Search results for "brachytherapy"
showing 8 items of 168 documents
Towards clinical application of RayStretch for heterogeneity corrections in LDR permanent 125-I prostate brachytherapy
2017
Purpose RayStretch is a simple algorithm proposed for heterogeneity corrections in low-dose–rate brachytherapy. It is built on top of TG-43 consensus data, and it has been validated with Monte Carlo (MC) simulations. In this study, we take a real clinical prostate implant with 71 125I seeds as reference and we apply RayStretch to analyze its performance in worst-case scenarios. Methods and Materials To do so, we design two cases where large calcifications are located in the prostate lobules. RayStretch resilience under various calcification density values is also explored. Comparisons against MC calculations are performed. Results Dose–volume histogram–related parameters like prostate D90, …
The use of nomograms in LDR-HDR prostate brachytherapy
2011
Purpose: The common use of nomograms in Low Dose Rate (LDR) permanent prostate brachytherapy (BT) allows to estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for each clinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adapt ed to High Dose Rate (HDR). This work sets nomograms for LDR and HDR prostate-BT implants, which are applied to three different institutions that use different implant techniques. Material and methods: Patients treated throughout 2010 till April 2011 were considered for this study. This exam ple was chosen to be the representative of the latest implant tech…
Source strength determination in iridium-192 and cobalt-60 brachytherapy : A European survey on the level of agreement between clinical measurements …
2021
Background and purpose: Brachytherapy treatment outcomes depend on the accuracy of the delivered dose distribution, which is proportional to the reference air-kerma rate (RAKR). Current societal recommendations require the medical physicist to compare the measured RAKR values to the manufacturer source calibration certificate. The purpose of this work was to report agreement observed in current clinical practice in the European Union. Materials and methods: A European survey was performed for high- and pulsed-dose-rate (HDR and PDR) highenergy sources (Ir-192 and Co-60), to quantify observed RAKR differences. Medical physicists at eighteen hospitals from eight European countries were contac…
Transitional cell carcinoma of endometrium: a case report of rare pure form
2018
Transitional cell carcinoma is a very rare histological subtype of endometrial cancer, with only 18 cases described in literature. Ovary represents the most common site where it accounts for 2% of all ovarian cancers. Due to the rarity of this disease, current management is controversial and includes various approaches, mostly described in the adjuvant setting, both radiotherapy and chemotherapy alone or in combination. Here, we report a case of a 65-year-old patient who underwent adjuvant vaginal brachytherapy for an endometrial transitional cell carcinoma. The patient was treated with radical total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH-BSO), without lymph-node sa…
Commissioning and quality assurance procedures for the HDR Valencia skin applicators
2016
The Valencia applicators (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden) are cup-shaped tungsten applicators with a flattening filter used to collimate the radiation produced by a high-dose-rate (HDR) 192 Ir source, and provide a homogeneous absorbed dose at a given depth. This beam quality provides a good option for the treatment of skin lesions at shallow depth (3-4 mm). The user must perform commissioning and periodic testing of these applicators to guarantee the proper and safe delivery of the intended absorbed dose, as recommended in the standards in radiation oncology. In this study, based on AAPM and GEC-ESTRO guidelines for brachytherapy units and our experience, a set …
Radiation protection of patients undergoing high-dose-rate brachytherapy: peripheral dose estimation, review of radiation risks and implant shielding…
2015
La braquiterapia (BT) es una modalidad de tratamiento de radioterapia en la que se coloca una fuente radiactiva encapsulada cerca, en contacto o en el interior del volumen a tratar. La desintegración de esta fuente produce la emisión de energía, lo que puede dar lugar a la muerte celular. Una dosis absorbida muy elevada (la dosis absorbida se define como la energía absorbida por unidad de masa) se deposita en un corto período de tiempo y en un pequeño número de fracciones. Para poder realizar un tratamiento de BT se requiere que el volumen de tratamiento sea accesible y bien delimitado en tamaño y forma. La BT se utiliza comúnmente como una modalidad de tratamiento eficaz para el cáncer de …
A study of Type B uncertainties associated with the photoelectric effect in low-energy Monte Carlo simulations
2021
The goal of this manuscript is to estimate Type B uncertainties in absorbed-dose calculations arising from the different implementations in current state-of-the-art Monte Carlo codes of low-energy photon cross-sections (<200 keV). Monte Carlo simulations are carried out using three codes widely used in the low-energy domain: PENELOPE-2018, EGSnrc, and MCNP. Mass energy-absorption coefficients for water, air, graphite, and their respective ratios; absorbed dose; and photon-fluence spectra are considered. Benchmark simulations using similar cross-sections have been performed. The differences observed between these quantities when different cross-sections are considered are taken to be a go…
I-125 seed calibration using the SeedSelectron(®) afterloader: a practical solution to fulfill AAPM-ESTRO recommendations.
2012
Purpose SeedSelectron® v1.26b (Nucletron BV, The Netherlands) is an afterloader system used in prostate interstitial permanent brachytherapy with I-125 selectSeed seeds. It contains a diode array to assay all implanted seeds. Only one or two seeds can be extracted during the surgical procedure and assayed using a well chamber to check the manufacturer air-kerma strength (SK) and to calibrate the diode array. Therefore, it is not feasible to assay 5–10% seeds as required by the AAPM-ESTRO. In this study, we present a practical solution of the SeedSelectron® users to fulfill the AAPM- ESTRO recommendations. Material and methods The method is based on: a) the SourceCheck® well ionization chamb…