Search results for "Brachytherapy"
showing 10 items of 168 documents
A dosimetric study on the Ir-192 high dose rate Flexisource
2006
In this work, the dose rate distribution of a new Ir-192 high dose rate source (Flexisource used in the afterloading Flexitron system, Isodose Control, Veenendaal, The Netherlands) is studied by means of Monte Carlo techniques using the GEANT4 code. The dosimetric parameters of the Task Group No. 43 Report (TG43) formalism and two-dimensional rectangular look-up tables have been obtained.
Monte Carlo calculation of the TG-43 dosimetric parameters of a new BEBIG Ir-192 HDR source
2005
Background and purpose: High dose rate (HDR) brachytherapy is a highly extended practice in clinical brachytherapy today. Quality dose rate distribution datasets of the HDR sources used in a clinical treatment are required. Because of the different source designs, a specific dosimetry dataset is required for each source model. In the recently published BRAPHYQS-ESTRO Report, an overview of available dosimetric data for all HDR Ir-192 sources is given, pointing out the lack of data for one of the sources that is used by the BEBIG MultiSource afterloading system (BEBIG GmbH, Germany). The purpose of this study is to obtain detailed dose rate distributions in liquid water media around this sou…
Laparoscopic lymph node dissection should be performed before fertility preserving treatment of patients with cervical cancer
2012
Objective: The aim of this study is to assess our results of treatment of women with stage I cervical cancer > 2 cm in diameter seeking fertility preservation. Treatment consisted of Laparoscopic Pelvic and Paraaortic Lymphadenectomy (LPPLND), and when no nodal metastasis was detected, neoadjuvant chemotherapy (NACT) followed by radical vaginal trachelectomy (RVT). Patients with positive lymph nodes underwent primary chemoradiation. Methods: A cohort of women younger than 40 years of age with stage I disease > 2 cm who underwent LPPLND and either NACT and RVT or chemoradiation. Oncological outcome was evaluated prospectively. Results: Eighteen women were eligible for this study. Twelve (67%…
Perioperative morbidity and rate of upstaging after laparoscopic staging for patients with locally advanced cervical cancer: results of a prospective…
2015
Objective The International Federation of Gynecology and Obstetrics (FIGO) staging for cervical cancer is based on clinical examination. Previous studies have demonstrated significant upstaging with surgical staging. However, no randomized trial has ever shown a survival benefit when radiation combined with chemoradiation (RCTX) is modified according to surgical staging. The objective of the study was to evaluate the feasibility and outcomes of surgical staging prior to radical RCTX treatment among patients with locally advanced cervical cancer in the setting of a larger, prospective, randomized study (the Uterus-11 study of the German Gynecologic Oncology Group). Study Design Between 2009 …
Brachytherapy heterogeneity correction algorithm
2011
El objetivo de este trabajo de investigación es el estudio de la influencia de heterogeneidades de los tejidos en la dosimetría de braquiterapia. En concreto, hemos desarrollado un algoritmo que tiene en cuenta las calcificaciones localizadas dentro de la próstata y corrige la dosis de referencia en agua. Este algoritmo está basado en un modelo analítico y es aplicable a Sistemas de Planificación del Tratamiento (TPS) comerciales. El modelo analítico tiene un fundamento teórico consistente, y se basa en los valores de referencia (caso homogéneo) y en la definición de una longitud efectiva, que transforma el recorrido dentro de la calcificación en distancias mayores. La energía depositada en…
Calculated organ doses using Monte Carlo simulations in a reference male phantom undergoing HDR brachytherapy applied to localized prostate carcinoma
2013
Purpose : The aim of this study was to obtain equivalent doses in radiosensitive organs (aside from the bladder and rectum) when applying high-dose-rate (HDR) brachytherapy to a localized prostate carcinoma using60Co or 192 Ir sources. These data are compared with results in a water phantom and with expected values in an infinite water medium. A comparison with reported values from proton therapy and intensity-modulated radiation therapy (IMRT) is also provided. Methods : Monte Carlo simulations in Geant4 were performed using a voxelized phantom described in International Commission on Radiological Protection (ICRP) Publication 110, which reproduces masses and shapes from an adult reference…
Monte Carlo dosimetric study of the Flexisource Co-60 high dose rate source.
2011
Purpose: Recently, a new HDR 60 Co brachytherapy source, Flexisource Co-60, has been developed (Nucletron B.V. Veenendaal, The Netherlands). This study aims to obtain dosimetric data for this source for its use in clinical practice as required by AAPM and ESTRO. Material and methods: Two Monte Carlo radiation transport codes were used: Penelope2008 and GEANT4. The source was centrally-positioned in a 100 cm radius water phantom. Absorbed dose and collisional kerma were obtained using 0.01 cm (close) and 0.1 cm (far) sized voxels to provide high-resolution dosimetry near (far from) the source. Dose rate distributions obtained with the two Monte Carlo codes were compared. Results and Discussi…
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. …
Monte Carlo dosimetric study of Best Industries and Alpha Omega Ir-192 brachytherapy seeds
2004
Ir-192 seeds are widely used in the USA for low dose rate interstitial brachytherapy. There are two commercially available models: those manufactured by Best Industries filtered with stainless steel, and those manufactured by Alpha-Omega seeds filtered with Pt. Newly developed 3D correction algorithms for brachytherapy are based on dosimetry data obtained on unbounded phantom size, allowing corrections for heterogeneities and actual tissue boundaries. Published dosimetric datasets for both seeds have been obtained under bounded conditions. The aim of the present study is to obtain dosimetric datasets for these seeds under full scatter conditions. The Monte Carlo GEANT4 code has been used to…
Evaluation of interpolation methods for TG-43 dosimetric parameters based on comparison with Monte Carlo data for high-energy brachytherapy sources.
2010
Purpose The aim of this work was to determine dose distributions for high-energy brachytherapy sources at spatial locations not included in the radial dose function gL(r) and 2D anisotropy function F(r,θ) table entries for radial distance r and polar angle θ. The objectives of this study are as follows: 1) to evaluate interpolation methods in order to accurately derive gL(r) and F(r,θ) from the reported data; 2) to determine the minimum number of entries in gL(r) and F(r,θ) that allow reproduction of dose distributions with sufficient accuracy. Material and methods Four high-energy photon-emitting brachytherapy sources were studied: 60Co model Co0.A86, 137Cs model CSM-3, 192Ir model Ir2.A85…