[Radiation exposure of the eye lens in orthopedics and trauma surgery : A pilot study]. / Strahlenbelastung der Augenlinse in O&U : Eine Pilotstudie.

BACKGROUND: On 27 June 2017 the Act on new regulation of the law for the protection against the harmful effects of ionizing radiation was passed. One of the main innovations in daily surgical practice in the now legally stipulated provisions is the lowering of the eye lens dose to 20 mSv/year (§§ 78, 212 Radiation Protection Act, StrlSchG). MATERIAL AND METHODS: To estimate the level of exposure of the eye lens to ionizing radiation that is to be expected in the course of surgical interventions, the dose that surgeons receive during surgery was determined. For this, the radiation exposure adjacent to the eye lens was measured using a forehead dosimeter while performing surgical interventions over a period of 8 weeks in 2 different operating rooms. RESULTS: As a result, a mean estimated eye lens radiation dose Hp (3) of 190 µSv could be determined during the 2­month study period. Thus, the estimated cumulative radiation dose in 1 year of approximately 1.2 mSv was significantly below the threshold of 20 mSv/year. CONCLUSION: By complying with the common radiation protection measures in the context of operative interventions in orthopedics and trauma surgery, the legal limit value of 20 mSv/year is generally not expected to be exceeded.

[Effect of X-ray protective visors on the eye lens dose during ureteroscopy]. / Effekt von Strahlenschutzvisieren auf die Augenlinsendosis bei der Ureterorenoskopie.

BACKGROUND AND OBJECTIVES: Eye lens radiation exposure during fluoroscopy-guided interventional procedures may result in occupational radiation-induced cataracts. We evaluated the eye lens radiation doses and the protective effect of X­ray protective visors during ureteroscopic procedures. MATERIALS AND METHODS: Eye lens doses were measured in front of and behind X­ray protective visors using eye lens dosemeters during ureteroscopic procedures done by 4 different endourologic surgeons within a 12-week period. Background radiation dose, simultaneously measured with transport dosemeters, was subtracted. Measured eye lens doses below the detection limit of the eye lens dosemeters were adjusted to the detection limit of 0.028 mSv. Correlating the eye lens doses (ELD) to the dose-area-product (DAP) an ELD/DAP ratio was calculated. Applying this ELD/DAP ratio the potential reduction of the eye lens radiation dose was retrospectively calculated for all ureteroscopic procedures done within one year. RESULTS: Within the 12-week period 76 ureteroscopies were done by the 4 endourologic surgeons. The accumulated eye lens radiation dose was 0.796 mSv in front of the X­ray protective visors, and 0.338 mSv behind the X­ray protective visors. Thus, the eye lens radiation exposure was reduced to at least 42% by using X­ray protective visors. Considering the 215 documented ureteroscopies in our clinic in the year before starting the study, occupational radiation exposure to the eye lens would have been reduced by X­ray protective visors from 4.090 to 1.737 mSv. CONCLUSION: X­ray protective visors can effectively reduce the radiation exposure to the eye lens during fluoroscopy-guided endourologic procedures and should be used especially by high-volume endourologic surgeons.

INTERCOMPARISON OF EYE LENS DOSEMETERS.

An intercomparison of eye lens dosemeters has been conducted in terms of the quantity Hp(3). For the first time, besides photon radiation also beta radiation qualities were included. Three dosemeter types designed for the quantity Hp(3) and ten for Hp(0.07) took part in the intercomparison. As shown in a previous intercomparison for photon radiation only, the dosemeters designed for Hp(0.07) and calibrated in terms of Hp(3) performed well in photon radiation fields. But for beta radiation, it turned out that Hp(0.07) dosemeters over-responded up to a factor of 5 000 (with respect to the true Hp(3) dose) in the medium beta energy range (85Kr with a beta endpoint energy of 0.69 MeV), while some Hp(3) dosemeters performed quite well. For medium (57 keV) and high (662 keV) energy photon radiation, all dosemeter types showed response values well within the trumpet curve according to the current draft of ISO 14146.

PROPERTIES OF THE BEOSL DOSIMETRY SYSTEM IN THE FRAMEWORK OF A LARGE-SCALE PERSONAL MONITORING SERVICE.

The Individual Monitoring Service of the Helmholtz Zentrum München is currently using the BeOSL dosimetry system for monitoring ∼15 000 persons per month. This dosimetry system has a modular structure and represents a complete new concept on handling dosemeters in a large-scale dosimetry service. It is based on optically stimulated luminescence dosemeters made of beryllium oxide. The dosimetric and operational properties of the system are shown and discussed.

Using gaseous emissions of a proton accelerator facility as tracer for small-scale atmospheric dispersion.

The gaseous effluents of the proton accelerator facility located in the Western part of the Paul Scherrer Institute, Aargau, Switzerland, contain a mixture of positron emitters (50 % (15)O, 20 % (13)N and 30 % (11)C). For the experimental verification of a future upgrade of the dispersion model in the complex topography of the Aare valley, a measuring campaign using three continuous gamma-spectrometric measuring stations was launched in 2011. The concept of a modified man-made-gross-count (MMGC) ratio yields a clear signal associated with the positron emitters while minimising the influence of radon progeny rain-out events. A dependence of the measured MMGC ratios on the emitted activity and wind direction could be demonstrated using frequency distributions of the modified MMGC ratio measured in 2012 and 2013. A significant fraction of high MMGC-ratio values was found associated with dispersion directions (based on measurements of the wind direction in 70 m above ground) not towards or even against the direction between stack and measuring station.

Neutron dose rate at the SwissFEL injector test facility: first measurements.

At the Paul Scherrer Institute, the new SwissFEL Free Electron Laser facility is currently in the design phase. It is foreseen to accelerate electrons up to a maximum energy of 7 GeV with a pulsed time structure. An injector test facility is operated at a maximum energy of 300 MeV and serves as the principal test and demonstration plant for the SwissFEL project. Secondary radiation is created in unavoidable interactions of the primary beam with beamline components. The resulting ambient dose-equivalent rate due to neutrons was measured along the beamline with different commercially available survey instruments. The present study compares the readings of these neutron detectors (one of them is specifically designed for measurements in pulsed fields). The experiments were carried out in both, a normal and a diagnostic mode of operation of the injector.