The cyclotron laboratory and the RFQ accelerator in Bern

Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: a proof of concept.

PURPOSE External beam radiation therapy is currently considered the most common treatment modality for intraocular tumors. Localization of the tumor and efficient compensation of tumor misalignment with respect to the radiation beam are crucial. According to the state of the art procedure, localization of the target volume is indirectly performed by the invasive surgical implantation of radiopaque clips or is limited to positioning the head using stereoscopic radiographies. This work represents a proof-of-concept for direct and noninvasive tumor referencing based on anterior eye topography acquired using optical coherence tomography (OCT). METHODS A prototype of a head-mounted device has been developed for automatic monitoring of tumor position and orientation in the isocentric reference frame for LINAC based treatment of intraocular tumors. Noninvasive tumor referencing is performed with six degrees of freedom based on anterior eye topography acquired using OCT and registration of a statistical eye model. The proposed prototype was tested based on enucleated pig eyes and registration accuracy was measured by comparison of the resulting transformation with tilt and torsion angles manually induced using a custom-made test bench. RESULTS Validation based on 12 enucleated pig eyes revealed an overall average registration error of 0.26 ± 0.08° in 87 ± 0.7 ms for tilting and 0.52 ± 0.03° in 94 ± 1.4 ms for torsion. Furthermore, dependency of sampling density on mean registration error was quantitatively assessed. CONCLUSIONS The tumor referencing method presented in combination with the statistical eye model introduced in the past has the potential to enable noninvasive treatment and may improve quality, efficacy, and flexibility of external beam radiotherapy of intraocular tumors.

Monte Carlo based beam model using a photon MLC for modulated electron radiotherapy

PURPOSE Modulated electron radiotherapy (MERT) promises sparing of organs at risk for certain tumor sites. Any implementation of MERT treatment planning requires an accurate beam model. The aim of this work is the development of a beam model which reconstructs electron fields shaped using the Millennium photon multileaf collimator (MLC) (Varian Medical Systems, Inc., Palo Alto, CA) for a Varian linear accelerator (linac). METHODS This beam model is divided into an analytical part (two photon and two electron sources) and a Monte Carlo (MC) transport through the MLC. For dose calculation purposes the beam model has been coupled with a macro MC dose calculation algorithm. The commissioning process requires a set of measurements and precalculated MC input. The beam model has been commissioned at a source to surface distance of 70 cm for a Clinac 23EX (Varian Medical Systems, Inc., Palo Alto, CA) and a TrueBeam linac (Varian Medical Systems, Inc., Palo Alto, CA). For validation purposes, measured and calculated depth dose curves and dose profiles are compared for four different MLC shaped electron fields and all available energies. Furthermore, a measured two-dimensional dose distribution for patched segments consisting of three 18 MeV segments, three 12 MeV segments, and a 9 MeV segment is compared with corresponding dose calculations. Finally, measured and calculated two-dimensional dose distributions are compared for a circular segment encompassed with a C-shaped segment. RESULTS For 15 × 34, 5 × 5, and 2 × 2 cm(2) fields differences between water phantom measurements and calculations using the beam model coupled with the macro MC dose calculation algorithm are generally within 2% of the maximal dose value or 2 mm distance to agreement (DTA) for all electron beam energies. For a more complex MLC pattern, differences between measurements and calculations are generally within 3% of the maximal dose value or 3 mm DTA for all electron beam energies. For the two-dimensional dose comparisons, the differences between calculations and measurements are generally within 2% of the maximal dose value or 2 mm DTA. CONCLUSIONS The results of the dose comparisons suggest that the developed beam model is suitable to accurately reconstruct photon MLC shaped electron beams for a Clinac 23EX and a TrueBeam linac. Hence, in future work the beam model will be utilized to investigate the possibilities of MERT using the photon MLC to shape electron beams.

Sleepiness and performance is disproportionate in patients with non-organic hypersomnia in comparison to patients with narcolepsy and mild to moderate obstructive sleep apnoea.

