262 research outputs found

    Risk of basal cell carcinoma after Hodgkin's disease

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    Background: Basal cell cancer is a common skin cancer, yet studies of second tumors after Hodgkin's disease tend to exclude basal cell cancers as second malignant tumors from analysis. Basal cell carcinomas (BCC) are possibly more common in immunosuppressed patients and were recently implicated as indicators of subsequent malignancies. Materials and Methods: Our database of 1,120 patients with Hodgkin's disease (derived from the tumor registry) was investigated for the occurrence of later BCCs. Kaplan-Meier curves were calculated. Results: A total of 9 cases of BCC were observed 0-20 years after the diagnosis of Hodgkin's disease, One case relapsed after excision. The probability of second BCC was 2.1% after 15 years of follow-up and 7.1% after 20 years. Statistically, the risk for second BCC was increased only in younger patients and with prolonged follow-up, but not in the total group of patients with Hodgkin's disease. Conclusion: BCC is not a major threat: for the survivors of Hodgkin's disease, but continued follow-up is necessary

    Advanced head and neck cancer: Long-term results of chemo-radiotherapy, complications and induction of second malignancies

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    Background: Chemo-radiotherapy is superior to radiotherapy alone in the treatment of advanced, inoperable head and neck cancer. The long-term treatment results, the induction of second malignant tumors, and other long-term toxicities are not well defined. Patients and Methods: 100 consecutive patients with advanced head and neck cancer who were treated at our center were studied. Treatment results, survival, the occurrence of late complications, and second malignant tumors (SMT) were investigated. 78 patients were treated with a protocol combining cisplatinum, 5-fluorouracil, folinic acid and hyper-fractionated irradiation. 22 patients were treated with other chemo-radiotherapy protocols. The relative risk of developing an SMT was compared with that within the normal population. Results: The cumulative total probability of survival was 51.1% at 2 years and 38.7% at 4 years. The probability of relapse-free survival was 39.9% at 2 years and 36.7% at 4 years. A total of 7 patients developed SMT (4 cases of lung cancer, 2 colon cancers, 1 skin cancer). After 6 years, a cumulative risk of SMT of 8.7% was observed. The relative risk of developing an SMT was significantly increased (4.45-fold in males) compared with a normal population. 13 of 38 evaluable patients (34.2%) had severe late complications like fibrosis of soft tissues, nerve lesions, or were dependent on tracheal cannulas. Conclusions: The treatment results and long-term prognoses in our population of unselected high-risk patients are unsatisfactory, but comparable to those from multicenter studies. About 35% of patients become long-term (> 4 years) survivors. SMT generally occur early, have a poor prognosis and, most likely, are not treatment-related. Approximately 30% of long-term survivors have severe, often incapacitating late effects. The treatment and - if possible - prevention of these late effects is important for the quality of life of patients who survived advanced head and neck cancer

    CliCTD: A monolithic HR-CMOS sensor chip for the CLIC silicon tracker

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    The CLIC Tracker Detector (CLICTD) is a monolithic pixelated sensor chip produced in a 180 nm imaging CMOS process built on a high-resistivity epitaxial layer. The chip, designed in the context of the CLIC tracking detector study, comprises a matrix of 16 x 128 elongated pixels, each measuring 300 x 30 μm2^{2}. To ensure prompt charge collection, every elongated pixel is segmented in eight sub-pixels, each containing a collection diode and a separate analog front-end. A simultaneous 8-bit time measurement with 10 ns time bins and 5-bit energy measurement with programmable range is performed in the on-pixel digital logic. The main design aspects as well as the first results from laboratory measurements with the CLICTD chip are presented

