background: the natural radionuclides are always present in soil and care needs to be taken to minimize the radiation dose to humans. these radionuclides are mostly gamma ray emitting radionuclides which contribute to the radiation dose in long term behavior of radionuclides in soil. health hazards associated with natural radioactivity are of great concern and it is necessary to assess risk due...

National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 The NIST sealed water calorimeter is intended for direct measurement of absorbed dose to water. This calorimeter was used for a series of approximately 3700 measurements to investigate the so-called heat defect, that is, anomalous endothermic or exothermic effects caused by dissolved gases. The three systems investigate...

introduction: nasopharyngeal carcinoma is one of the most common malignancies in the head and neck region and radiotherapy is its treatment of choice. in spite of the fact that it is widely used, due to the presence of many sensitive organs or tissues in this region, patients may suffer from a wide range of side effects. one such sensitive tissue is the spinal cord. if the absorbed dose to spin...

For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ioniz...

background: natural radioactivity in materials under certain conditions can reach the hazardous radiological levels. so, it becomes necessary to study the natural radioactivity in different materials to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. materials and methods: ...

introduction: skin dose and depth dose distribution of some beta sources that can contaminate skin or protective clothing covering the skin have been calculated using varskin2. materials and methods: in this research, absorbed dose to skin and depth dose from the skin surface have been calculated for 90sr/90y, 147pm, 32p beta emitter radioisotopes by using input parameters: activity of source, ...

introduction evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. materials and methods a system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

to improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. the aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with 99m tc-marked diphosphonates ( 99m tc-mdp) by two different methods of background correction in conjugate view method. this study involved 22 pa...