نتایج جستجو برای: megavoltage radiotherapy

تعداد نتایج: 62462  

Journal: :The British journal of radiology 2014
W B Hyland S J McMahon K T Butterworth A J Cole R B King K M Redmond K M Prise A R Hounsell C K McGarry

OBJECTIVE The aim of this study was to investigate the effect of pre-treatment verification imaging with megavoltage X-rays on cancer and normal cell survival in vitro and to compare the findings with theoretically modelled data. Since the dose received from pre-treatment imaging can be significant, the incorporation of this dose at the planning stage of treatment has been suggested. METHODS ...

Journal: :Medical physics 2012
M Mera L Pereira E Meilán F Del Moral A Teijeiro M Salgado B Andrade F Gomez V Fuentes-Vázquez J Caruncho A Medina

PURPOSE The most common material for shielding is concrete, which can be made using various materials of different densities as aggregates. New techniques in radiotherapy, as IMRT and VMAT, require more monitor units and it is important to develop specifically designed shielding materials. METHODS Arraela S.L. has developed new concrete (CONTEK®-RFH2), which is made from an arid with a high p...

Journal: :Medical physics 2011
Alexandra Quinn Lois Holloway Dean Cutajar Nicholas Hardcastle Anatoly Rosenfeld Peter Metcalfe

PURPOSE Cone beam computed tomography (CBCT) is fast becoming standard on modern linear accelerators. CBCT increases the dose to regions within and outside the treatment field, potentially increasing secondary cancer induction and toxicity. This study quantified megavoltage (MV) CBCT skin dose and compared it to skin dose delivered during standard tangential breast radiotherapy. METHOD Dosime...

2018

This clinical practice guideline is a set of evidence-based recommendations to assist radiographers, radiotherapy nurses, and the wider radiotherapy workforce, in advising patients how to care for their skin while undergoing a course of radical external beam radiotherapy (excluding proton therapy). It has been developed systematically using the best available evidence from research and expert o...

Journal: :Physics in medicine and biology 1992
D I Thwaites J R Williams E G Aird S C Klevenhagen P C Williams

A dosimetry intercomparison has been carried out for all 64 radiotherapy centres in the UK. Doses were measured with an ionization chamber in an epoxy resin water-substitute phantom of relatively simple geometry. Reference-point measurements were made for all MV photon beams. For 61 Co-60 beams, a mean ratio of measured-to-stated dose of 1.002 was observed with a standard deviation of 0.014, wh...

2014
Wei Loong Jong Jeannie Hsiu Ding Wong Ngie Min Ung Kwan Hoong Ng Gwo Fuang Ho Dean L. Cutajar Anatoly B. Rosenfeld

In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET-based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water eq...

2011
Volker Rudat Mohamed Hammoud Yogin Pillay Abdul Aziz Alaradi Adel Mohamed Saleh Altuwaijri

PURPOSE The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin, SM). METHODS AND MATERIALS Alignment data of 148 patients treated with inversed planned intensit...

Journal: :Physics in medicine and biology 2008
Eric E Klein Milos Vicic Chang-Ming Ma Daniel A Low Robert E Drzymala

Treating shallow tumors with a homogeneous dose while simultaneously minimizing the dose to distal critical organs remains a challenge in radiotherapy. One promising approach is modulated electron radiotherapy (MERT). Due to the scattering properties of electron beams, the commercially provided secondary and tertiary photon collimation systems are not conducive for electron beam delivery when s...

Journal: :Medical dosimetry : official journal of the American Association of Medical Dosimetrists 1999
P Keall F Monti di Sopra W Beckham G Delaney

The dose distributions for a patient with cancer involving the sternum were calculated for both a kilovoltage x-ray beam and a megavoltage electron beam. The minimum target dose and dose uniformity over the target volume were significantly better using electrons (90%-101%) than kilovoltage x-rays (68%-119%). The calculated lung dose and integral patient dose were also less for electrons than ki...

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