Validation of the Swiss Monte Carlo Plan for a static and dynamic 6 MV photon beam

Monte Carlo (MC) based dose calculations can compute dose distributions with an accuracy surpassing that of conventional algorithms used in radiotherapy, especially in regions of tissue inhomogeneities and surface discontinuities. The Swiss Monte Carlo Plan (SMCP) is a GUI-based framework for photon MC treatment planning (MCTP) interfaced to the Eclipse treatment planning system (TPS). As for any dose calculation algorithm, also the MCTP needs to be commissioned and validated before using the algorithm for clinical cases. Aim of this study is the investigation of a 6 MV beam for clinical situations within the framework of the SMCP. In this respect, all parts i.e. open fields and all the clinically available beam modifiers have to be configured so that the calculated dose distributions match the corresponding measurements. Dose distributions for the 6 MV beam were simulated in a water phantom using a phase space source above the beam modifiers. The VMC++ code was used for the radiation transport through the beam modifiers (jaws, wedges, block and multileaf collimator (MLC)) as well as for the calculation of the dose distributions within the phantom. The voxel size of the dose distributions was 2mm in all directions. The statistical uncertainty of the calculated dose distributions was below 0.4%. Simulated depth dose curves and dose profiles in terms of [Gy/MU] for static and dynamic fields were compared with the corresponding measurements using dose difference and γ analysis. For the dose difference criterion of ±1% of D(max) and the distance to agreement criterion of ±1 mm, the γ analysis showed an excellent agreement between measurements and simulations for all static open and MLC fields. The tuning of the density and the thickness for all hard wedges lead to an agreement with the corresponding measurements within 1% or 1mm. Similar results have been achieved for the block. For the validation of the tuned hard wedges, a very good agreement between calculated and measured dose distributions was achieved using a 1%/1mm criteria for the γ analysis. The calculated dose distributions of the enhanced dynamic wedges (10°, 15°, 20°, 25°, 30°, 45° and 60°) met the criteria of 1%/1mm when compared with the measurements for all situations considered. For the IMRT fields all compared measured dose values agreed with the calculated dose values within a 2% dose difference or within 1 mm distance. The SMCP has been successfully validated for a static and dynamic 6 MV photon beam, thus resulting in accurate dose calculations suitable for applications in clinical cases.

Improvement of physical and mental health after transfemoral transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) has emerged as a treatment alternative to surgical aortic valve replacement in elderly high-risk patients with symptomatic severe aortic stenosis. In this patient population, rapid improvement or restoration of quality of life (QoL) is at least as important as improved clinical outcomes. The purpose of the present study was to assess changes in QoL in response to TAVI.

Comparison of tendency-oriented perimetry and dynamic strategy in octopus perimetry as a screening tool in a clinical setting: a prospective study

OBJECTIVE: The aim of this study was to compare the results of tendency-oriented perimetry (TOP) and a dynamic strategy in octopus perimetry as screening methods in clinical practice. DESIGN: A prospective single centre observational case series was performed. PARTICIPANTS AND METHODS: In a newly opened general ophthalmologic practice 89 consecutive patients (171 eyes) with a clinical indication for octopus static perimetry testing (ocular hypertension or suspicious optic nerve cupping) were examined prospectively with TOP and a dynamic strategy. The visual fields were graded by 3 masked observers as normal, borderline or abnormal without any further clinical information. RESULTS: 83% eyes showed the same result for both strategies. In 14% there was a small difference (with one visual field being abnormal or normal, the other being borderline). In only 2.9% of the eyes (5 cases) was there a contradictory result. In 4 out of 5 cases the dynamic visual field was abnormal and TOP was normal. 4 of these cases came back for a second examination. In all 4 the follow-up examination showed a normal second dynamic visual field. CONCLUSIONS: Octopus static perimetry using a TOP strategy is a fast, patient-friendly and very reliable screening tool for the general ophthalmological practice. We found no false-negative results in our series.

