Evaluation of a plane-parallel ionization chamber for low-energy radiotherapy beams
نویسندگان
چکیده
منابع مشابه
Perturbation correction factors for the NACP-02 plane-parallel ionization chamber in water in high-energy electron beams.
Recent dosimetry protocols for clinical high-energy electron beams recommend measurements of absorbed dose-to-water with a plane-parallel or cylindrical ionization chamber. For well-guarded plane-parallel ionization chambers, the ionization chamber perturbation factor in water, p(Q), has a recommended value of unity in all protocols. This assumption was investigated in detail in this study for ...
متن کاملEvaluation of dosimetry a performance parameter for a homemade farmer-type ionization chamber according to IEC60731
Introduction: Due to its simplicity, fast response and high reliability, ion chamber detectors are one of the most suitable dosimetry instruments for X and gamma rays. The dosimeter of photon beams, which used in radiotherapy centers, requires high accuracy and should pass requirements of IEC 60731 standards. About 80 percent of the IEC 60731 standard tests such as stabil...
متن کاملPositioning of a plane-parallel ionization chamber in clinical electron beams and the impact on perturbation factors.
Current dosimetry protocols recommend the use of plane-parallel ionization chambers for the dosimetry of clinical electron beams. The necessary perturbation corrections p(wall) and p(cav) are assumed to be unity, independent of the depth of measurement and the energy of the primary electrons. To verify these assumptions detailed Monte Carlo studies of a Roos chamber in clinical electron beams w...
متن کاملThe calibration and use of plane-parallel ionization chambers for dosimetry of electron beams.
The AAPM TG 39 protocol has proposed three different methods of calibrating plane-parallel ionization chambers, i.e., in-phantom irradiation with a high-energy electron beam and in-phantom and in-air 60Co irradiation. To verify the consistency of the three methods, we have measured Ngaspp values using each of these techniques for the five most commonly used plane-parallel chambers considered by...
متن کاملIonization chamber-based reference dosimetry of intensity modulated radiation beams.
The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the ab...
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ژورنال
عنوان ژورنال: Brazilian Journal of Radiation Sciences
سال: 2015
ISSN: 2319-0612,2319-0612
DOI: 10.15392/bjrs.v3i1a.62