Study on the dose profile in CT-fluoroscopy.

This work aims to contribute to the description of the dose profile in Computed Tomography Fluoroscopy (CTF). Our approach uses a function model to fit the single slice dose profiles (SSDP) for any point inside the gantry of the CT unit, with special attention to points off the rotation axis. The function model was successfully tested with measurements performed using GafChromic film. The parameters of the SSDP at the rotation axis (isocenter) and at 8 cm and 16 cm off the isocenter were determined. The model allows an estimation of the slice thickness at the isocenter and for points at 8 cm and 16 cm off the isocenter. The differences between the slice thicknesses results in overestimation of the Computed Tomography Dose Index, CTDI, by values as high as 20% if the nominal slice thickness instead of the model estimated value is used. The results obtained in this work provided a good description of the dose profiles, which can be used in further studies such as comparisons with measurements performed with phantoms and patients.

Recommendations for the use of active personal dosemeters (APDs) in interventional workplaces in hospitals.

Occupational radiation doses from interventional procedures have the potential to be relatively high. The requirement to optimise these doses encourages the use of electronic or active personal dosimeters (APDs) which are now increasingly used in hospitals. They are typically used in tandem with a routine passive dosimetry monitoring programme, with APDs used for real-time readings, for training purposes and when new imaging technology is introduced. However, there are limitations when using APDs. A survey in hospitals to identify issues related to the use of APDs was recently completed, along with an extensive series of APD tests by the EURADOS Working Group 12 on Dosimetry for Medical Imaging. The aim of this review paper is to summarise the state of the art regarding the use of APDs. We also used the results of our survey and our tests to develop a set of recommendations for the use of APDs in the clinical interventional radiology/cardiology settings, and draw attention to some of the current challenges.

THE USE OF ACTIVE PERSONAL DOSEMETERS IN INTERVENTIONAL WORKPLACES IN HOSPITALS: COMPARISON BETWEEN ACTIVE AND PASSIVE DOSEMETERS WORN SIMULTANEOUSLY BY MEDICAL STAFF.

Medical staff in interventional procedures are among the professionals with the highest occupational doses. Active personal dosemeters (APDs) can help in optimizing the exposure during interventional procedures. However, there can be problems when using APDs during interventional procedures, due to the specific energy and angular distribution of the radiation field and because of the pulsed nature of the radiation. Many parameters like the type of interventional procedure, personal habits and working techniques, protection tools used and X-ray field characteristics influence the occupational exposure and the scattered radiation around the patient. In this paper, we compare the results from three types of APDs with a passive personal dosimetry system while being used in real clinical environment by the interventional staff. The results show that there is a large spread in the ratios of the passive and active devices.

Dose to the interventional radiologist in CTF-guided procedures.

The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the body including the hands and fingers; to suggest recommendations for individual monitoring; and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, Hp(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, Hp(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess Hp(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36-39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; Hp(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information.

Perinatal outcomes after open fetal surgery for myelomeningocele repair: a retrospective cohort study.

OBJECTIVE: Describe outcomes of open fetal surgery for myelomeningocele (MMC) repair in two Brazilian hospitals and the impact of surgical experience on outcome. DESIGN: Retrospective cohort study. SETTING: Sao Paulo, Brazil. POPULATION: 237 pregnant women carrying a fetus with an open spinal defect. METHODS: Surgical details, and maternal and fetal outcomes collected from all patients. MAIN OUTCOME MEASURES: Analysis of surgical and perinatal outcome parameters. RESULTS: Total surgical time was 119 ± 7.6 minutes. Preterm labour occurred in 24.2%, premature rupture of membranes in 26.7%, placental abruption in 0.8%, need for a blood transfusion at delivery in 2.1%, and dehiscence at the repair site in 2.5%. Reversal of hindbrain herniation at birth occurred in 71.4%. There were no maternal deaths or severe maternal morbidities. The failure rate with the patient anaesthetised was 0.42% and perinatal mortality was 2.1% (three intrauterine demises and two neonatal deaths). Comparing results from our study in the first 3 years with the last 3 years demonstrated improvement in the total surgical time (121.2 ± 6.4 versus 118.5 ± 8.2 minutes, P = 0.005) and an increase in reversal of hindbrain herniation at birth (64.0 versus 77.1%, P = 0.042). CONCLUSION: Our open fetal surgical approach for MMC was effective and results were comparable to past studies. Improvements in surgical performance and perinatal outcome increased as the surgical team became more familiar with the procedure. FUNDING: The study was funded solely by institutional funds. TWEETABLE ABSTRACT: Brazilian experience of in utero open surgery for myelomeningocele repair.

