Surgeon radiation exposure in hip arthroscopy: A prospective analysis

Objectives: Hip arthroscopy is an established field within orthopaedic surgery. The majority of the procedures involve repairs of the acetabular labrum and arthroscopic treatment of femoroacetabular impingement (FAI). The procedures are being performed with increasing frequency annually. Fluoroscopic guidance is recommended during these procedures, and radiation exposure to the surgeon, staff, and patient remains a valid concern. The purpose of this study is to measure radiation exposure to the surgeon during hip arthroscopy and determine if this exposure remains below recommended annual occupational radiation exposure thresholds recommended by the International Committee on Radiological Protection (IRCP). Methods: Prospectively, radiation exposure was measured for a single surgeon at a single outpatient facility for all hip arthroscopic procedures over a three-year period. A radiation dosimeter was worn outside of the surgeon’s chest on the lead apron. Standard pre-operative and intra-operative imaging was used for all patients. Radiation readings were prospectively measured for deep dose equivalent (DDE), lens dose equivalent (LDE), and shallow dose equivalent (SDE). The cumulative radiation exposure was tabulated in millirem (mrem), converted to milli-Sieverts (mSv) (standard measurement used by the IRCP) and then the per-patient exposure calculated as well as annual exposure for 100 hip arthroscopies per year. Results: Between July 2011 and July 2014, 209 patients underwent a total of 280 hip arthroscopy procedures at a single facility by a single surgeon. There were 90 labral repairs, 83 femoroplasties, 26 acetabuloplasties, 66 labral debridements, 8 trochanteric bursectomies, and 7 iliopsoas releases. The cumulative DDE was 183 mrem (1.83 mSv), LDE 183 mrem (1.83 mSv), and SDE 176 mrem (1.76 mSv). The calculated per patient exposure for the surgeon was DDE 0.875 mrem (0.00875 mSv), LDE 0.875 mrem (0.00875 mSv), and SDE 0.842 mrem (0.00843 mSv). Calculated annual exposure for a surgeon performing 100 hip arthroscopies per year are DDE 8.75 mrem (0.0875 mSv), LDE 8.75 mrem (0.0875 mSv), and SDE 8.43 mrem (0.0842 mSv). Conclusion: Hip arthroscopy & hip preservation procedures are being performed with increasing frequency annually. Fluoroscopic guidance is recommended for safe entrance into the central compartment and during various parts of the procedures. Radiation exposure to the surgeon, staff, and patient is a valid concern. The IRCP sets recommended annual safety thresholds for occupational radiation exposure. Current annual safety thresholds are 50,000 mrem (500 mSv) to the hands, 50,000 mrem (500 mSv) to the skin, hands & feet, 15,000 mrem (150 mSv) to the eye, and 30,000 mrem (300 mSv) to the thyroid of healthcare workers. Our study shows surgeon radiation exposure below the annual safety thresholds recommended by the IRCP for 100 cases per year. For surgeons performing more than 100 hip arthroscopic procedures annually, the exposure will be higher. Appropriate safety equipment such as lead aprons, thyroid shields, and leaded glasses are still recommended, especially for high volume hip arthroscopists. © The Author(s) 2015

Performance Analysis and Design of Maximum Ratio Combining in Channel-Aware MIMO Decision Fusion

In this paper we present a theoretical performance analysis of the maximum ratio combining (MRC) rule for channel-aware decision fusion over multiple-input multiple-output (MIMO) channels for (conditionally) dependent and independent local decisions. The system probabilities of false alarm and detection conditioned on the channel realization are derived in closed form and an approximated threshold choice is given. Furthermore, the channel-averaged (CA) performances are evaluated in terms of the CA system probabilities of false alarm and detection and the area under the receiver operating characteristic (ROC) through the closed form of the conditional moment generating function (MGF) of the MRC statistic, along with Gauss-Chebyshev (GC) quadrature rules. Furthermore, we derive the deflection coefficients in closed form, which are used for sensor threshold design. Finally, all the results are confirmed through Monte Carlo simulations.Comment: To appear in IEEE Transactions on Wireless Communication

