introduction for dose measurement in megavoltage (mv) photon beams with ion chambers, the effect of volume occupied by the air cavity is not negligible. therefore, the result of measurement should be corrected with a displacement perturbation correction factor (pdis) or using an effective point of measurement (epom). the aim of this study is to calculate the epom for cylindrical ion chamber and...

PURPOSE The purpose of this work is to assess the variation in performance of various commercially available dosimetry diodes for quantitative small field dosimetry, specifically by intercomparing measurements of SRS cone factors. METHODS Measurements were made in 6 MV photon beams with fixed SRS cones for two accelerator-based SRS systems: a Varian Clinac iX (Varian/Zmed cones) at 600 MU/min...

Computed tomography (CT) dosimetry normally uses an ionization chamber 100 mm long to estimate the computed tomography dose index (CTDI), however some reports have already indicated that small devices could replace the long ion chamber to improve quality assurance procedures in CT dosimetry. This paper presents a novel dosimetry system based in a commercial phototransistor evaluated for CT dosi...

Synthetic diamond is potentially one of the more interesting materials in the field of detectors applicable in dosimetry. It is, in fact, tissue equivalent (its atomic number, Z = 6, is very close to the actual atomic number of a biological tissue, Z = 7.5. Moreover it is not toxic and shows a high resistance to radiation damage, a high sensitivity and stability of response, a low leakage curre...

Out-of-field dose depends on multiple factors, making peripheral dosimetry com-plex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements...

Background: Attenuation coefficient (μ) plays an important role in calculations of treatment planning systems, as well as determination of dose distributions in external beam therapy, dosimetry, protection, phantom materials and industry. So, its exact measurement or calculation is very important. The aim of this study was to evaluate the μ in different points in the water phantom anal...