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Vynckier S;International Atomic Energy Agency;International Commission on Radiation Units Measurements 《Radiation protection dosimetry》2004,110(1-4):565-572
Neutron therapy beams are obtained by accelerating protons or deuterons on Beryllium. These neutron therapy beams present comparable dosimetric characteristics as those for photon beams obtained with linear accelerators; for instance, the penetration of a p(65)+Be neutron beam is comparable with the penetration of an 8 MV photon beam. In order to be competitive with conventional photon beam therapy, the dosimetric characteristics of the neutron beam should therefore not deviate too much from the photon beam characteristics. This paper presents a brief summary of the neutron beams used in radiotherapy. The dosimetry of the clinical neutron beams is described. Finally, recent and future developments in the field of physics for neutron therapy is mentioned. In the last two decades, a considerable number of centres have established radiotherapy treatment facilities using proton beams with energies between 50 and 250 MeV. Clinical applications require a relatively uniform dose to be delivered to the volume to be treated, and for this purpose the proton beam has to be spread out, both laterally and in depth. The technique is called 'beam modulation' and creates a region of high dose uniformity referred to as the 'spread-out Bragg peak'. Meanwhile, reference dosimetry in these beams had to catch up with photon and electron beams for which a much longer tradition of dosimetry exists. Proton beam dosimetry can be performed using different types of dosemeters, such as calorimeters, Faraday cups, track detectors and ionisation chambers. National standard dosimetry laboratories will, however, not provide a standard for the dosimetry of proton beams. To achieve uniformity on an international level, the use of an ionisation chamber should be considered. This paper reviews and summarises the basic principles and recommendations for the absorbed dose determination in a proton beam, utilising ionisation chambers calibrated in terms of absorbed dose to water. These recommendations are based on the recent IAEA TRS398 Code of Practice: 'Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry based on Standards of Absorbed Dose to Water'. 相似文献
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Asselineau B Trompier F Texier C Itié C Médioni R Tikunov D Muller H Pelcot G;National Council on Radiation Protection Measurements 《Radiation protection dosimetry》2004,110(1-4):459-464
An international intercomparison of criticality accident dosimetry systems took place in the SILENE reactor, in June 2002. Participants from 60 laboratories irradiated their dosemeters (physical and biological) using two different configurations of the reactor. In preparation for this intercomparison, the leakage radiation fields were characterised by spectrometry and dosimetry measurements using the ROSPEC spectrometer associated with a NE-213 scintillator, ionisation chambers, GM counters, diodes and thermoluminescence dosemeters (TLDs). For this intercomparison, a large area was required to irradiate the dosemeters both in free air and on phantoms. Therefore, measurements of the uniformity of the field were performed with activation detectors and TLDs for neutron and gammas, respectively. This paper describes the procedures used and the results obtained. 相似文献
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上海光源及其在金属材料领域中的应用 总被引:1,自引:0,他引:1
扼要介绍了威力强大的第三代同步辐射装置——上海光源的主要特性、构造,第一期工程完成的七条X射线光束线站的主要性能指标、功能及适用领域,以及一些用通常实验室设备无法进行的在金属材料领域中的应用实例等。 相似文献
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