2% of the population. It is associated with ascending aorta dilatation. Valve morphology, aortic stenosis (AS), and aortic insufficiency (AI) have been proposed as potential risk factors; however, evaluating their role is difficult, as these factors are inherently related.

Infective Endarteritis and Mycotic Pseudoaneurysms in a Pediatric Patient With Aortic Coarctation.

An 11-year-old boy presented with Staphylococcus aureus infective endarteritis and mycotic pseudoaneurysms within the context of a previously undiagnosed aortic coarctation. He had an urgent resection of the pseudoaneurysm and coarctation repair. Nuances to his initial diagnosis and key learning points related to the complication of pseudoaneurysm are discussed.

Increased blood pressure is associated with increased carotid artery intima-media thickness in children with repaired coarctation of the aorta.

Objectives: The intima-media thickness of the common carotid artery (cIMT) is a good noninvasive surrogate marker for cardiovascular disease. Regular cIMT monitoring in children with congenital heart disease has great potential. We sought to determine which anthropomorphic and haemodynamic variables were significantly associated with the cIMT in paediatric patients with obesity and children with repaired coarctation of the aorta (CoA).

Ventricular Torsion in Young Patients With Single-Ventricle Anatomy.

Background: In normal left ventricles, clockwise basal rotation and counterclockwise apical rotation result in systolic torsion. Torsion is important for contractile efficiency and may be especially important in single-ventricle (SV) physiology. However, little is known about torsion in patients with SVs.

Non-invasive measurement of cardiac output in children with repaired coarctation of the aorta using electrical cardiometry compared to transthoracic Doppler echocardiography.

Objective: To evaluate the equivalence of the ICON electrical cardiometry (EC) haemodynamic monitor to measure cardiac output (CO) relative to transthoracic Doppler echocardiography (TTE) in paediatric patients with repaired coarctation of the aorta (CoA).

Approach: A group of n  =  28 CoA patients and n  =  27 matched controls were enrolled. EC and TTE were performed synchronously on each participant and CO measurements compared using linear regression and Bland-Altman analysis.

Relationship between serum inflammatory markers and vascular function in a cohort of adolescents with type 1 diabetes.

Objective: The contribution of inflammation to endothelial/vascular dysfunction in early Type I Diabetes (T1D) is not well understood. The objective of this study was to examine the interaction between systemic inflammation and vascular function in adolescent's with and without-T1D.

Methods: 51 subjects from our observational cohort of adolescents with T1D (JDRF-CCTN), and 59 healthy controls (HC) were studied.

Longitudinal assessment of myocardial function in childhood chronic kidney disease, during dialysis, and following kidney transplantation.

Background: Childhood chronic kidney disease (CKD) and dialysis are associated with increased long-term cardiovascular risk. We examined subclinical alterations in myocardial mechanics longitudinally in children with CKD, during dialysis, and following renal transplantation.

Methods: Forty-eight children with CKD (stage III or higher) who received kidney transplants from 2008 to 2014 were included in a retrospective study and compared to 192 age- and sex-matched healthy children.

Mechanics of the Functionally Univentricular Heart-How Little Do We Understand and Why Does It Matter?

Despite improved surgical techniques, preoperative and postoperative care, patients with functionally univentricular hearts (UVH) continue to have high morbidity and mortality and a decreased lifespan. Ventricular systolic and diastolic dysfunction is a major contributing factor to Fontan patient outcome. The evaluation of ventricular function in patients with UVH is particularly challenging.

The Impact of Infective Endocarditis Prophylaxis Recommendations on the Practices of Pediatric and Adult Congenital Cardiologists.

Background: Compliance with the April 2007 American Heart Association (AHA) infective endocarditis (IE) guidelines is not well described. We sought to evaluate the impact of these guidelines on the clinical practices of pediatric and adult congenital cardiologists.

Methods: We conducted a 2-centre retrospective cohort study, including patients who had at least 1 outpatient cardiology visit after April 1, 2008 and had 1 of 11 prespecified high- or low-risk congenital cardiac lesions.

A review of recent advances in optical fibre sensors for in vivo dosimetry during radiotherapy.

This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry.

Echocardiographic assessment of ventricular function in pediatric patients: a comprehensive guide.

Assessment of ventricular function is an important part of every echocardiographic examination. Specific pediatric guidelines on quantification of ventricular function are available, but technology evolves quickly and it generally takes long before newer techniques are integrated into routine clinical practice and are adopted by the guidelines. In the current overview, we would like to present our experience with integrating newer echocardiographic techniques for assessing ventricular function in children using a comprehensive state-of-the-art echocardiographic functional protocol.

Maternal hypothyroidism may be associated with CHD in offspring.

Objectives: This study tested whether mothers with maternal hypothyroidism have increased odds of CHD in their offspring, and examined the relationship between CHD, maternal thyroid function, and nausea and vomiting in pregnancy.

Background: Maternal hypothyroidism increases the risk for foetal demise and prematurity and can have a negative impact on neurodevelopment. Prior studies have postulated a relationship between maternal thyroid function, CHD, and maternal nausea and vomiting in pregnancy.

Monitoring daily MLC positional errors using trajectory log files and EPID measurements for IMRT and VMAT deliveries.

This work investigated the differences between multileaf collimator (MLC) positioning accuracy determined using either log files or electronic portal imaging devices (EPID) and then assessed the possibility of reducing patient specific quality control (QC) via phantom-less methodologies. In-house software was developed, and validated, to track MLC positional accuracy with the rotational and static gantry picket fence tests using an integrated electronic portal image. This software was used to monitor MLC daily performance over a 1 year period for two Varian TrueBeam linear accelerators, with the results directly compared with MLC positions determined using leaf trajectory log files.

Octavius 4D characterization for flattened and flattening filter free rotational deliveries.

Purpose: In this study the Octavius detector 729 ionization chamber (IC) array with the Octavius 4D phantom was characterized for flattening filter (FF) and flattening filter free (FFF) static and rotational beams. The device was assessed for verification with FF and FFF RapidArc treatment plans.

Methods: The response of the detectors to field size, dose linearity, and dose rate were assessed for 6 MV FF beams and also 6 and 10 MV FFF beams.

Analysis of output trends from Varian 2100C/D and 600C/D accelerators.

Analysis of Varian linear accelerator output trends is reported. Two groups, consisting of four matched Varian 2100C/D and four matched Varian 600C/D accelerators, with different designs of monitor chamber, have been investigated and the data acquired from regular calibrated ion chamber/electrometer measurements of the output performance of the eight accelerators analysed. The trend of machine output with time, having removed the effect of adjusting the monitor chamber response, was compared on a monthly and annual basis for monitor chambers with ages ranging between 1 year and 7 years.