نتایج جستجو برای: organs at risk
تعداد نتایج: 4357260 فیلتر نتایج به سال:
BACKGROUND In carbon ion radiotherapy (CIR) for esophageal cancer, organ and target motion is a major challenge for treatment planning due to potential range deviations. This study intends to analyze the impact of intrafractional variations on dosimetric parameters and to identify favourable settings for robust treatment plans. METHODS We contoured esophageal boost volumes in different organ ...
PURPOSE The current inverse planning methods for intensity modulated radiation therapy (IMRT) are limited because they are not designed to explore the trade-offs between the competing objectives of tumor and normal tissues. The goal was to develop an efficient multiobjective optimization algorithm that was flexible enough to handle any form of objective function and that resulted in a set of Pa...
A consensus conference including thirty experts was held in April, 2007, to discuss risk factors for breast cancer and their management. Four categories of risk were outlined, from breast cancer "average" through "very high" risk, the latter including individuals with high penetrance BRCA1/2 gene mutations. Guidelines for management of patients in each of these categories were discussed, with t...
Background: Three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) techniques are used for the treatment of patients with laryngeal cancer. Objective: This study aimed to investigate the effects of these 2 treatment techniques on the planning target volume (PTV) (laryngeal cancer), dose homogeneity, dose of organs at...
It is known that circumventricular organs that are located around the ventricular system of the brain are lack of blood-brain barrier and support the body water-salt balance. They also effect many physiological events such as some neuroendocrine and reproduction mechanisms. In different pathological conditions their results and the step in which the circumventricular organs are affected are unk...
We have examined the roles of three circumventricular organs, the area postrema, the subfornical organ, and the organum vasculosum of the lamina terminalis (OVLT), as possible access points for circulating pyrogens to cause fever. In conscious, unrestrained rats prepared with telemetry devices, intracerebroventricular cannulas, and intravenous catheters, body temperature was monitored after int...
BACKGROUND Tumor-Treating Fields (TTFields) are a novel treatment strategy for glioblastoma (GBM) that is approved for the use concomitantly to adjuvant chemotherapy. Preclinical data suggest a synergistic interaction of TTFields and radiotherapy (RT). However, the dosimetric uncertainties caused by the highly dense arrays have led to caution of applying the TTF setup during RT. METHODS In a ...
This paper presents a greedy heuristic-based double iteration and rectification (DIR) approach to intraoperative planning for permanent prostate brachytherapy. The DIR approach adopts a greedy seed selection (GSS) procedure to obtain a preliminary plan. In this process, the potential seeds are evaluated according to their ability to irradiate target while spare organs at risk (OARs), and their ...
BACKGROUND To moving lung tumors, we applied a respiratory-gated strategy to carbon-ion pencil beam scanning with multiple phase-controlled rescanning (PCR). In this simulation study, we quantitatively evaluated dose distributions based on 4-dimensional CT (4DCT) treatment planning. METHODS Volumetric 4DCTs were acquired for 14 patients with lung tumors. Gross tumor volume, clinical target vo...
Short-term patient and graft outcomes continue to improve after kidney and liver transplantation, with 1-year survival rates over 80%; however, improving longer-term outcomes remains a challenge. Improving the function of grafts and health of recipients would not only enhance quality and length of life, but would also reduce the need for retransplantation, and thus increase the number of organs...
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