نتایج جستجو برای: dosimetry verification
تعداد نتایج: 83031 فیلتر نتایج به سال:
Currently, the use of blood irradiation for inactivating pathogenic microbes in infected blood products and preventing graft-versus-host disease (GVHD) in immune suppressed patients is greater than ever before. In these systems, dose distribution and uniformity are two important concepts that should be checked. In this study, dosimetry of the gamma chamber blood irradiator model Gammacell 3000 ...
Postal dose audits for radiotherapy centers in Latin America and the Caribbean: trends in 1969-2003.
Since 1969 the International Atomic Energy Agency and the World Health Organization (along with the Pan American Health Organization, working with countries in Latin America and the Caribbean) have operated postal dosimetry audits based on thermoluminescent dosimetry (TLD) for radiotherapy centers. The purpose of these audits is to provide an independent dosimetry check of radiation beams used ...
Both polymer gels and PRESAGE radiochromic solid dosimeter, in conjunction with optical CT scanning system, have been employed to measure 3-D dose distribution. The 3-D dose maps obtained from these systems can provide a useful tool for dose verification on complex treatments such as IMRT, radiosurgery, and RapidArc. These complex treatments present high dose gradient regions in the boundaries ...
Dose calculations for intensity modulated radiation therapy (IMRT) require an accurate description of the radiation field defined by the multileaf collimator. A previously developed Monte Carlo phase space model has been modified to provide accurate dose verification for IMRT treatments on a Novalis linear accelerator. We have incorporated into the model the effects of the multileaf collimator ...
A preliminary investigation into the efficacy of a new 3D dosimetry material, RadGel™, for verification of radiation therapy dose distributions is presented. Small volumes of RadGel™ were found to exhibit a linear, reproducible response to dose. A gradual increase in optical-density (OD) with time was observed, suggesting scanning should be completed within 18 hours to keep a linear correlation...
In order to provide automatic IMRT dose delivery with an add-on MMLC a technical integration of a MMLC system with a linear accelerator was realized. The principle of this integration and the changes and enhancements of the existing hard- and software are briefly described. The system was tested by the automatic delivery of an IMRT plan designed for a head and neck phantom. A verification of do...
Computed tomography (CT)/magnetic resonance imaging (MRI) fusion is considered to be the best method for postimplant dosimetry of permanent prostate brachytherapy; however, it is inconvenient and costly. In T2*-weighted image (T2*-WI), seeds can be easily detected without the use of an intravenous contrast material. We present a novel method for postimplant dosimetry using T2*-WI/T2-weighted im...
Light dosimetry is an important parameter that affects the efficacy of photodynamic therapy (PDT). However, the irregular morphologies of lesions complicate lesion segmentation and light irradiance adjustment. Therefore, this study developed an illumination demo system comprising a camera, a digital projector, and a computing unit to solve these problems. A three-dimensional model of a lesion w...
A survey of the literature was conducted to establish the anticipated ranges of exposure to both physicians and patients during cardiac catheterization. A brief explanation of a technic for using time-lapse photography and a computer model for exposure calculation is presented. The thermoluminescent dosimeter (TLD) results used as controls for exposure values calculated by the developed techniq...
John Gore’s seminal 1984 paper on gel dosimetry spawned a vibrant research field ranging from fundamental science through to clinical applications. A preliminary bibliometric study was undertaken of the gel dosimetry family of publications inspired by, and resulting from, Gore’s original 1984 paper to determine active growth areas, research trends and hot topics from Gore’s paper up to and incl...
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