Search results for "High-Dose Rate Brachytherapy"
showing 10 items of 13 documents
Dosimetry comparison between TG-43 and Monte Carlo calculations using the Freiburg flap for skin high-dose-rate brachytherapy
2012
Abstract Purpose The purpose of this work was to evaluate whether the delivered dose to the skin surface and at the prescription depth when using a Freiburg flap applicator is in agreement with the one predicted by the treatment planning system (TPS) using the TG-43 dose-calculation formalism. Methods and Materials Monte Carlo (MC) simulations and radiochromic film measurements have been performed to obtain dose distributions with the source located at the center of one of the spheres and between two spheres. Primary and scatter dose contributions were evaluated to understand the role played by the scatter component. A standard treatment plan was generated using MC- and TG-43-based TPS appl…
Interobserver variability in rectum contouring in high-dose-rate brachytherapy for prostate cancer: A multi-institutional prospective analysis
2017
PURPOSE: The aim of this study was to evaluate the interobserver variability (KW) of rectum contouring, and its dosimetric consequences, for high-dose-rate brachytherapy in patients with prostate cancer across multiple institutions. METHODS AND MATERIALS: Five radiation oncologists contoured rectums in 10 patients on transperineal ultrasound image sets after establishing a delineation consensus. The D-0.1cc, D-1cc, and D-2cc rectum volume parameters were determined. The mean, standard deviation, and range of each dose-volume histogram parameter were evaluated for each patient. The JOY was determined using the coefficient of variation, and the dosimetric impacts on the total dose were analyz…
On the use of the absorbed depth-dose measurements in the beam calibration of a surface electronic high-dose-rate brachytherapy unit, a Monte Carlo-b…
2019
PURPOSE To evaluate the use of the absorbed depth-dose as a surrogate of the half-value layer in the calibration of a high-dose-rate electronic brachytherapy (eBT) equipment. The effect of the manufacturing tolerances and the absorbed depth-dose measurement uncertainties in the calibration process are also addressed. METHODS The eBT system Esteya® (Elekta Brachytherapy, Veenendaal, The Netherlands) has been chosen as a proof-of-concept to illustrate the feasibility of the proposed method, using its 10 mm diameter applicator. Two calibration protocols recommended by the AAPM (TG-61) and the IAEA (TRS-398) for low-energy photon beams were evaluated. The required Monte Carlo (MC) simulations w…
Limitations of the TG-43 formalism for skin high-dose-rate brachytherapy dose calculations
2014
Purpose: In skin high-dose-rate (HDR) brachytherapy, sources are located outside, in contact with, or implanted at some depth below the skin surface. Most treatment planning systems use the TG-43 formalism, which is based on single-source dose superposition within an infinite water medium without accounting for the true geometry in which conditions for scattered radiation are altered by the presence of air. The purpose of this study is to evaluate the dosimetric limitations of the TG-43 formalism in HDR skin brachytherapy and the potential clinical impact. Methods: Dose rate distributions of typical configurations used in skin brachytherapy were obtained: a 5 cm × 5 cm superficial mould; a …
Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions
2016
Purpose: The aims of this study were (i) to design a new high-dose-rate (HDR) brachytherapy applicator for treating surface lesions with planning target volumes larger than 3 cm in diameter and up to 5 cm in size, using the microSelectron-HDR or Flexitron afterloader (Elekta Brachytherapy) with a 192Ir source; (ii) to calculate by means of the Monte Carlo(MC) method the dose distribution for the new applicator when it is placed against a water phantom; and (iii) to validate experimentally the dose distributions in water. Methods: The penelope2008MC code was used to optimize dwell positions and dwell times. Next, the dose distribution in a water phantom and the leakage dose distribution arou…
WE-C-108-08: Organ Doses in a Male Phantom Undergoing High-Dose-Rate Brachytherapy Applied to the Prostate
2013
Purpose: The aim of this study was to obtain equivalent doses to radiosensitive organs when applying high‐dose‐rate (HDR) brachytherapy to the prostate using60 Co or 192 Ir sources, and in comparison to external‐beam radiotherapy (EBRT) modalities. Methods: Monte Carlo simulations in Geant4 were performed using a voxelized adult reference man described in Publication 110 by the International Commission on Radiological Protection (ICRP). Point sources of 60Co or 192Ir with photon energy spectra corresponding to those exiting their capsules were placed in the center of the prostate. Equivalent doses per therapeutic absorbed dose to the prostate were obtained in several radiosensitive organs. …
SU-FF-T-41: Monte Carlo Dosimetric Study of the New BEBIG Co-60 HDR Source
2005
Purpose: The use of high dose rate brachytherapy (HDR) is a highly extended practice today, being the Ir‐192 the most widely extended isotope used for this type of practice although Co‐60 is also available for HDR. The purpose of this study is to obtain the dosimetric parameters of the Co‐60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there is no dosimetric data available in the literature. It is recommended that accurate dose distribution data, based on a realistic geometry and on the mechanical characteristics of the source, should be obtained by an appropriate method, experimental or Monte Carlo, to be used as input in the HDR Treatment Plannin…
Dosimetric perturbations of a lead shield for surface and interstitial high-dose-rate brachytherapy.
2014
In surface and interstitial high-dose-rate brachytherapy with either (60)Co, (192)Ir, or (169)Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields…
Technical note: Dosimetric study of a new Co-60 source used in brachytherapy
2007
The purpose of this study is to obtain the dosimetric parameters of a new Co-60 source used in high dose rate brachytherapy and manufactured by BEBIG (Eckert & Ziegler BEBIG GmbH, Germany). The Monte Carlo method has been used to obtain the dose rate distribution in the updated TG-43U1 formalism of the American Association of Physicists in Medicine. In addition, to aid the quality control process on treatment planning systems (TPS), a two-dimensional rectangular dose rate table, coherent with the TG-43U1 dose calculation formalism, is given. These dosimetric data sets can be used as input data of the TPS calculations and to validate them.
Monte Carlo dosimetric study of the BEBIG Co-60 HDR source
2005
Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as w…