[en] Radiation dose outside the radiotherapy treatment field can be significant and therefore is of clinical interest in estimating organ doses. In a previous paper we reported the results of measurements made using unmodified radiation fields. We have extended this study to include the effects of wedge filters and blocks. For a given dose on the central axis of a radiation field, wedges can cause a factor of 2 to 4 increase in dose at any point outside the field compared with the dose when no wedge is used. Adding blocks to a treatment field can cause an increase in dose at points outside the field, but the effect is much smaller than the effect of a wedge, and generally less than a factor of 2. From the results of these measurements, doses to selected organs outside the field for specified treatment geometries were estimated, and the potential for reducing these organ doses by additional shielding was assessed

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[en] This treatise reviews current methodology and theory of radiation measurement and dosimetry and is designed to supplement the three-volume Radiation Dosimetry, Second Edition. To incorporate advances in this changing field, recognized authorities approach the subject with new theoretical insights and applied techniques. The chapters in Volume II include coverage of new detector systems for radiation measurements in neutron and photon fields, as well as techniques for interpreting data; new designs for calorimeters and temperature measurement methods; and new methods for measuring high-intensity pulsed radiation. CONTENTS: Relationship of Microdosimetric Techniques to Applications in Biological Systems; Neutron Spectroscopy; Ionization Chambers; Advances in Calorimetry for Radiation Dosimetry; External Beta-Photon Dosimetry for Radiation Protection; Each chapter includes references. Index

[en] This book discusses the papers on dosimetry of ionizing radiation. The topics covered are: theoretical basis for dosimetry; fundamentals of microdosimetry; dosimetry of external radiation beams of photon and electron radiation; beam characteristics dosimetry of nuclear particles; measurement and dosimetry of radioactivity in the environment; and internal dosimetry for radiation protection

[en] This book presents summaries of the current information on subtopics in dosimetry of ionizing radiation; each accompanied by an extensive reference list

[en] The EGS4 electron-photon Monte Carlo code has been used to study the characteristics of the bremsstrahlung x-rays generated from the interaction of circulating electrons with the residual gas in accelerator storage rings. Gas bremsstrahlung dose rates are given for various opening angles as a function of the electron beam energy ranging from 0.5--10 GeV. Photon and neutron dose rates, generated from various devices struck by gas bremsstrahlung in a synchrotron radiation beamline, are also presented along with the photon spectral and transmission results. The EGS4-predicted results are found to be in basic agreement with the measurements made at the Stanford Synchrotron Radiation Laboratory. Figures, equations, and a simple method useful for the photon-neutron shielding design for beamlines are provided

[en] The production and transport of the photoneutrons from the giant-dipoleresonance reaction have been implemented in a coupled EGS4-MORSE code. The total neutron yield (including both the direct neutron and evaporation neutron components) is calculated by folding the photoneutron yield cross sections with the photon track length distribution in the target. Empirical algorithms based on the measurements have been developed to estimate the fraction and energy of the direct neutron component for each photon. The statistical theory in the EVAP4 code, incorporated as a MORSE subroutine, is used to determine the energies of the evaporation neutrons. These represent major improvements over other calculations that assumed no direct neutrons, a constant fraction of direct neutrons, monoenergetic direct neutron, or a constant nuclear temperature for the evaporation neutrons. It was also assumed that the slow neutrons (< 2.5 MeV) are emitted isotropically and the fast neutrons are emitted anisotropically in the form of 1+Csin²θ, which have a peak emission at 900. Comparisons between the calculated and the measured photoneutron results (spectra of the direct, evaporation and total neutrons; nuclear temperatures; direct neutron fractions) for materials of lead, tungsten, tantalum and copper have been made. The results show that the empirical algorithms, albeit simple, can produce reasonable results over the interested photon energy range

[en] Dose and integral dose from bremsstrahlung in a 10-MeV electron beam were measured for irradiation of large areas with 120⁰ -arc rotational fields. The maximum bremsstrahlung dose ranged from 2 to 7% of the maximum electron dose for the different beam arrangements, while the integral dose showed the same range of variation. The concomitant bremsstrahlung beam should be collimated by the x-ray photon collimators and the use of narrow field rotations avoided

No abstract available

No abstract available