Search results for "RADIATION"

Artefacts in CBCT: a review

2011

Artefacts are common in today's cone beam CT (CBCT). They are induced by discrepancies between the mathematical modelling and the actual physical imaging process. Since artefacts may interfere with the diagnostic process performed on CBCT data sets, every user should be aware of their presence. This article aims to discuss the most prominent artefacts identified in the scientific literature and review the existing knowledge on these artefacts. We also briefly review the basic three-dimensional (3D) reconstruction concept applied by today's CBCT scanners, as all artefacts are more or less directly related to it.

Clinical indications for cardiac computed tomography. From the Working Group of the Cardiac Radiology Section of the Italian Society of Medical Radio…

2012

"\"La tomografia computerizzata del cuore (CCT) è diventata uno strumento efficace in differenti contesti clinici. Lo sviluppo della tecnologia ha portato ad una progressiva espansione delle indicazioni con una concomitante riduzione della dose di radiazioni necessaria per l’esecuzione dell’indagine. Ancora oggi sono pochi i documenti delle maggiori società scientifiche internazionali che si esprimono sulle effettive modalità di utilizzo e sulle indicazioni cliniche della CCT; in particolare mancano delle linee guida complete. Questo documento rispecchia la visione del gruppo di lavoro della Sezione di Cardio-Radiologia della Società Italiana di Radiologia Medica in merito alle indicazioni …

A practical MRI-based reconstruction method for a new endocavitary and interstitial gynaecological template

2015

Purpose: There are perineal templates for interstitial implants such as MUPIT and Syed applicators. Their limitations are the intracavitary component deficit and the necessity to use computed tomography (CT) for treatment planning since both applicators are non-magnetic resonance imaging (MRI) compatibles. To overcome these problems, a new template named Template Benidorm (TB) has been recently developed. Titanium needles are usually reconstructed based on their own artifacts, mainly in T1-weighted sequence, using the void on the tip as the needle tip position. Nevertheless, patient tissues surrounding the needles present heterogeneities that complicate the accurate identification of these …

2019

Purpose: To summarize existing knowledge and to understand individual response to radiation exposure, the MELODI Association together with CONCERT European Joint Programme has organized a workshop in March 2018 on radiation sensitivity and susceptibility.Methods: The workshop reviewed the current evidence on this matter, to inform the MELODI Strategic Research Agenda (SRA), to determine social and scientific needs and to come up with recommendations for suitable and feasible future research initiatives to be taken for the benefit of an improved medical diagnosis and treatment as well as for radiation protection.Results: The present paper gives an overview of the current evidence in this fie…

SU-FF-T-329: Monte Carlo Dosimetric Study of the Flexisource Ir-192 HDR Source

2006

Purpose:Brachytherapy with high dose rate (HDR) sources of 192 Ir is a usual practice in clinical brachytherapy today. The TG43 U1 update report recommends that accurate dose distribution data of the brachytherapysource in use should be obtained experimentally or by Monte Carlo (MC), to be used as input in the HDR Treatment Planning System (TPS). The purpose of this study is to obtain the dose rate distribution in liquid water media for the Flexisource HDR 192 Ir source (Isodose Control GmbH, Germany) using the Monte Carlo method to obtain the TG43 U1 parameters and the 2‐D rectangular dose rate table. Material and methods: The MC code GEANT4 (7.1 version) was used to estimate dose rate in …

WE-C-141-01: Research and Relevance of Brachytherapy Dose Calculation Advancements

2013

Research and Relevance of Brachytherapy Dose Calculation Advancements Organizer: Mark J. Rivard Moderator: Geoffrey S. Ibbott Speakers: Facundo Ballester, Asa Carlsson Tedgren, Firas Mourtada Brachytherapy dosimetry is undergoing a renaissance with the scrutiny of the AAPM TG‐43 dose calculation formalism and comparisons with alternate approaches such as the Monte Carlo method, the grid‐based Boltzmann solvers, and the collapsed‐cone technique. Treatment planning systems (TPS) using these more advanced, model‐based dose calculation algorithms (MBDCAs) are now available for clinical use. However, their accuracy and the preferred method for their use have not been established. Thus, it is imp…

Tube Housing Leakiness Radiation and Patient Related Radiation Protective Measures – Gonads Radiation Exposure from Panoramic Radiography

2009

The purpose of this study was to compare patient- and apparatus related radiation protective measures considering gonad radiation exposure at panoramic radiography. The local dose (yGv) in the region of the gonads of a male Alderson-Rando-Phantom was measured by the dosimeter Tol-F (Berthold Technology, Germany) during panoramic radiography (PR) by the digital Orthophos XG plus®(Sirona / Bensheim, Germany). Different radiation protective measures was investigated during constant exposure parameters. In the second part of the survey the same ionisation chamber recorded the scattered radiation at the gonads level of the none protected phantom at various case shielding. Without protection apro…

Oral Squamous Cell Carcinoma Associated with a Dental Implant: a case report and literature review

2011

Objectives: Prosthodontic rehabilitation using dental implants has become a common practice in dentistry at the present time. Although severe complications related to dental osseointegrated implants are uncommon, in recent years several cases of oral squamous cell carcinoma adjacent to dental implants have been published. Study Design: A 67-year-old edentulous woman developed an oral squamous cell carcinoma around right mandibular implant about 12 months after receiving dental implants. The treatments involve chemotherapy, explantation of the implants and radiotherapy. Result and Conclusions: The use of endosseous implants has been associated with a low risk for the development of cancer. H…

Effectiveness of semi-permeable dressings to treat radiation-induced skin reactions. A systematic review

2017

The aim of this systematic review is to assess the available evidence concerning the effectiveness of semi-permeable dressings, on the full range of skin reactions, related to radiation therapy in cancer patients, from local erythema to moist desquamation, including subjective symptoms such as pain, discomfort, itchiness, burning and the effect on daily life activities. The bibliographic search was carried out looking for Randomised Clinical Trials (RCTs) indexed in PubMed, Cinhal, Cochrane plus and Biblioteca Nacional de Salud, published in the English and Spanish language, between 2010 and 2015. Data extraction and evaluation of study quality was undertaken by peer reviewers using the Cri…

Preoperative chemoradiotherapy for oesophageal cancer: a systematic review and meta-analysis

2004

Background: The benefit of neoadjuvant chemoradiotherapy in oesophageal cancer has been extensively studied but data on survival are still equivocal. Objective: To assess the effectiveness of chemoradiotherapy followed by surgery in the reduction of mortality in patients with resectable oesophageal cancer. Methods: Computerised bibliographic searches of MEDLINE and CANCERLIT (1970–2002) were supplemented with hand searches of reference lists. Study selection: Studies were included if they were randomised controlled trials (RCTs) comparing preoperative chemoradiotherapy plus surgery with surgery alone, and if they included patients with resectable histologically proven oesophageal cancer wit…