THE IMPACT OF DIGITAL TECHNOLOGY ON DOSE REDUCTION IN PAEDIATRIC CARDIAC CATHETERISATION WITHIN A LARGE METROPOLITAN CHILDREN'S HOSPITAL.

This study examines the kerma-area product (PKA) levels from paediatric cardiac catheterisations at a major Children's Hospital over three different time periods in order to gain an understanding of the causation of dose variations over time and to present a model for dose reduction. A retrospective review of 1245 paediatric procedural records was undertaken. This cohort consisted of patients that were catheterised over a period from November 2007 to July 2009, October 2009 to November 2011 and January 2016 to December 2016. The age distribution was from newborn to 18 years. Archived (PKA) readings were retrieved and analysed. The 75th percentile PKA values for the specific age categories over time periods (1, 2, 3) were 0-30 days-(5.47, 1.37, 1.37) Gy cm2; 1-12 months-(6.42, 2.03, 1.06) Gy cm2; 1-3 years-(11.25, 3.20, 1.25) Gy cm2; 3-5 years-(12.65, 3.72, 2.88) Gy cm2; 5-10 years-(12.80, 8.53, 3.52) Gy cm2; 10-15 years-(27.92, 10.85, 2.97) Gy cm2; >15 years-(29.09, 27.81, 11.65) Gy cm2. Using newer imaging technologies, optimising dose reduction strategies and regular dose auditing can transform radiation dose delivery for paediatric x-ray examinations. Our centre provides a template for dose reduction success worldwide.

Cumulative Effective and Individual Organ Dose Levels in Paediatric Patients Undergoing Multiple Catheterisations for Congenital Heart Disease.

This study examines the cumulative radiation dose levels received by a group of children who underwent multiple cardiac catheterisation procedures during the investigation and management of congenital heart disease (CHD). The purpose is to calculate cumulative doses, identify higher dose individuals, outline the inconsistencies with risk assessment and encourage the establishment of dose databases in order to facilitate the longitudinal research necessary to better understand health risks. A retrospective review of patient records for 117 paediatric patients who have undergone two or more cardiac catheterisations for the investigation of CHD was undertaken. This cohort consisted of patients who were catheterised over a period from September 2002 to August 2014. The age distribution was from newborn to 17 y. Archived kerma-area product (PKA) and fluoroscopy time (T) readings were retrieved and analysed. Cumulative effective and individual organ doses were determined. The cumulative PKA levels ranged from 1.8 to 651.2 Gycm2, whilst cumulative effective dose levels varied from 2 to 259 mSv. The cumulative fluoroscopy time was shown to vary from 8.1 to 193.5 min. Median cumulative organ doses ranged from 3 to 94 mGy. Cumulative effective dose levels are highly variable but may exceed 250 mSv. Individual organ and effective dose measurements remain useful for comparison purposes between institutions although current methodologies used for determining lifetime risks are inadequate.

Bioreactivity of particulate matter in Beijing air: results from plasmid DNA assay.

An in vitro plasmid assay was employed to study the bioreactivity of PM (particulate matter) in Beijing air. It was found that the TD20 (toxic dose of PM causing 20% of plasmid DNA damage) of Beijing PM can be as low as 28 microg ml(-1) and as high as >1000 microg ml(-1). Comparison of the physical properties, such as morphology and size distribution, and oxidative potential indicates that the PM(2.5) (particulate matter with an aerodynamic diameter of 2.5 microm or less) has a stronger oxidative capacity than PM(10) (particulate matter with an aerodynamic diameter of 10 microm or less), and that the higher number percentages of soot aggregates and lower number percentages of mineral and fly ashes are associated with the higher oxidative capacity. Although the mass of PM(10) during dust storms is commonly 5 times higher than that during non-dust storm episodes, the oxidative capacity of PM(10)s of dust storms is much lower than that of the non-dust storm PM(10)s. The water-soluble fractions and intact whole particle solutions of Beijing airborne particles produce similar plasmid assay results, demonstrating that the bioreactivity of Beijing airborne particles is mainly sourced from the water-soluble fraction. In the samples with stronger bioreactivity, the total analyzed water soluble Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Pb (ppm) concentrations are higher. The water soluble zinc shows a good negative correlation with TD20s, suggesting that the water-soluble zinc is probably the major element responsible for the plasmid DNA damage.

The spatial and temporal variations in PM10 mass from six UK homes.

