MEGURATH
MEGURATH - Metrology Guided Radiotherapy
MEGURATH ("Metrology Guided Radiation Therapy")
MEGURATH is a UK project, funded by the EPSRC, consisting of a consortium of three partners, all from the North-West of England;
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The Christie Hospital Manchester - NWMP (EP/D078415/1)
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University Of Central Lancashire (UCLAN) - The ADSIP Centre (EP/D077540/1)
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Liverpool John Moores University - GERI (EP/D077702/1)
MEGURATH is the third and latest project in the field of targeting in radiotherapy that has been carried out by GERI at Liverpool John Moores University.
It builds on and extends the work carried out in the two European projects INFOCUS and ARROW in order to create a new generation of 3D optical sensors for pateint position monitoring.
Visit the dedicated MEGURATH Website.
Read a press release from UCLAN announcing the start of MEGURATH. It can be found on page 18 of the January 2007 UCLAN Research Newsletter.
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‡Image Courtesy Of Elekta Ltd.
Currently, when radiotherapy treatment is in progress and radiation is being actively directed at the tumour, there is no effective dynamic monitoring of the patient's position or internal anatomy. This means that the carefully and precisely planned treatment is actually delivered in a manner that is effectively blind to any bulk or dynamic movements of the patient from the internal/external body position recorded in pre-treatment scans. This situation persists, despite complex new treatments and "Image Guided Radiotherapy" (IGRT), which now includes cone beam imaging (CBI). IGRT combines a radiotherapy treatment machine, essentially a linear accelerator producing high energy X-Rays, with a kilovoltage X-Ray imaging system. This at least enables tomographic imaging to take place whilst the patient is in position on the treatment table, rather than on a similar, but different, separate X-Ray imaging simulator or CT scanner. However, measurements are still not performed during actual treatment delivery, instead imaging may be achieved 'just before' treatment.
MEGURATH seeks to move from current state-of-the-art image guided radiotherapy (IGRT), towards "Metrology Guided Radiotherapy" (MGRT), where the patient will be externally measured in 3D using the optical sensor system, tomographically imaged and modelled during the actual process of treatment delivery.
MEGURATH will use non-invasive, radiation-free, real-time 3D patient positional monitoring based on optoelectronic sensors using structured light to map the 3D body surface. A prototype system, with unrivalled performance, has been successfully piloted by the investigators in a treatment room at the Christie Hospital. This will be developed to include radical concepts of multi-colour, adaptive sensing, where the structured light projected onto the body surface is first pre-adapted to the shape information available in patient's CT planning scan and then refined during use.
The MEGURATH optical sensors will be synchronised with novel low radiation dose CBI system, based on acquiring images of the patient as the treatment gantry rotates, in-between treatment beams. In a feedback loop, the CBI will then be optimally corrected for measured motion using the optical sensor system.
Reconstructive imaging will then be combined with dynamic deformation modelling, to quantify changes in the shapes and positions of the tumour and nearby organs. Pilot work using sensor measurements to deform treatment plans has already been carried out by the investigators. Extending this approach across the irradiated part of the body will make it possible to describe the shape changes that actually occurred in the patient during irradiation. This will be the first time that a point by point model of the patient during treatment has been constructed from live measurements. In turn, this will finally make it possible to use radiobiology to calculate the probabilities of tumour cure and complications for the treatment actually delivered, and to compare this with the treatment that was planned.
