%0 Journal Article
%T Recent advances in radiotherapy
%A SA Bhide
%A CM Nutting
%J BMC Medicine
%D 2010
%I BioMed Central
%R 10.1186/1741-7015-8-25
%X The delivery of radiotherapy has changed significantly over the last few decades. We have moved from conventional radiotherapy using simple rectangular treatment fields to increasingly conformal radiotherapy techniques such as three dimensional conformal radiotherapy (3D-CRT) and intensity modulated radiotherapy (IMRT). These changes in the delivery of radiotherapy have come about as result of trying to improve the delivered dose to tumour bearing tissues, and reduce irradiation of organs at risk (OARs), hence improving the therapeutic ratio of the radiation treatment. The radiation dose is prescribed to the planning target volume (PTV), which includes the gross tumour volume (GTV) plus areas of microscopic spread (clinical target volume, CTV) and a margin around it to account for the systematic and random errors plus physiological organ changes that occur during the treatment planning and delivery process [1,2]. Using three-dimensional conformal radiotherapy to deliver a radical dose to the PTV, results in a significant dose to the OARs. There is robust evidence from several tumour sites, such as head and neck, prostate and lung, supporting dose-escalation and/or altered fractionation for improved outcomes [3-6]. Reducing the dose to the OARs using techniques such as IMRT and reducing the size of the PTV using image guided radiotherapy (IGRT) enables radiation dose-escalation to be done, to improve the treatment outcomes.IMRT is an advanced approach to three-dimensional treatment planning and conformal therapy. It optimizes the delivery of irradiation to irregularly-shaped volumes and has the ability to produce concavities in radiation treatment volumes. IMRT can be delivered using linear accelerators with static multi-leaf collimators (MLC, step and shoot IMRT) or dynamic leaf MLCs, tomotherapy machines or volumetric arc modulated therapy (VMAT). The simultaneous boost IMRT allows for varying doses to be delivered to various target volumes in a single phase and ob
%U http://www.biomedcentral.com/1741-7015/8/25