Paper
1 June 2005 Parallel beam optical tomography apparatus for 3D radiation dosimetry
Author Affiliations +
Abstract
Since the discovery of X rays radiotherapy has had the same aim - to deliver a precisely measured dose of radiation to a defined tumour volume with minimal damage to surrounding healthy tissue. Recent developments in radiotherapy such as intensity modulated radiotherapy (IMRT) can generate complex shapes of dose distributions. Until recently it has not been possible to verify that the delivered dose matches the planned dose. However, one often wants to know the real three-dimensional dose distribution. Three-dimensional radiation dosimeters have been developed since the early 1980s. Most chemical formulations involve a radiosensitive species immobilised in space by gelling agent. Magnetic Resonance Imaging (MRI) and optical techniques have been the most successful gel scanning techniques so far. Optical techniques rely on gels changing colour once irradiated. Parallel beam optical tomography has been developed at the University of Surrey since the late 1990s. The apparatus involves light emitting diode light source collimated to a wide (12cm) parallel beam. The beam is attenuated or scattered (depending on the chemical formulation) as it passes through the gel. Focusing optics projects the beam onto a CCD chip. The dosimeter sits on a rotation stage. The tomography scan involves continuously rotating the dosimeter and taking CCD images. Once the dosimeter has been rotated over 180 degrees the images are processed by filtered back projection. The work presented discusses the optics of the apparatus in more detail.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nikola Krstajic and Simon J. Doran "Parallel beam optical tomography apparatus for 3D radiation dosimetry", Proc. SPIE 5823, Opto-Ireland 2005: Imaging and Vision, (1 June 2005); https://doi.org/10.1117/12.604973
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KEYWORDS
Charge-coupled devices

Collimation

Optical tomography

Scattering

Spatial resolution

Radiotherapy

Refractive index

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