[Physical and psychological status of 60-70-year-old citizens of Bern with neurotic symptoms in childhood--a study over more than 50 years (Emmental cohort)]

The present study was undertaken to assess the influence of childhood variables (physical and emotional) to later well-being in a group of rural Swiss (Emmental Cohort). Our study is the first prospective cohort over a time period of more than 50 years. It includes 1537 children who were listed and assessed in 1942 (T1) because they had difficulties in school or were otherwise behaviorally disturbed. In 1995 (T2) more than 60% of the initial population could be reassessed by our study group. We found more subjects at T2 who had been rated as intelligent at T1. More subjects responding to T2 belonged to a higher social class, were more anxious, and had more psychosocial problems at T1. Social income at T2 is correlated to the social class at T1. More subjects have died since who were rated at T1 as being less intelligent, less neurotical, and having higher psychosocial problems. Twice as many men died than women. The emotional situation at T2 is significantly correlated to psychological well-being at T1. The somatic complaints at T2 correlate significantly to neurotic symptoms in childhood (T1). The more intelligent the children were rated at T1, the less emotional and somatic complaints were voiced at T2 and the better the psychic well-being was rated (T2). In addition, the former social milieu (T1) significantly determined somatic and psychological complaints at T2. Our data discern a significant correlation between actual status and former childhood variables more than 50 years later in a rural Swiss cohort (Emmental Cohort).

Evaluation of physical and mental recovery status after elective liver resection

BACKGROUND AND OBJECTIVE: This prospective, clinical pilot trial compared the Short Form 36 Health Survey (SF-36) and a nine-item quality of recovery [Quality of Recovery 9 (QoR-9)] survey to assess the 1-week outcome after liver resection and prediction of postoperative complications from baseline values before liver resection. METHODS: In 19 patients, the SF-36 was recorded preoperatively (baseline) and on postoperative day (POD) 7. SF-36 z-values (means +/- SD) for the physical component summary (PCS) and mental component summary (MCS) were calculated. QoR-9 (score 0-18) was performed at baseline, POD1, POD3, POD5 and POD7. Descriptive analysis and effect sizes (d) were calculated. RESULTS: From baseline to POD7, PCS decreased from -0.38 +/- 1.30 to -2.10 +/- 0.76 (P = 0.002, d = -1.57) and MCS from -0.71 +/- 1.50 to -1.33 +/- 1.11 (P = 0.061, d = -0.46). QoR-9 was significantly lower at POD1, POD3 and POD5 compared with baseline (P < 0.050, d < -2.0), but not at POD7 (P = 0.060, d = -1.08). Baseline PCS was significantly lower with a high effect size in patients with complications (n = 12) compared with patients without complications (n = 7) (-0.76 +/- 1.46 vs. 0.27 +/- 0.56; P = 0.044, d = -0.84) but not baseline MCS (P = 0.831, d = -0.10) or baseline QoR-9 (P = 0.384, d = -0.44). CONCLUSIONS: The SF-36 indicates that liver resection surgery has a higher impact on physical health than on mental health. QoR-9 determines the feasible time course of recovery with a 1-week return to baseline. Preoperative impaired physical health might predict postoperative complications.

Impacts of changing climate and land use on vegetation dynamics in a Mediterranean ecosystem: insights from paleoecology and dynamic modeling

Forests near the Mediterranean coast have been shaped by millennia of human disturbance. Consequently, ecological studies relying on modern observations or historical records may have difficulty assessing natural vegetation dynamics under current and future climate. We combined a sedimentary pollen record from Lago di Massacciucoli, Tuscany, Italy with simulations from the LandClim dynamic vegetation model to determine what vegetation preceded intense human disturbance, how past changes in vegetation relate to fire and browsing, and the potential of an extinct vegetation type under present climate. We simulated vegetation dynamics near Lago di Massaciucoli for the last 7,000 years using a local chironomid-inferred temperature reconstruction with combinations of three fire regimes (small infrequent, large infrequent, small frequent) and three browsing intensities (no browsing, light browsing, and moderate browsing), and compared model output to pollen data. Simulations with low disturbance support pollen-inferred evidence for a mixed forest dominated by Quercus ilex (a Mediterranean species) and Abies alba (a montane species). Whereas pollen data record the collapse of A. alba after 6000 cal yr bp, simulated populations expanded with declining summer temperatures during the late Holocene. Simulations with increased fire and browsing are consistent with evidence for expansion by deciduous species after A. alba collapsed. According to our combined paleo-environmental and modeling evidence, mixed Q. ilex and A. alba forests remain possible with current climate and limited disturbance, and provide a viable management objective for ecosystems near the Mediterranean coast and in regions that are expected to experience a mediterranean-type climate in the future.