BACKGROUND/AIMS Clinical differentiation between organic hypersomnia and non-organic hypersomnia (NOH) is challenging. We aimed to determine the diagnostic value of sleepiness and performance tests in patients with excessive daytime sleepiness (EDS) of organic and non-organic origin. METHODS We conducted a retrospective comparison of the multiple sleep latency test (MSLT), pupillography, and the Steer Clear performance test in three patient groups complaining of EDS: 19 patients with NOH, 23 patients with narcolepsy (NAR), and 46 patients with mild to moderate obstructive sleep apnoea syndrome (OSAS). RESULTS As required by the inclusion criteria, all patients had Epworth Sleepiness Scale (ESS) scores >10. The mean sleep latency in the MSLT indicated mild objective sleepiness in NOH (8.1 ± 4.0 min) and OSAS (7.2 ± 4.1 min), but more severe sleepiness in NAR (2.5 ± 2.0 min). The difference between NAR and the other two groups was significant; the difference between NOH and OSAS was not. In the Steer Clear performance test, NOH patients performed worst (error rate = 10.4%) followed by NAR (8.0%) and OSAS patients (5.9%; p = 0.008). The difference between OSAS and the other two groups was significant, but not between NOH and NAR. The pupillary unrest index was found to be highest in NAR (11.5) followed by NOH (9.2) and OSAS (7.4; n.s.). CONCLUSION A high error rate in the Steer Clear performance test along with mild sleepiness in an objective sleepiness test (MSLT) in a patient with subjective sleepiness (ESS) is suggestive of NOH. This disproportionately high error rate in NOH may be caused by factors unrelated to sleep pressure, such as anergia, reduced attention and motivation affecting performance, but not conventional sleepiness measurements.

Adaptive servo-ventilation as treatment of persistent central sleep apnea in post-acute ischemic stroke patients.

BACKGROUND Adaptive servo-ventilation (ASV) is a well-established treatment of central sleep apnea (CSA) related to congestive heart failure (CHF). Few studies have evaluated the effectiveness and adherence in patients with CSA of other etiologies, and even less is known about treatment of CSA in patients of post ischemic stroke. METHODS A single-centre retrospective analysis of ASV treatment for CSA in post-acute ischemic stroke patients without concomitant CHF was performed. Demographics, clinical data, sleep studies, ventilator settings, and adherence data were evaluated. RESULTS Out of 154 patients on ASV, 15 patients had CSA related to ischemic stroke and were started on ASV a median of 11 months after the acute cerebrovascular event. Thirteen out of the 15 patients were initially treated with continuous positive airway pressure (11/15) and bilevel positive airway pressure (2/15) therapy with unsatisfactory control of CSA. ASV significantly improved AHI (46.7 ± 24.3 vs 8.5 ± 12/h, P = 0.001) and reduced ESS (8.7 ± 5.7 vs 5.6 ± 2.5, P = 0.08) with a mean nightly use of ASV of 5.4 ± 2.4 h at 3 months after the initiation of treatment. Results were maintained at 6 months. CONCLUSION ASV was well tolerated and clinically effective in this group of patients with persistent CSA after ischemic stroke.

Breast cancer in younger women in Switzerland 1996-2009: A longitudinal population-based study.

BACKGROUND Breast cancer (BC) is the most commonly diagnosed cancer and a leading cause of death in younger women. METHODS We analysed incidence, mortality and relative survival (RS) in women with BC aged 20-49 years at diagnosis, between 1996 and 2009 in Switzerland. Trends are reported as estimated annual percentage changes (EAPC). RESULTS Our findings confirm a slight increase in the incidence of BC in younger Swiss women during the period 1996-2009. The increase was largest in women aged 20-39 years (EAPC 1.8%). Mortality decreased in both age groups with similar EAPCs. Survival was lowest among women 20-39 years (10-year RS 73.4%). We observed no notable differences in stage of disease at diagnosis that might explain these differences. CONCLUSIONS The increased incidence and lower survival in younger women diagnosed with BC in Switzerland indicates possible differences in risk factors, tumour biology and treatment characteristics that require additional examination.

Impact of local endothelial shear stress on neointima and plaque following stent implantation in patients with ST-elevation myocardial infarction: A subgroup-analysis of the COMFORTABLE AMI-IBIS 4 trial.

