نتایج جستجو برای: internal radiation
تعداد نتایج: 464914 فیلتر نتایج به سال:
All building materials contain various amounts of natural radioactive nuclides. Materials derived from rock and soil contain mainly natural radionuclides of the uranium (238U) and thorium (232Th) series, and the radioactive isotope of potassium (40K). Radiation exposure due to building materials can be divided into external and internal exposure. The external exposure is caused by direct gamma ...
Background: The fundamental principles of internal targeted alpha therapy for cancer were established many decades ago.The high linear energy transfer (LET) of alpha radiation to the targeted cancer cellscauses double strand breaks in DNA. At the same time, the short range radiation spares adjacent normal tissues. This targeted approach complements conventional external beam radiotherapy and ch...
Therapy for large symptomatic keloids is often plagued with complicated reconstruction manner and recurrence. This article reports a rare treatment combination for a chest keloid with internal mammary artery perforator flap reconstruction and radiation therapy. We excised the keloid and covered the defect with an internal mammary artery perforator flap. Immediate electron-beam irradiation thera...
In the standard internal shock model, the observed X and gamma–ray radiation is assumed to be produced by synchrotron emission. I will show that there are serious problems with this interpretation, calling for other radiation mechanisms, such as quasi–thermal Comptonization and/or Compton drag processes, or both. These new ideas can have important consequences on the more general internal shock...
Introduction: In this study, organ radiation doses were calculated for the renal agent 99mTc-DTPA in children. Bio-kinetic energy of 99mTc-DTPA was evaluated by scintigraphy and estimates for absorbed radiation dose were provided using standard medical internal radiation dosimetry (MIRD) techniques.Material and Methods: In this applied research, fourteen children patients (6 males and 8 females...
A gyrotron internal mode converter consists of a launcher that radiates the waveguide mode as a nearly Gaussian beam in free space, followed by a set of mirrors to focus and direct the radiation. We present a calculation of the radiation from the launcher based on a quasi-optical approach that includes diffraction. The results are in good agreement with a calculation using a numerical code base...
We examined the effects of chronic exposure to radionuclides, primarily uranium and mixed-fission products, on cancer mortality in a retrospective cohort study of workers enrolled in the radiation-monitoring program of a nuclear research and development facility. Between 1950 and 1994, 2,297 workers were monitored for internal radiation exposures, and 441 workers died, 134 (30.4%) of them from ...
Background: Reliable estimation of radiation-absorbed dose is necessary to evaluate the benefits and the risks of radiopharmaceuticals used for diagnostic or therapeutic purposes in nuclear medicine. Materiel and Methods: This study included 47 patients treated with iodine-131 for Graves’ disease. A comparative study between Geant4 Monte Carlo simulation and MIRD formalism was carried out to ev...
In this chapter, there is insufficient space to exhaustively review the research which has been carried out on internal radionuclide effects. I hope only to highlight evidence which shows that internal radionuclides cannot be assessed by the current radiation risk model, and to suggest some research directions that may enable a new model to be developed, one which more accurately quantifies the...
Mushrooms are recognized as one of the main contributors to internal radiation exposure from the activity concentration of radiocesium released by the accident at the Chernobyl nuclear power plant (CNNP). We evaluated the activity concentrations of the artificial radionuclides (radiocesium) in wild mushrooms collected in 2015 from Korosten and Lugine, Zhitomir region, Ukraine, located 120 km aw...
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