The ionization chambers are widely utilized in diagnostic radiology quality control and dosimetry. They are simple to use, and can be found commercially in various types depending on their applications. They are the recommended devices for the determination of the beam qualities in mammographic range. To assure the reliability of the measurements, the stability of the response of the ionization...

A method for calibrating iodine-125 seeds in terms of exposure has been established. The standard free-air ionization chamber, used for measuring soft x rays, was chosen for the measurements. Arrays of four to six seeds were used to enhance the ionization-current-to-background-current ratio. Seeds from an array were measured individually in a re-entrant chamber. The quotient of the exposure rat...

The recalculation of 1 fraction from a patient treatment plan on a phantom and subsequent measurements have become the norms for measurement-based verification, which combines the quality assurance recommendations that deal with the treatment planning system and the beam delivery system. This type of evaluation has prompted attention to measurement equipment and techniques. Ionization chambers ...

Background: The aim of this work was to study the output factors for Linac using different ionization chambers and build up caps. Materials and Methods: Output factors were measured for open square fields (3 × 3 cm to 40 × 40 cm) defined by collimator jaws for 6 and 15 MV photon beams from a Varian Clinac 2100C accelerator were measured. The measurements in air were performed using Com...

introduction hadron-therapy is an effective technique used to treat tumors that are located between or nearby vital organs. the italian national center of oncological hadron-therapy (cnao) has been realized as the first facility in italy to treat very difficult tumors with protons and carbon ions. the on-line monitor system for cnao has been developed by the department of physics of the univers...

Acquisition of quasi-monoenergetic ("pristine") depth-dose curves is an essential task in the frame of commissioning and quality assurance of a proton therapy treatment head. For pencil beam scanning delivery modes this is often accomplished by measuring the integral ionization in a plane perpendicular to the axis of an unscanned beam. We focus on the evaluation of three integral detectors: two...

Recently, Quick-Scanning Extended X-ray Absorption Fine Structure Spectroscopy (QEXAFS) has become an important tool for in-situ characterization of materials and measurement of associated electronic structure for where samples have a short life due to X-ray damage. In this case, the time response of the ionization chamber affects the measurement resolution and therefore overall performance of ...