BACKGROUND Numerous studies have demonstrated an association between endothelial shear stress (ESS) and neointimal formation after stent implantation. However, the role of ESS on the composition of neointima and underlying plaque remains unclear. METHODS Patients recruited in the Comfortable AMI-IBIS 4 study implanted with bare metal stents (BMS) or biolimus eluting stents (BES) that had biplane coronary angiography at 13month follow-up were included in the analysis. The intravascular ultrasound virtual-histology (IVUS-VH) and the angiographic data were used to reconstruct the luminal surface, and the stent in the stented segments. Blood flow simulation was performed in the stent surface, which was assumed to represent the luminal surface at baseline, to assess the association between ESS and neointima thickness. The predominant ESS was estimated in 3-mm segments and was correlated with the amount of neointima, neointimal tissue composition, and with the changes in the underlying plaque burden and composition. RESULTS Forty three patients (18 implanted with BMS and 25 with BES) were studied. In both stent groups negative correlations were noted between ESS and neointima thickness in BMS (P<0.001) and BES (P=0.002). In BMS there was a negative correlation between predominant ESS and the percentage of the neointimal necrotic core component (P=0.015). In BES group, the limited neointima formation did not allow evaluation of the effect of ESS on its tissue characteristics. ESS did not affect vessel wall remodeling and the plaque burden and composition behind BMS (P>0.10) and BES (P>0.45). CONCLUSIONS ESS determines neointimal formation in both BMS and BES and affects the composition of the neointima in BMS. Conversely, ESS does not impact the plaque behind struts irrespective of stent type throughout 13months of follow-up.

Lung cancer in the Canton of St. Gallen, Eastern Switzerland: sex-associated differences in smoking habits, disease presentation and survival.

BACKGROUND The aim of this study was to assess sex-associated differences in lung cancer patients in Eastern Switzerland. METHODS All 670 lung cancer patients referred to the cancer center in St. Gallen between January 2000 and December 2005 were retrospectively analyzed. We investigated sex-associated differences in age, smoking habits, histology, stage, treatment and survival. RESULTS There were 474 (71%) men and 196 (29%) women with lung cancer. Mean age at the time of diagnosis was 64 years for women and 67 years for men (p = 0.01). Of the patients <55 years of age, 47 (24%) were women and only 65 (14%) were men. Men smoked significantly more than women (median pack-years: 50 vs. 30; p < 0.001). Of the heavy smokers (>40 pack-years), 278 (56%) were men and 68 (33%) were women. More men had squamous cell carcinoma (36%) than women (17%). Conversely, more women presented with adenocarcinoma (48%) than men (27%). No significant sex-associated differences were observed when analyzing first treatments received. Median overall survival was 10 months for both sexes. CONCLUSIONS In Eastern Switzerland, women with lung cancer were younger, more likely to have smoked significantly less and more likely to have adenocarcinoma, compared to men with lung cancer. These findings are consistent with those found in other western populations.

Ms. lat. qu. 60 - Expositio in epistolas Pauli

Vorbesitzer: Johann Ignaz von und zur Mühlen; Leander van Ess; Sir Thomas Phillipps

Territorio y economía plural : una aproximación al desarrollo

En la presente obra se abordan las diversas teorías que intentan explicar al “desarrollo", para luego profundizar en la economía plural. Esto se debe a la gran diversidad de situaciones referidas a las formas de hacer economía, las que coexisten y se manifiestan de distintas maneras en el territorio. En el marco de una economía de mercado, interpreta el comportamiento de las empresas y los particulares y el rol que cumple el Estado como regulador de las imperfecciones del mercado y promotor de la Economía Social y Solidaria (ESS). Se llega a la conclusión de que las estrategias implementadas están asociadas a políticas sociales focalizadas y asistenciales sin una clara forma de administración y control.

Educación transformadora : Una propuesta universitaria de inclusión educativa y articulación territorial en Economía Social y Solidaria

En esta ponencia pretendemos reflexionar en torno a la experiencia del DOSESS (Diploma de Operador Socioeducativo en Economía Social y Solidaria de la UNQ) en tanto proceso educativo alternativo a la educación formal y proceso de formación integral en ESS. Para lograr dicho objetivo, por un lado, buscaremos reflexionar en torno al rol de la Universidad en tanto agente de transformación territorial e inclusión educativa y, por otro lado, analizar las prácticas de educación popular y comunidad de aprendizaje como procesos educativos de inclusión y transformación social. A fin de abordar estas cuestiones y poder dar cuenta de las percepciones, representaciones y sentidos de los protagonistas de la experiencia, adoptamos una perspectiva metodológica de corte cualitativo, utilizando como herramientas centrales testimonios escritos y orales de los participantes del DOSESS, encuestas realizadas a los estudiantes, los informes de prácticas realizados, y las memorias de clases

Educación transformadora : Una propuesta universitaria de inclusión educativa y articulación territorial en Economía Social y Solidaria

