نتایج جستجو برای: gels radiometry dose
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Background: In this study the basic radiation properties of N-isopropylacrylamaide polymer gel dosimeter were determined together with verification of its soft tissue equivalency. Materials and Methods: The NIPAM gel was prepared and irradiated approximately 2 h after manufacturing. The magnetic resonance (MR) images were made 24 h after irradiation. The nuclear magnetic resonance (NMR) respons...
introduction: polymer gels are modern dosimeters providing three dimensional dose distributions. these dosimeters can be used in brachytherapy in which the tumor dimension is relatively small and the dose gradient is high. in this study, the ability of the magica polymer gel was investigated for assessing the absolute dose values as well as the dose distribution of low dose rate (ldr) ir-192 wi...
Dosimetry for targeted radionuclide therapy is a relatively young field. Although initial work can be traced back to the late 1940s (1), the MIRD Committee formalism that forms the foundation for most current approaches was published in the mid 1970s (2), and the drive for improved dosimetry to meet the requirements of targeted radionuclide therapy did not begin until the 1980s. During this per...
Artificial Neural Networks technology has been applied to unfold the neutron spectra and to calculate the effective dose, the ambient equivalent dose, and the personal dose equivalent for Cf and AmBe neutron sources. A Bonner sphere spectrometry with a LiI(Eu) scintillator was utilized to measure the count rates of the spheres that were utilized as input in two artificial neural networks, one f...
The reliability of radiation dose estimates in internal radionuclide therapy is directly related to the accuracy of activity estimates obtained at each imaging time point. The recently published MIRD pamphlet no. 23 provided a general overview of quantitative SPECT imaging for dosimetry. The present document is the first in a series of isotope-specific guidelines that will follow MIRD 23 and fo...
UNLABELLED Adult PET/CT acquisition protocols need to be modified for pediatric imaging to minimize the radiation dose while maintaining diagnostic utility. We developed pediatric PET/CT acquisition protocols customized to patient weight and estimated the dosimetry and cancer risk of these low-dose protocols to communicate basic imaging risks. METHODS Protocols were developed for whole-body (...
A brief overview is provided of the history of the development of internal dose methods for use in nuclear medicine. Basic methods of internal dosimetry and the systems that have been developed for use in nuclear medicine are described. The development of the MIRD system and the International Radiopharmaceutical Dosimetry Symposium series is outlined. The evolution of models and tools for calcu...
High dose rate brachytherapy (HDR) using 192Ir sources is well accepted as an important treatment option and thus requires an accurate dosimetry standard. However, a dosimetry standard for the direct measurement of the absolute dose to water for this particular source type is currently not available. An improved standard for the absorbed dose to water based on Fricke dosimetry of HDR 192Ir brac...
Recent investigations on mechanism of carcinogenesis have demonstrated important quantitative relationships between the induction of neoplasia, the molecular dose of promutagenic DNA adducts and their efficiency for causing base-pair mismatch, and the extent of cell proliferation in target organ. These factors are involved in the multistage process of carcinogenesis, including initiation, promo...
Investigations were conducted into chemical treatments suitable for concentrating enamel from cow teeth. Cow teeth could be used as alternative to human teeth for retrospective dosimetry when human teeth are not available. It is essential to remove dentin from tooth enamel for low dose radiation dosimetry in order to avoid interference to the ESR signal from organic radicals. Increasing the per...
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