Amniotic fluid lactic acid and matrix metalloproteinase-8 levels at the time of fetal surgery for a spine defect: association with subsequent preterm prelabour rupture of membranes.

OBJECTIVE: In utero fetal surgery to correct incomplete closure of the spinal cord lessens the extent of permanent damage but is associated with preterm prelabour rupture of membranes (PPROM). We determined whether compounds in amniotic fluid collected at the time of surgery predicted subsequent development of PPROM. DESIGN: Prospective study. SETTING: Hospitals in Sao Paulo, Brazil. POPULATION: Twenty-four consecutive pregnant women at 24-26 weeks of gestation seen between February and October 2017 with a singleton pregnancy underwent in utero surgery to correct an open spinal defect in their fetus. METHODS: Amniotic fluid was tested for lactic acid, matrix metalloproteinase 2 (MMP-2), MMP-8, MMP-9 and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay. Clinical data were collected after completion of all laboratory studies. MAIN OUTCOME MEASURE: Amniotic fluid concentration of compounds in women with or without PPROM. RESULTS: Preterm prelabour rupture of membranes occurred in seven (29.2%) women. There were no differences in maternal age, gravidity, parity, race, history of caesarean sections or fetal gender between women with or without PPROM. Length of surgery, days of wound healing and length of hospital stay were also indistinguishable. The median concentrations of MMP-8 (1.7 versus 0.6 ng/ml; P = 0.0041) and lactic acid (7.1 versus 5.9 mm; P = 0.0181) were higher in women with PPROM. The amniotic fluid MMP-8 level was also negatively correlated with gestational age at delivery (Spearman r = -0.4217, P = 0.0319). CONCLUSION: Differences in susceptibility to develop PPROM are present before fetal surgery. An increase in anaerobic glycolysis, evidenced by the intra-amniotic lactic acid level, may enhance MMP-8 production and weaken maternal and fetal membranes. TWEETABLE ABSTRACT: Matrix metalloproteinase-8 and lactic acid in amniotic fluid predict preterm prelabour rupture of membranes.

A Review of Radiation Protection Requirements and Dose Estimation for Staff and Patients in CT Fluoroscopy.

The combination of fluoroscopically guided interventional procedures with computed tomography (CTF) has become widespread around the world. The benefits of CTF include the ability to obtain a real-time visualization of the entire body, increased target accuracy and improved visualization of biopsy needles. Modern CTF units work with variable frame rates for image selection, and therefore the dose distributions for patients and staff can considerably vary, creating growing concern in terms of the occupational exposure of interventionists and the drawback of a higher exposure of the patient. A literature review of the latest CTF publications is summarized in this article. A wide range of CTF studies reveal different treatment methods used in clinical practice, and therefore the differences in the exposures between them; as well as in the radiation protection tools and dose monitoring. Further optimization of radiation protection methods, harmonization of exposure patterns as well as training and education of CTF staff on the basis of the information in the survey, are strongly recommended.

Association between atmospheric pollutants and hospital admissions in Lisbon.

Ambient air pollution is recognised as one of the potential environmental risk factors causing health hazards to the exposed population, demonstrated in numerous previous studies. Several longitudinal, ecological and epidemiological studies have shown associations between outdoor levels of outdoor atmospheric pollutants and adverse health effects, especially associated with respiratory and cardiovascular hospital admissions. The aim of this work is to assess the influence of atmospheric pollutants over the hospital admissions in Lisbon, by Ordinary Least Squares Linear Regression. The pollutants (CO, NO, NO2, SO2, O3, PM10 and PM2.5) were obtained from 13 monitoring stations of the Portuguese Environmental Agency, which provide hourly observations. Hospital admission data were collected from the Central Administration of the Health System and were compiled by age: <15, 15-64, >64 years old. The study period was 2006-2008. Results showed significant positive associations between the following: (1) the pollutants CO, NO, NO2, SO2, PM10 and PM2.5 and circulatory diseases for ages between 15 and 64 years (0.5% hospital admissions (HA) increase with 10 µg m(-3) NO increase) and above 64 years (1.0% stroke admission increase with 10 µg m(-3) NO2 increase); (2) the pollutants CO, NO, NO2, SO2, PM10 and PM2.5 and respiratory diseases for ages below 15 years (up to 1.9% HA increase with 10 µg m(-3) pollutant increase); and (3) the pollutants NO, NO2 and SO2 and respiratory diseases for ages above 64 years (1.3% HA increase with 10 µg m(-3) CO increase).

Tuberculosis in pregnancy:a challenging differential diagnosisfor inflammatory bowel disease.

