Searching standard parameters for volumetric modulated arc therapy (VMAT) of prostate cancer

Background Since December 2009 a new VMAT planning system tool is available in Oncentra® MasterPlan v3.3 (Nucletron B.V.). The purpose of this study was to work out standard parameters for the optimization of prostate cancer. Methods For ten patients with localized prostate cancer plans for simultaneous integrated boost were optimized, varying systematically the number of arcs, collimator angle, the maximum delivery time, and the gantry spacing. Homogeneity in clinical target volume, minimum dose in planning target volume, median dose in the organs at risk, maximum dose in the posterior part of the rectum, and number of monitor units were evaluated using student’s test for statistical analysis. Measurements were performed with a 2D-array, taking the delivery time, and compared to the calculation by the gamma method. Results Plans with collimator 45° were superior to plans with collimator 0°. Single arc resulted in higher minimum dose in the planning target volume, but also higher dose values to the organs at risk, requiring less monitor units per fraction dose than dual arc. Single arc needs a higher value (per arc) for the maximum delivery time parameter than dual arc, but as only one arc is needed, the measured delivery time was shorter and stayed below 2.5 min versus 3 to 5 min. Balancing plan quality, dosimetric results and calculation time, a gantry spacing of 4° led to optimal results. Conclusion A set of parameters has been found which can be used as standard for volumetric modulated arc therapy planning of prostate cancer

Isolasi Dan Karakterisasi Bakteri Endofit Penghasil Inhibitor α-Glukosidase Dari Tanaman Pare (Momordica Charantia L)

Diabetes merupakan penyakit metabolik yang serius di Indonesia. Jumlah penderita diabetes mengalami peningkatan setiap tahunnya. Inhibitor α-glukosidase merupakan senyawa yang dapat menghambat enzim α-glukosidase sehingga bermanfaat sebagai obat antidiabetes. Tanaman Pare (Momordica charantia) diketahui memiliki kasiat sebagai anti diabetes. Senyawa aktif yang dihasilkan tanaman tersebut dapat berasal dari endofit yang hidup di dalam jaringan tanaman. Eksplorasi bakteri endofit dari tanaman pare merupakan salah satu cara untuk mendapatkan isolat bakteri penghasil inhibitor enzim α-glukosidase. Isolasi bakteri dilakukan dengan menginokulasikan sampel tanaman yang telah disterilisasi permukaan pada media agar. Isolat bakteri yang didapat selanjutnya dimurnikan dan di karakterisasi lebih lanjut baik morfologi maupun aktivitas inhibitor α-glukosidasenya. Pengujian aktivitas inhibitor α-glukosidase menggunakan metode spektrofotometer dengan nitrofenil-α-D-glukopiranosida sebagai substrat. Hasil penelitian diperoleh 5 isolat bakteri endofit penghasil inhibior α-glukosidase. Penghambatan terbesar ditunjukkan oleh isolat bakteri Ad 1 yaitu sebesar 27,4%

Fastrac Engine: Understanding Technical Implications of Programmatic Decisions

No abstract availabl

Gemcitabine and carboplatin in intensively pretreated patients with metastatic breast cancer

Background: Patients with metastatic breast cancer (MBC) are increasingly exposed to anthracyclines and taxanes either during treatment of primary breast cancer or during initial therapy of metastatic disease. The combination of gemcitabine and carboplatin was therefore investigated as an anthracycline- and taxane-free treatment option. Patients and Methods: MBC patients previously treated with chemotherapy were enrolled in a multicenter phase II study. Treatment consisted of gemcitabine (1,000 mg/m(2) i.v. on days 1 and 8) and carboplatin (AUC 4 i.v. on day 1) applied every 3 weeks. Results: Thirty-nine patients were recruited, and a total of 207 treatment cycles were applied with a median of 5 cycles per patient. One complete response and 11 partial responses were observed for an overall response rate of 31% (95% CI: 17-48%). Twelve patients (31%) had stable disease. Median time to progression was 5.3 months (95% CI: 2.6-6.7 months) and median overall survival from start of treatment was 13.2 months (95% CI: 8.7-16.7 months). Grade 3/4 hematological toxicity included leukopenia (59%/5%), thrombo-cytopenia (26%/23%) and anemia (10%/0%). Nonhematological toxicity was rarely severe. Conclusion: Combination chemotherapy with gemcitabine and carboplatin is an effective and generally well-tolerated treatment option for intensively pretreated patients with MBC. Due to a considerable incidence of severe thrombocytopenia it would be reasonable to consider starting gemcitabine at the lower dose level of 800 mg/m(2). Copyright (c) 2008 S. Karger AG, Basel

Dosimetric verification of the anisotropic analytical algorithm for radiotherapy treatment planning

BACKGROUND AND PURPOSE: To investigate the accuracy of photon dose calculations performed by the Anisotropic Analytical Algorithm, in homogeneous and inhomogeneous media and in simulated treatment plans. MATERIALS AND METHODS: Predicted dose distributions were compared with ionisation chamber and film measurements for a series of increasingly complex situations. Initially, simple and complex fields in a homogeneous medium were studied. The effect of inhomogeneities was investigated using a range of phantoms constructed of water, bone and lung substitute materials. Simulated treatment plans were then produced using a semi-anthropomorphic phantom and the delivered doses compared to the doses predicted by the Anisotropic Analytical Algorithm. RESULTS: In a homogeneous medium, agreement was found to be within 2% dose or 2mm dta in most instances. In the presence of heterogeneities, agreement was generally to within 2.5%. The simulated treatment plan measurements agreed to within 2.5% or 2mm. Conclusions: The accuracy of the algorithm was found to be satisfactory at 6MV and 10MV both in homogeneous and inhomogeneous situations and in the simulated treatment plans. The algorithm was more accurate than the Pencil Beam Convolution model, particularly in the presence of low density heterogeneities

Additive Manufacturing a Liquid Hydrogen Rocket Engine

Space Propulsion is a 5 day event being held from 2nd May to the 6th May 2016 at the Rome Marriott Park Hotel in Rome, Italy. This event showcases products like Propulsion sub-systems and components, Production and manufacturing issues, Liquid, Solid, Hybrid and Air-breathing Propulsion Systems for Launcher and Upper Stages, Overview of current programmes, AIV issues and tools, Flight testing and experience, Technology building blocks for Future Space Transportation Propulsion Systems : Launchers, Exploration platforms & Space Tourism, Green Propulsion for Space Transportation, New propellants, Rocket propulsion & global environment, Cost related aspects of Space Transportation propulsion, Modelling, Pressure-Thrust oscillations issues, Impact of new requirements and regulations on design etc. in the Automotive, Manufacturing, Fabrication, Repair & Maintenance industries

A study of the expressed feelings of prepared and unprepared expectant fathers

Thesis (M.S.)--Boston Universit

Recasting Cohn\u27s many sorted logic into a constrained logic

The use of a many sorted logic for theorem proving carries many advantages over a traditional unsorted logic. By placing restrictions on the search space, a many sorted logic can significantly reduce the amount steps in the resolution process. However, as a logic becomes more efficient, it increases in complexity. One of these efficient log ics is Cohn\u27s Many Sorted Logic, LLAMA. It uses complex data structures such as the sort lattice and sort arrays to maintain information about the sorts. Recasting LLAMA into Bürckert\u27s constrained logic will keep the functionality of LLAMA while using a format that reduces the complexity and maintains a more traditional resolution rule