Paper
28 May 2001 Multimodality image integration for radiotherapy treatment: an easy approach
Andres Santos, Javier Pascau, Manuel Desco, Juan A. Santos, Felipe A. Calvo, Carlos Benito, Rafael Garcia-Barreno
Author Affiliations +
Abstract
The interest of using combined MR and CT information for radiotherapy planning is well documented. However, many planning workstations do not allow to use MR images, nor import predefined contours. This paper presents a new simple approach for transferring segmentation results from MRI to a CT image that will be used for radiotherapy planning, using the same original CT format. CT and MRI images of the same anatomical area are registered using mutual information (MI) algorithm. Targets and organs at risk are segmented by the physician on the MR image, where their contours are easy to track. A locally developed software running on PC is used for this step, with several facilities for the segmentation process. The result is transferred onto the CT by slightly modifying up and down the original Hounsfield values of some points of the contour. This is enough to visualize the contour on the CT, but does not affect dose calculations. The CT is then stored using the original file format of the radiotherapy planning workstation, where the technician uses the segmented contour to design the correct beam positioning. The described method has been tested in five patients. Simulations and patient results show that the dose distribution is not affected by the small modification of pixels of the CT image, while the segmented structures can be tracked in the radiotherapy planning workstation-using adequate window/level settings. The presence of the physician is not requires at the planning workstation, and he/she can perform the segmentation process using his/her own PC. This new approach makes it possible to take advantage from the anatomical information present on the MRI and to transfer the segmentation to the CT used for planning, even when the planning workstation does not allow to import external contours. The physician can draw the limits of the target and areas at risk off-line, thus separating in time the segmentation and planning tasks and increasing the efficiency.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Andres Santos, Javier Pascau, Manuel Desco, Juan A. Santos, Felipe A. Calvo, Carlos Benito, and Rafael Garcia-Barreno "Multimodality image integration for radiotherapy treatment: an easy approach", Proc. SPIE 4319, Medical Imaging 2001: Visualization, Display, and Image-Guided Procedures, (28 May 2001); https://doi.org/10.1117/12.428119
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Cited by 1 scholarly publication.
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KEYWORDS
Image segmentation

Computed tomography

Magnetic resonance imaging

Radiotherapy

Tumors

Image registration

Image processing

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