OBJECTIVE: To describe a case of tuberculosis with intestinal variant in a pregnant woman in the 17th week of pregnancy. DESIGN: Case report. SETTING: Department of Obstetrics, Federal University of São Paulo (UNIFESP), São Paulo-SP, Brazil. CONCLUSION: Tuberculosis is a public health problem that concerns many countries in the world. It was declareda public emergency by the World Health Organization in 2005. Its presence during pregnancy brings maternal risk and fetal impairment if not treated quickly and properly. The intestinal variant is not the most common form of the disease and may be confused with inflammatory bowel diseases, especially Crohns disease. Knowledge of the specific characteristics, combined with a detailed medical history and appropriate diagnostic methods can make all the difference in gestational prognosis. We report the case of a pregnant woman who wrongly underwent treatment for inflammatory bowel disease at another service. After admission to our university hospital, fruitful diagnostic clarification was achieved and the patient was diagnosed and treated for tuberculosis. We describe the details of the investigation and, in particular, review the main characteristics in the literature for differentiating the two diseases.

Effects of exposure to particles and ozone on hospital admissions for cardiorespiratory diseases in SetúBal, Portugal.

In recent years, the adverse health effects attributed to air pollution have been a focus of intense study. Exposure to pollutants such as airborne particulate matter (PM) and ozone (O3) has been associated with increases in morbidity and mortality due to respiratory and cardiovascular diseases. The aim of this study was to determine a correlation between particles (PM10, PM2.5) and O3 with hospital admissions in Setúbal, a densely populated Portuguese urban region that coexists with a heavy industrial area. A database with daily air quality and hospital admission data over 5 years (2005-2009) was assembled and associations were investigated by ordinary least squares linear regression. Results showed positive significant associations between PM10 and respiratory diseases for ages below 14 yr and above 64 yr, and between PM2.5 and respiratory diseases for ages above 64 yr.

Preliminary assessment of the dose to the interventional radiologist in fluoro-CT-guided procedures.

A preliminary assessment of the occupational dose to the intervention radiologist received in fluoroscopy computerised tomography (CT) used to guide the collection of lung and bone biopsies is presented. The main aim of this work was to evaluate the capability of the reading system as well as of the available whole-body (WB) and extremity dosemeters used in routine monthly monitoring periods to measure per procedure dose values. The intervention radiologist was allocated 10 WB detectors (LiF: Mg, Ti, TLD-100) placed at chest and abdomen levels above and below the lead apron, and at both right and left arms, knees and feet. A special glove was developed with casings for the insertion of 11 extremity detectors (LiF:Mg, Cu, P, TLD-100H) for the identification of the most highly exposed fingers. The H(p)(10) dose values received above the lead apron (ranged 0.20-0.02 mSv) depend mainly on the duration of the examination and on the placement of physician relative to the beam, while values below the apron are relatively low. The left arm seems to receive a higher dose value. H(p)(0.07) values to the hand (ranged 36.30-0.06 mSv) show that the index, middle and ring fingers are the most highly exposed. In this study, the wrist dose was negligible compared with the finger dose. These results are preliminary and further studies are needed to better characterise the dose assessment in CT fluoroscopy.

Correlating element atmospheric deposition and cancer mortality in Portugal: data handling and preliminary results.

This study, framed within geographical epidemiology, presents preliminary findings concerning the association between the concentrations of chemical elements obtained through atmospheric biomonitoring with lichens and cancer mortality in the Portuguese population. Exploratory analyses were performed to identify potential confounders for the relationships between chemical elements and neoplasm mortality and to assess the extent of their interference. The results of this study highlight some methodological and conceptual difficulties inherent to observational and geographical studies, in the specific context of the Portuguese population, and the challenge posed by the large numbers of pollutants considered.

Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution.

A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.

[Vascular stroke of the brain stem. Study of 21 cases]. / Acidente vascular de tronco encefálico. Estudo de 21 casos.

A prospective study was designed to follow patients with syndromes of brain stem during 12 months (in 1991-1992). The aim was to correlate clinical and radiologic findings and comparing them with the classical descriptions of brain stem syndromes. Twenty one consecutive patients were admitted at the Hospital de Base do Distrito Federal. The diagnosis and the follow up were carried out by neurological examination and neuroradiologic images: CT (100%), angiography (24%, 5) and MRI (5%, 1). Hypertension and old age were the most important risk factors and hemorrhage at pons with extension to midbrain was the most frequent finding. Coma at admission was associated to a poor outcome. The outcome was defined by the Glasgow Outcome Scale: 28% rated 5, 24% rated 4, 5% rated 3, 28% rated 2 and 14% rated 1. Our results show that the clinical presentation of ischemic strokes and hemorrhages of the brain stem very frequently follow a mixed pattern, which do not conciliate with the classical of these syndromes.