People spend the majority of their time indoors mostly in the domestic environment, where their health may be effected by significant airborne particulate pollution. The indoor/outdoor air quality at six homes in Wales and Cornwall was investigated, based on different locations (urban, suburban, rural) and household characteristics (smokers, non-smokers). The spatial and temporal variations in PM10 mass were monitored for a calendar year, including ambient weather conditions. The activities of individuals within a household were also recorded. Monitoring of PM10 took place inside (kitchen, living room, bedroom) homes, along with concomitant collections outdoors. Samples were subjected to gravimetric analysis to determine PM10 concentrations and examined by scanning electron microscopy to identify the types of particles present on the filters. The results of the study show there are greater masses of PM10 indoors, and that the composition of the indoor PM10 is controlled by outdoor sources, and to a lesser extent by indoor anthropogenic activities, except in the presence of tobacco smokers. The indoor and outdoor PM10 collected was characterised as being a heterogeneous mixture of particles (soot, fibres, sea salt, smelter, gypsum, pollen and fungal spores).

Pulmonary epithelial response in the rat lung to instilled Montserrat respirable dusts and their major mineral components.

BACKGROUND: The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. AIMS: To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz). METHODS: Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes. RESULTS: Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage. CONCLUSION: Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation.

[Physicochemical characterization of the PM10 in ambient air of northwestern Beijing urban area during heating-period].

Based on monitoring data, the daily and day-to-day changes of PM10 mass concentrations in northwestern Beijing urban area during heating-period were discussed. XRD and SEM were applied to study the mineral compositions and morphology of the PM10, respectively. It was concluded that concentration of PM10 at nighttime was higher than that at daytime generally. By XRD analysis, it was found that the finer the particles, the less the minerals in it. Furthermore, from the SEM micrograph, five types of the particles, mostly from coal burning and diesel exhaust in number concentration, were classified as chain-like aggregate, cluster aggregate, spherical particle, flake-like particle and non-regular particle.

Skin biopsy indications in primary care practice: a population-based study.

BACKGROUND: To better understand skin biopsy practice among primary care providers, we sought to describe (1) the type and variability of skin lesions biopsied within a defined population, (2) the providers' previous skin cancer experience in clinical practice, and (3) how providers are alerted to the lesions. METHODS: Our study was based upon 1215 skin biopsies done by family physicians, internists, physician assistants, and certified nurse midwives at a health maintenance organization between June 1989 and February 1992. Biopsy reports were reviewed, and providers were both surveyed and interviewed. RESULTS: There were 1004 benign, 89 premalignant, and 122 malignant skin lesions removed for biopsy by 47 primary care providers. The five most frequent biopsy diagnoses were nevi, seborrheic keratoses, actinic keratoses, cysts, and dermatofibromas. Personal interviews indicated that providers noticed lesions based on their experience with pictures, text descriptions, or variation from expected growth, behavior, or response to treatment. Seventy percent of providers interviewed stated that most often the patient brought the lesion to the attention of the provider. CONCLUSIONS: Among the skin lesions examined by biopsy in this primary care setting, 82.6 percent were benign, 7.3 percent were premalignant, and 10.0 percent were malignant. Worthy educational objectives suggested by this study include (1) meeting primary care providers' need for information about early detection of skin cancers, (2) increasing provider access to visual dermatology resources, and (3) increasing patient awareness of skin cancers.

Protein synthesis and amylase messenger RNA content in rat parotid salivary glands after total or partial stimulation with isoproterenol.

The rate of synthesis of secretory proteins increases significantly in rat parotid glands after stimulated discharge of stored proteins. How any difference in the amount of secretory protein discharge affects the rate of subsequent protein synthesis, and whether this post-secretory synthesis is regulated at the level of messenger RNA, was now examined. One group of rats was stimulated to secrete 97% of stored secretory proteins by an intraperitoneal injection of isoproterenol. The other group received a much smaller dose to induce the discharge of about 40% of the proteins. Despite this difference in secretion, the subsequent rates of total protein synthesis, as well as of amylase, were increased to about the same extent. The amylase messenger RNA (mRNA) was identified and quantified by hybridization with a 32P-labelled amylase complementary DNA (cDNA) probe. The amylase mRNA in stimulated and unstimulated rats was of the same molecular size (Northern blot analyses). The amount of amylase mRNA, determined by dot blot analyses, were also increased in stimulated rats, although this increase was not as great as that in the rate of amylase protein synthesis. The implications of this discrepancy concern the possibility that the mechanism of regulation of secretory protein synthesis in parotid glands is at the translational level.

Induced-transmission interference-filter array for multiwavelength pyrometry.

The design and construction of an induced-transmission interference-filter array for use in multiwavelength pyrometry are described. The array which covers the 0.75-1.70-microm wavelength range is shown to be both an efficient beam splitter and wavelength selector. Fabrication details of the filters are provided with a complete description of the pyrometer system.