Brachytherapy with ¹⁰⁶Ru eye plaques is the most common treatment modality for small to medium-sized uveal melanomas in Europe. So far, no standardized or widely accepted dose prescription protocol for the irradiation of intraocular tumors with ¹⁰⁶Ru eye plaques has been defined. For ¹²⁵I plaques, the minimum dose required for tumor control should be at least 85 Gy. Concerning ¹⁰⁶Ru plaques, the dose prescriptions at the University Hospital of Essen foresees minimum doses of 700 Gy to the tumor base and 130 Gy to the tumor apex. These dose prescriptions are expected to ensure sufficient treatment margins. We apply these dose prescriptions to different eye plaque types and tumor sizes and discuss the resulting treatment margins. These investigations are based on Monte Carlo simulations of dose distributions of 3 different eye plaque types. The treatment margin in apical direction has an expansion of at least 0.8 mm for all investigated eye plaques. For symmetrically formed eye plaques, the treatment margin at the base of the tumor goes beyond the visible edge of the plaque. This study focuses on the shape of 85-Gy isodose lines and on treatment margins for different eye plaque types and tumor sizes and shall help exchange knowledge for ocular brachytherapy.

The energy response was quantified relative to the response to (60)Co which is the common radiation quality for the calibration of therapy dosemeters. The observed energy dependence could be well explained with the assumption of ionization quenching as described by Birks' formula. Plastic scintillation detectors should be calibrated at the same radiation quality that they will be used at and changes of the spectrum within the application need to be considered. The authors results can be used to evaluate the range of validity of a given calibration.

Previous studies show remarkable differences in the simulation of electron depth dose profiles of ruthenium eye plaques. We examined the influence of the scoring and simulation geometry, the source spectrum and the multiple scattering algorithm on the depth dose profile using GEANT4. The simulated absolute dose deposition agrees with absolute dose data from the manufacturer within the measurement uncertainty. Variations in the simulation geometry as well as the source spectrum have only a small influence on the depth dose profiles. However, the multiple scattering algorithms have the largest influence on the depth dose profiles. They deposit up to 20% less dose compared to the single scattering implementation. We recommend researchers who are interested in simulating low- to medium-energy electrons to examine their simulation under the influence of different multiple scattering settings. Since the simulation and scoring geometry as well as the exact physics settings are best described by the source code of the application, we made the code publicly available.

Thromboembolien in der Schwangerschaft und in der frühen postpartalen Phase gehören in den westeuropäischen Staaten zu den Hauptursachen mütterlicher Morbidität und Mortalität [5,13,18, 20]. Aussagen zur Inzidenz dieser schwer wiegenden Erkrankung während der Schwangerschaft variieren zwischen 0,013 und 0,3%, hierbei wird die Letalität infolge einer Lungenembolie mit 1 pro 100 000 Schwangerschaften angegeben [6]. Wir beschreiben den Verlauf einer fulminanten Lungenembolie bei einer 35-jährigen Drittgebärenden unter der Geburt mit nachfolgender Notsectio und Lysetherapie. Zusammenfassung Eine 35-jährige Patientin erlitt unter der Geburt nach einer unauffällig verlaufenden Schwangerschaft eine fulminante Lungenarterienembolie mit darauf folgender Notsectio. Bei instabilen Kreislaufverhältnissen wurde ohne bildgebende Diagnostik eine Lysetherapie mit rt-PA durchgeführt. Nach Massentransfusion und Hysterektomie konnte die Patientin ohne Folgeschäden mit ihrem gesunden Säugling nach 24 Tagen Krankenhausaufenthalt entlassen werden. Die Schwangerschaft und ein diskretes Distorsionstrauma sind im vorliegenden Fall wahrscheinlich Auslöser der fulminanten Lungenembolie gewesen.

The challenge in rendering integral images is to use as much information preserved by the light field as possible to reconstruct a captured scene in a three-dimensional way. We propose a rendering algorithm based on the projection of rays through a detailed simulation of the optical path, considering all the physical properties and locations of the optical elements. The rendered images contain information about the correct size of imaged objects without the need to calibrate the imaging device. Additionally, aberrations of the optical system may be corrected, depending on the setup of the integral imaging device. We show simulation data that illustrates the aberration correction ability and experimental data from our plenoptic camera, which illustrates the capability of our proposed algorithm to measure size and distance. We believe this rendering procedure will be useful in the future for three-dimensional ophthalmic imaging of the human retina.