    Von Bezold assimilation effect reverses in stereoscopic conditions

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    Lightness contrast and lightness assimilation are opposite phenomena: in contrast, grey targets appear darker when bordering bright surfaces (inducers) rather than dark ones; in assimilation, the opposite occurs. The question is: which visual process favours the occurrence of one phenomenon over the other? Researchers provided three answers to this question. The first asserts that both phenomena are caused by peripheral processes; the second attributes their occurrence to central processes; and the third claims that contrast involves central processes, whilst assimilation involves peripheral ones. To test these hypotheses, an experiment on an IT system equipped with goggles for stereo vision was run. Observers were asked to evaluate the lightness of a grey target, and two variables were systematically manipulated: (i) the apparent distance of the inducers; and (ii) brightness of the inducers. The retinal stimulation was kept constant throughout, so that the peripheral processes remained the same. The results show that the lightness of the target depends on both variables. As the retinal stimulation was kept constant, we conclude that central mechanisms are involved in both lightness contrast and lightness assimilation

    Combining TCAD and Monte Carlo methods to simulate CMOS pixel sensors with a small collection electrode using the Allpix2^{2} framework

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    Combining electrostatic field simulations with Monte Carlo methods enables realistic modeling of the detector response for novel monolithic silicon detectors with strongly non-linear electric fields. Both the precise field description and the inclusion of Landau fluctuations and production of secondary particles in the sensor are crucial ingredients for the understanding and reproduction of detector characteristics. In this paper, a CMOS pixel sensor with small collection electrode design, implemented in a high-resistivity epitaxial layer, is simulated by integrating a detailed electric field model from finite element TCAD into a Monte Carlo based simulation with the framework. The simulation results are compared to data recorded in test-beam measurements and very good agreement is found for various quantities such as cluster size, spatial resolution and efficiency. Furthermore, the observables are studied as a function of the intra-pixel incidence position to enable a detailed comparison with the detector behavior observed in data. The validation of such simulations is fundamental for modeling the detector response and for predicting the performance of future prototype designs. Moreover, visualization plots extracted from the charge carrier drift model of the framework can aid in understanding the charge propagation behavior in different regions of the sensor

    Performance evaluation of thin active-edge planar sensors for the CLIC vertex detector

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    Thin planar silicon sensors with a pitch of 55μm, active edge and various guard-ring layouts are investigated,using two-dimensional finite-element T-CAD simulations. The simulation results have been compared toexperimental data, and an overall good agreement is observed. It is demonstrated that the 50μm thick active-edge planar silicon sensors with floating guard-ring or without guard-ring can be operated fully efficiently upto the physical edge of the sensor. The simulation findings are used to identify suitable sensor designs forapplication in the high-precision vertex detector of the future CLIC linear e+^{+}e^{-} collider

    Time resolution studies of Timepix3 assemblies with thin silicon pixel sensors

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    Timepix3 is a multi-purpose readout ASIC for hybrid pixel detectors. It can measure time and amplitude simultaneously by employing time-of-arrival (ToA) and time-over-threshold (ToT) techniques. Both methods are systematically affected by timewalk. In this paper, a method for pixel-by-pixel calibration of the time response is presented. Assemblies of Timepix3 ASICs bump-bonded to thin planar silicon pixel sensors with thicknesses of 50 μ m, 100 μ m and 150 μ m are calibrated and characterised in particle beams. For minimum ionising particles, time resolutions down to 0.72 ± 0.04 ns are achieved

    A new concurrent chemotherapy with vinorelbine and mitomycin C in combination with radiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck

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    Objective: The purpose of this pilot study was to evaluate the feasibility and toxicity of concurrent chemotherapy with vinorelbine and mitomycin C in combination with accelerated radiotherapy (RT) in patients with locally advanced cancer of the head and neck. Patients and Methods: Between January 2003 and March 2004, 15 patients with T4/N2-3 squamous cell carcinoma (12/15) and with N3 cervical lymph node metastases of carcinoma of unknown primary (3/15) were treated with chemotherapy and simultaneous accelerated RT. Results: 11 patients completed therapy without interruption or dose reduction. Grade 3 - 4 acute mucosal toxicity was observed in 9/15 patients, grade 4 hematologic toxicity in 6/15 patients. At a median follow-up of 7.5 months, 2 patients have died of intercurrent disease, 2 patients have experienced local relapse; 5 patients are alive with no evidence of disease at the primary tumor site. Discussion: The described regimen is highly effective, but led to remarkable side effects
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