En esta ponencia pretendemos reflexionar en torno a la experiencia del DOSESS (Diploma de Operador Socioeducativo en Economía Social y Solidaria de la UNQ) en tanto proceso educativo alternativo a la educación formal y proceso de formación integral en ESS. Para lograr dicho objetivo, por un lado, buscaremos reflexionar en torno al rol de la Universidad en tanto agente de transformación territorial e inclusión educativa y, por otro lado, analizar las prácticas de educación popular y comunidad de aprendizaje como procesos educativos de inclusión y transformación social. A fin de abordar estas cuestiones y poder dar cuenta de las percepciones, representaciones y sentidos de los protagonistas de la experiencia, adoptamos una perspectiva metodológica de corte cualitativo, utilizando como herramientas centrales testimonios escritos y orales de los participantes del DOSESS, encuestas realizadas a los estudiantes, los informes de prácticas realizados, y las memorias de clases

Taller de Química experimental : Una mirada más allá del tubo de ensayo

El taller consiste en una propuesta de trabajo grupal entre los alumnos y el coordinador docente en el que se emplean las metodologías que ayuden a aprender a pensar, aplicar conocimientos previamente adquiridos y descubrir nuevos. Es una propuesta abierta que conjuga trabajo con creatividad y cierta dosis lúdica, haciendo de la clase una experiencia activa donde se construye, intercambia y recrea con espacio para imaginar, equivocarse, ensayar, reflexionar. Así se desarrolló un taller optativo de Química Experimental con alumnos del 6º año del Ciclo ESS orientado en Ciencias Naturales. Se buscaron actividades donde los alumnos desarrollaran aspectos creativos sin perder de vista la adquisición y afianzamiento de conceptos abordados total o parcialmente en distintas asignaturas. Los temas seleccionados fueron: Metales y Corrosión; Colorantes: estructura e interacción con la luz, su obtención a partir de líquenes; Vitaminas: estructura y propiedades; Elaboración de productos cosméticos (jabones, champú, cremas); Esencias: obtención; Trabajo con polímeros sintéticos. El trabajo permitió sacar conclusiones críticas y enriquecedoras para alumnos y docentes.

Educación transformadora : Una propuesta universitaria de inclusión educativa y articulación territorial en Economía Social y Solidaria

En esta ponencia pretendemos reflexionar en torno a la experiencia del DOSESS (Diploma de Operador Socioeducativo en Economía Social y Solidaria de la UNQ) en tanto proceso educativo alternativo a la educación formal y proceso de formación integral en ESS. Para lograr dicho objetivo, por un lado, buscaremos reflexionar en torno al rol de la Universidad en tanto agente de transformación territorial e inclusión educativa y, por otro lado, analizar las prácticas de educación popular y comunidad de aprendizaje como procesos educativos de inclusión y transformación social. A fin de abordar estas cuestiones y poder dar cuenta de las percepciones, representaciones y sentidos de los protagonistas de la experiencia, adoptamos una perspectiva metodológica de corte cualitativo, utilizando como herramientas centrales testimonios escritos y orales de los participantes del DOSESS, encuestas realizadas a los estudiantes, los informes de prácticas realizados, y las memorias de clases

Taller de Química experimental : Una mirada más allá del tubo de ensayo

El taller consiste en una propuesta de trabajo grupal entre los alumnos y el coordinador docente en el que se emplean las metodologías que ayuden a aprender a pensar, aplicar conocimientos previamente adquiridos y descubrir nuevos. Es una propuesta abierta que conjuga trabajo con creatividad y cierta dosis lúdica, haciendo de la clase una experiencia activa donde se construye, intercambia y recrea con espacio para imaginar, equivocarse, ensayar, reflexionar. Así se desarrolló un taller optativo de Química Experimental con alumnos del 6º año del Ciclo ESS orientado en Ciencias Naturales. Se buscaron actividades donde los alumnos desarrollaran aspectos creativos sin perder de vista la adquisición y afianzamiento de conceptos abordados total o parcialmente en distintas asignaturas. Los temas seleccionados fueron: Metales y Corrosión; Colorantes: estructura e interacción con la luz, su obtención a partir de líquenes; Vitaminas: estructura y propiedades; Elaboración de productos cosméticos (jabones, champú, cremas); Esencias: obtención; Trabajo con polímeros sintéticos. El trabajo permitió sacar conclusiones críticas y enriquecedoras para alumnos y docentes.