1,721,351 research outputs found
Radiotherapie der nichtkleinzelligen Lungenkarzinome (Radiotherapy of non-small-cell lung cancer
No full textHeavy Charged Particles: Does Improved Precision and Higher Biological Effectiveness Translate to Better Outcome in Patients?
No full textProtons are the most common charged particles used in oncology. Acceleration of heavier ions requires larger accelerators and is more expensive, yet heavy nuclei share the same advantageous dose-depth profile characteristics of protons and have potential additional advantages. These advantages are related to the physical characteristics of the beam, owing to reduced lateral scattering and sharper lateral penumbra. In addition, heavy ions produce an increased biological response. In fact, in the target region heavy ions behave as densely ionizing radiation, which produce distinct biological effects compared to sparsely ionizing x-rays and protons. The translation of the putative radiobiological advantages into clinical advantages remains to be demonstrated. Eleven centers worldwide are currently using carbon ions for treatment of different solid tumors. Phase-II trials in Japan and Germany show very promising results for selected tumors, such as chordomas, large sarcomas, and pancreatic adenocarcinoma. Phase-III trials are under way to compare carbon ions to protons or x-rays
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Adjuvant treatment of brain metastases
No full textWith an incidence of 15/10(5) in the general population, brain metastases constitute a serious, debilitating complication in cancer patients. The majority of those patients suffer from more than one metastasis, but up to 30% to 40% present with a solitary lesion. Whole-brain radiotherapy (WBRT) extends median survival from 1 to 2 months for treatment with steroids only, to 4 to 6 months in most series. However, long-term survival(>l-2 years) is observed in up to 10% of patients with favorable prognostic factors, such as solitary lesions, good Karnofsky performance status, and absence of extracranial disease. For those patients, individually optimized treatment is worthwhile. For good-prognosis patients with controlled extracranial disease, surgery in combination with postoperative WBRT should be considered, especially when fast relief of symptoms is mandated. For surgically inaccessible solitary lesions below a size threshold of approximately 30 ccm, stereotactic radiosurgery (RS), although never compared to surgery in a randomized fashion, seems to yield comparable results and is the treatment of choice for more than one lesion in appropriately selected patients. Nevertheless, a number of questions concerning the optimal treatment regimens for brain metastases remain. These mainly concern the radiation dose, need for a combination of RS and WBRT, relative timing of different treatment modalities, and maximum number of brain metastases that can reasonably be treated with RS when long-term progression-free survival is the peal. However, RS is definitely an excellent option for salvage and palliation in patients with short life expectancy, as it is simultaneously noninvasive and cost-effective, with short hospitalization times. (C) 2001 Wiley-Liss, Inc
Proton and carbon ion radiotherapy for primary brain tumors and meningeomas delivered with active rasterscanning at the Heidelberg Ion Therapy Center (HIT): Initial treatment results and study concepts
No full textAlkylans after alkylans: therapy results after the use of ACNU in progressive glioblastoma after primary combined radiochemotherapy as well as adjuvant chemotherapy with temozolomide
No full textStereotactic radiation therapy of liver metastases
No full textPurpose. A number of minimal-invasive methods have been developed for the treatment of non-resectable liver metastases. A focused high dose can be delivered to a liver tumor with sparing of surrounding normal liver tissue using non-invasive stereotactic techniques. Methods. Sixty-six metastases were treated stereotactically in 43 patients during a phase 2 trial. Results. There were no major side effects observed. The actuarial local control was 82% after 18 months. The median actuarial survival was 24 months. However, there was a significantly improved survival in patients without additional extrahepatic tumor manifestation at the time of treatment compared to those, who were treated in palliative intention (87% vs. 24% after 18 months, p=0.001 (log-rank). Conclusion. Stereotactic single dose irradiation is a non-invasive and safe treatment option for patients with inoperable liver metastases. Phase III studies will further evaluate this new approach
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