نتایج جستجو برای: photon dose measurement

تعداد نتایج: 796871  

ژورنال: سنجش و ایمنی پرتو 2014

During the radiation therapy with electron beam, due to electron interaction and scattering from structures of the head of the medical linear accelerator, unwanted photons are produced. The main contribution of the photon contamination is resulted from the various components of the medical linear accelerator on the way of the high energy electron beam, and few percent is due to the interaction ...

2013
Qing Ai Dazhi Xu Su Yi A. G. Kofman C. P. Sun Franco Nori

We study the measurement-induced enhancement of the spontaneous decay for a two-level subsystem, wheremeasurements are treated as couplings between the excited state and an auxiliary state rather than the vonNeumann’s wave function reduction. The photon radiated in a fast decay of the atom, from the auxiliary state to the excited state, triggers a quasi-measurement, as opposed to a projectionme...

Journal: :Medical dosimetry : official journal of the American Association of Medical Dosimetrists 2015
Ahmed Salem Issa Mohamad Abdulmajeed Dayyat Haitham Kanaa'n Nasim Sarhan Ibrahim Roujob Abdel-Fattah Salem Shatha Afifi Imad Jaradat Rasmi Mubiden Abdelateif Almousa

Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-ele...

2000
E. Gargioni L. Büermann H. - M. Kramer

The physical basis for the measurement of Hp(10) and H*(10) in mixed high-energy electron and photon fields was developed for the general case of non-existing secondary charged particle equilibrium at the reference depth of 10 mm. Several mixed fields, with different electron fluence distributions were produced and the corresponding depth ionisation curves were measured in a Makrolon phantom. B...

2009
Silvia Vargas Castrillón Francisco Cutanda Henríquez

Several codes of practice for photon dosimetry are currently used around the world, supported by different organizations. A comparison of IPSM 1990 with both IAEA TRS-398 and AAPM TG-51 has been performed. All three protocols are based on the calibration of ionization chambers in terms of standards of absorbed dose to water, as it is the case with other modern codes of practice. This comparison...

Journal: :Physical review letters 2006
Kaoru Sanaka Kevin J Resch Anton Zeilinger

Unprecedented optical nonlinearities can be generated probabilistically in simple linear-optical networks conditioned on specific measurement outcomes. We describe a highly controllable quantum filter for photon number states, which takes advantage of such a measurement-induced amplitude nonlinearity. The basis for this filter is multiphoton nonclassical interference which we demonstrate for on...

Background: Prediction of the absorbed dose in irradiated volume plays an important role in the outcome of radiotherapy. Application of small fields for radiotherapy of thorax makes the dose calculation process inaccurate due to the existence of electronic disequilibrium and intrinsic deficiencies in dose calculation algorithms. To study the lung absorbed dose in radiotherapy with smal...

Ali Asghar Mowlavi, Mehdi Ghorbani Mona Azizi Zeinab Mohammadpoory

Introduction: One of scientific concern is increasing of unwanted neutron dose to the patient, in head and neck radiation therapy due to the presence of some isotopes in dental restorations and head of medical linac. The aim of this study is to measure the equivalent dose of thermal and fast neutron due to head of Siemens Primus Linac and a healthy tooth, Amalgam, Ni-Cr alloy a...

2010
Serge Rosenblum Alex Hayat Pavel Ginzburg David Neiman Meir Orenstein

We propose a scheme for quantum nondemolition measurement of photon holes based on electromagnetically induced transparency, which allows direct nondestructive detection of the photon holes. We analyze a scheme based on interaction of a photon hole signal and a coherent probe field with a three-level atomic medium. Using recent advances in electromagnetically induced transparency technology, we...

Journal: :Radiation protection dosimetry 2014
N J Roberts N A Horwood C J McKay

Standard neutron fields are invariably accompanied by a photon component due to the neutron-generating reactions and secondary neutron interactions in the surrounding environment. A set of energy-compensated Geiger-Müller (GM) tubes and electronic personal dosemeters (EPDs) have been used to measure the photon dose rates in a number of standard radionuclide and accelerator-based neutron fields....

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