Purpose: To compare and evaluate the dosimetric water equivalence of several commonly used solid phantoms for low energy photon beams. Methods: A total ten different phantom materials was in study. The PENELOPE Monte Carlo code to calculate depth doses beam profiles all as well dose a small voxel at surface phantom. These were compared corresponding calculated primary beams ranged from 50 280 kVp. Results: number had excellent agreement x‐ray energies studied. RMI457 Solid Water, Virtual...

Purpose: PRESAGE ® is a dosimeter made of polyurethane, which suitable for 3D dosimetry in modern radiation treatment techniques. Since an ideal radiologically water equivalent, the authors investigated equivalency and radiological properties three different formulations that differ primarily their elemental compositions. Two are new have lower halogen content than original formulation. Methods: The equivalence was assessed by comparing densities, interaction probabilities, to corresponding...

Solid phantoms are widely used in radiation therapy for both relative and reference dosimetry. Two water equivalent phantoms, RMI-457 Water Plastic Water, were evaluated use kilovoltage x-ray dosimetry the energy range from 75 to 300 kVp. Relative measurements performed solid compared with water. The results indicate that could be output factor determination all energies tested measurement of percentage depth doses kVp beam, data agreeing within 1%, same For criteria, only beam. superior...

In this work, the authors have evaluated ten different ionization chambers for relative dosimetry of kilovoltage x-ray beams in energy range 50-280 kVp. Percentage depth doses water and detector response (in Solid Water air) were measured each studied using a number chambers. Measured dose data compared with Monte Carlo calculated EGSnrc package BEAMnrc user code. The accuracy phase space files generated by was verified calculating half-value layer comparing beam. results indicate that...

Purpose: Small field x‐ray beam dosimetry is difficult due to lack of lateral electronic equilibrium, source occlusion, high dose gradients, and detector volume averaging. Currently, there no single definitive recommended for small dosimetry. The objective this work was evaluate the performance a new commercial synthetic diamond detector, namely, PTW 60019 microDiamond, fields as used in stereotactic radiosurgery (SRS). Methods: sizes were defined by BrainLAB circular cones (4–30 mm...

The present study quantified surface doses on several rectangular phantom setups and curved phantoms for a 6 MV photon field using the Attix parallel‐plate chamber Gafchromic EBT2 film. For setups, homogenous water equivalent with 60 mm thick lung material were measured. measurement setup showed consistency in near‐surface between an open enhanced dynamic wedge (EDW) fields, whereas physical wedged fields small differences. Surface dose measurements made film good agreement results of...

Purpose: An experimental extrapolation technique is presented, which can be used to determine the relative output factors for very small x-ray fields using Gafchromic EBT3 film. Methods: Relative were measured Brainlab SRS cones ranging in diameters from 4 30 mm2 on a Novalis Trilogy linear accelerator with 6 MV x-rays. The factor was determined an reducing circular region of interest (ROI) developed remove effects volume averaging. This achieved by scanning film measurements high resolution...

The genipin radiochromic gel offers enormous potential as a three-dimensional dosimeter in advanced radiotherapy techniques. We have used several methods (including Monte Carlo simulation), to investigate the water equivalency of by characterizing its radiological properties, including mass and electron densities, photon interaction cross sections, energy absorption coefficient, effective atomic number, collisional, radiative total stopping powers scattering power. Depth doses were also...

A treatment planning system to compute intensity modulated radiotherapy (IMRT) treatments using inverse was investigated. The designed optimize the patterns required treat a specified target volume with normal structure constraints. beam model that uses convolution of pencil beams used dose distributions. multileaf collimator leaf‐setting sequence intended produce pattern computed along monitor units deliver each number fixed‐gantry fields. Computer calculations are commonly verified an...

Backscatter factors are important parameters in the determination of dose for kilovoltage x-ray beams. However, backscatter difficult to measure experimentally, and tabulated values based largely on Monte Carlo calculations. In this study we have determined new by both experimental methods, compared them with existing published AAPM TG-61 protocol. The purpose is twofold: (1) evaluate overall effectiveness using Gafchromic EBT film factor measurements (2) determine whether Carlo-calculated...

The Monte Carlo (MC) method has proven invaluable for radiation transport simulations to accurately determine doses and is widely considered a reliable computational measure that can substitute physical experiment where direct measurements are not possible or feasible. In the EGSnrc/BEAMnrc MC codes, there several user-specified parameters customized algorithms, which may affect calculation results. order fully utilize methods available in these it essential understand all options use them...

PRESAGE is a dosimeter that suitable for 3D dosimetry. To be used as an ideal dosimeter, however, it should present radiologically water equivalent properties. In this work, we have investigated the radiological properties of three different PRESAGE® formulations. The equivalence was assessed by comparing photon cross sections and radiation dosimetry formulations with corresponding values water. Relative depth doses were calculated using Monte Carlo methods 75, 125, 180 280 kVp 6 MV x-ray...

A new deformable polydimethylsiloxane (PDMS) based dosimeter is proposed that can be cast in an anthropomorphic shape and used for 3D radiation dosimetry of targets. The material has additional favorable characteristics as it tissue equivalent high-energy photons, easy to make non-toxic. In combination with dual wavelength optical scanning, a powerful dose verification image gated or organ tracked radiotherapy moving deforming

Kilovoltage x-ray beams are used to treat cancer on or close the skin surface. Many clinical cases use high atomic number materials as shielding reduce dose underlying healthy tissues. In this work, we have investigated effect both surface and depth doses in a water phantom with lead at phantom. The EGSnrc Monte Carlo code was simulate calculate using primary beam spectra derived from an analytical model. were energy range of 75-135 kVp field sizes 2, 5 8 cm diameter. sheet located beneath...