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Precision Imaging in Radiotherapy

Abstract:

Delivering exact radiation doses through image-guided radiation therapy to specific areas of a tumour demands ever increasing accuracy from the radiotherapy solutions. Currently, this need for precision images is being met by Agfa’s Computed Radiography (CR) solution. A digital simulation and portal imaging system for both low- and high-dose applications, it handles low- and high-energy X-rays. It is capable of acquiring radiographic quality images in a radiotherapy environment using CR technology.This enables the acquisition of digital images, which, in comparison with conventional film, results in higher contrast images. Launched in early 2005, this solution is the result of Agfa building upon its worldwide standard technologies in general radiation and its experience in developing unique solutions for other specialist markets such as orthopaedics, paediatrics and mammography.

How it Works
An X-ray image is recorded onto Agfa’s unique image plate, which is held in a dust-proof cassette.This image plate is coated with a phosphor layer that is sensitive to stimulation by incoming X-ray photons. Following exposure, the cassette is inserted into the Agfa CR 25.0 digitiser, which reads the information via a laser beam.

This activates the phosphor grains on the image plate to release energy in the form of light. This light is then collected as a digital image and processed – with Agfa’s patented MusicaTM image processing software – to obtain an exact digital image for display. The digital image can then be adjusted or reprocessed using Agfa’s CR Quality System (QS), a dedicated software package to enhance the imaging quality procedures within the department – something that has, until now, only been available in more expensive radiotherapy application areas. Once any adjustments have been made, the images can be made available on any hospital network via Digital Imaging and Communications in Medicine (DICOM) or by printing onto film using Agfa’s DRYSTARTM 5300.

Dedicated Plates and Cassettes
At the heart of the newly designed CR Radiotherapy Solution are cassettes that have been thoroughly evaluated in radiotherapy departments around the world.These cassettes, with their tungsten internal filter – a system patented by Agfa – provide significantly enhanced detection, while the lighter weight of the casing makes them more ergonomic and, therefore, more flexible for image manipulation when compared with others currently on the market. The CR radiotherapy high-dose cassettes offer optimal image quality at an extremely wide dose response of greater than 400 monitor units and are available for both high- and low-dosage applications. The CR RT low-dose cassettes for low-dose CR portal imaging provide excellent image quality in the low-dose range.