The Transversity Function and Double Spin Azimuthal Asymmetry in Semi-Inclusive Pion Leptoproduction

We show that the transverse momentum dependent transversity function is proportional to the longitudinal polarization of a quark in a transversely polarized proton. This result suggests an alternative, convenient method for determining transversity, without knowing unusual fragmentation functions. The method consists of measuring the double spin azimuthal asymmetry in semi-inclusive pion leptoproduction by a transversely polarized proton target. The asymmetry, which is twist 3, is estimated to be more than 10% under the most favorable conditions. The experiment we suggest is feasible at facilities like DESY and CERN.Comment: extended version; to appear on Int. Jou. Mod. Phys.

POTENTIAL DEMAND AND PRELIMINARY DESIGN OF DOOR TO DOOR DIAL A RYDE SYSTEMS

The paper aims to provide a framework for the preliminary design of dial a ride system. In this context we have carried out a stated preference survey to evaluate the potential demand of service, taking into account a sample of citizens with limited disability to move. Thus, we have submitted a questionnaire to users of some clinics of Palermo, considering in the choice competitive scenario the dial a ride system. Furthermore a multinomial logit model has been calibrated. Finally a preliminary design of service has been proposed

Educational strategies in data journalism: A comparative study of six European countries

The article explores training programs in higher education with regard to data journalism from a multi-national perspective. By carrying out a comparative analysis in six European countries (Germany, Switzerland, the Netherlands, Italy, Poland, and the United Kingdom), it covers different models of media systems and journalistic cultures envisaged by Hallin and Mancini. Based on a desk review and in-depth interviews with instructors of data journalism in each country, the article identifies different approaches to the way data journalism is taught. In Europe, such programs are offered by four types of organizations: academic, vocational, professional, and civic. The role played by those organizations can be explained as a result of the peculiarities of national media systems. But there are also commonalities, for example, non-academic institutions (such as the European Journalism Center or the Center for Investigative Journalism) and major international news outlets (such as The Guardian and The New York Times) seem to take over a leading role in all of the analyzed countries. Generally speaking, data journalism education appears to be a very young discipline that frequently neglects fundamental journalistic topics such as ethical issues, transparency, accountability, and responsiveness although they are crucial in a journalistic field as sophisticated tools to reveal hidden aspects of reality

Broad-band Spectral Evolution of Scorpius X-1 along its Color-Color Diagram

We analyze a large collection of RXTE archive data from April 1997 to August 2003 of the bright X-ray source Scorpius X-1 in order to study the broadband spectral evolution of the source for different values of the inferred mass accretion rate by studying energy spectra from selected regions in the Z-track of its Color-Color Diagram. A two-component model, consisting of a soft thermal component interpreted as thermal emission from an accretion disk and a thermal Comptonization component, is unable to fit the whole 3--200 keV energy spectrum at low accretion rates. Strong residuals in the highest energy band of the spectrum require the addition of a third component that can be fitted with a power-law component, that could represent a second thermal Comptonization from a much hotter plasma, or a hybrid thermal/non-thermal Comptonization. We discuss the physical implications derived from the results of our analysis, with a particular emphasis on the hardest part of the X-ray emission and its possible origins.Comment: 18 pages. Accepted for publication in Ap

Growing Pains or Opportunities? A Customer Survey of Three Farmers\u27 Markets in One Rural Community

The continued growth of farmers\u27 markets is presenting new challenges to Extension. As the number of markets expands, how can Extension help those in the same community work together for mutual benefit? The study reported here examined similarities and differences among customers attending three different farmers\u27 markets within a single locality in Gettysburg, Pennsylvania. Based on 370 customer surveys, study results underscore the diversity of markets operating within the same community and provide insights into ways Extension might assist markets to work together to expand their shared customer base, increase revenues, and better serve local residents