Search results for "RADIOTHERAPY"
showing 10 items of 473 documents
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…
Determination of consensus kQ values for megavoltage photon beams for the update of IAEA TRS-398
2020
The IAEA is currently coordinating a multi-year project to update the TRS-398 Code of Practice for the dosimetry of external beam radiotherapy based on standards of absorbed dose to water. One major aspect of the project is the determination of new beam quality correction factors, kQ, for megavoltage photon beams consistent with developments in radiotherapy dosimetry and technology since the publication of TRS-398 in 2000. Specifically, all values must be based on, or consistent with, the key data of ICRU Report 90. Data sets obtained from Monte Carlo (MC) calculations by advanced users and measurements at primary standards laboratories have been compiled for 23 cylindrical ionization chamb…
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…
Available evidence on re-irradiation with stereotactic ablative radiotherapy following high-dose previous thoracic radiotherapy for lung malignancies
2015
Patients affected with intra-thoracic recurrences of primary or secondary lung malignancies after a first course of definitive radiotherapy have limited therapeutic options, and they are often treated with a palliative intent. Re-irradiation with stereotactic ablative radiotherapy (SABR) represents an appealing approach, due to the optimized dose distribution that allows for high-dose delivery with better sparing of organs at risk. This strategy has the goal of long-term control and even cure. Aim of this review is to report and discuss published data on re-irradiation with SABR in terms of efficacy and toxicity. Results indicate that thoracic re-irradiation may offer satisfactory disease c…
The response behaviour of LiF:Mg,Cu,P thermoluminescence dosimeters to high-energy electron beams used in radiotherapy
1995
To ensure the effectiveness of radiation-therapy treatments, both in-phantom and in-patient reliable dose measurements are required. Thermoluminescence dosimeters are used commonly for both applications. Among the various available materials, the relatively new LiF:Mg,Cu,P phosphor is a suitable candidate for quality control of in vivo dosimetry in electron-beam therapy. The response behaviour of LiF:Mg,Cu,P chips to 6-21 MeV electron beams used in radiotherapy was studied. Batch homogeneity, dose linearity, sensitivity change after use, dose and dose-rate response, energy dependence and fading characteristics were investigated. The contribution from each factor to the overall uncertainty i…
Estudio transversal de medición de la composición corporal en pacientes con cáncer mediante antropometría y técnicas de imagen médica
2019
Introducción: Analizar la composición corporal tanto mediante técnicas antropométricas y parámetros bioquímicos clásicos, como mediante técnicas modernas utilizando tomografía computarizada (TC), en pacientes oncológicos antes de iniciar el tratamiento con radioterapia.Metodología: Se analizaron de forma retrospectiva 22 pacientes con diversos tumores del aparato digestivo, que fueron sometidos al TC de planificación antes de iniciar el tratamiento con radioterapia, y que disponían de un corte axial en la tercera vértebra lumbar. Para analizar la composición corporal, se determinaron tanto parámetros antropométricos y bioquímicos clásicos, como la determinación de la masa muscular mediante …
Generator-Based Radiopharmaceuticals for PET Dosimetry Before, During, and After Endoradiotherapy
2014
Generator-derived radionuclides for PET/CT imaging are promising for optimizing targeted radiotherapy by an individual patient-based approach, applying pre-therapeutic evaluation, dosimetric calculations, and for measuring treatment response after radionuclide therapy. To realize this vision, sophisticated nuclear chemistry and radiopharmaceutical chemistry should coincide with quantitative molecular imaging and dosimetric calculations.
Generator-based PET radiopharmaceuticals for molecular imaging of tumours: on the way to THERANOSTICS.
2011
Generator-derived radionuclides for PET/CT imaging are promising for optimizing targeted radiotherapy by an individual patient-based approach, applying pre-therapeutic evaluation, as well as dosimetric calculations, and for measuring treatment response after radionuclide therapy.
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 …