Three-dimensional position determination of catheters for the purpose of Brachytherapy
conference paper
Treatment planning in brachytherapy depends heavily on the accurate localization of markers in a catheter implant. We are developing an interactive system to combine the image information of biplane X-ray images to reconstruct the 3D marker positions. Current systems ask the user to identify all corresponding markers in both images manually. Especially in cases where multiple, eventually crossing catheters are present this is very time consuming and difficult as markers that are visible in one image may be hidden in the other image. To improve the procedure of marker detection we apply image-processing techniques. We investigate two approaches. One is based on 3D snakes. This is a model-based technique that is not sensitive to noise or ambiguities in the image. After the user has given a number of corresponding points per catheter, the system automatically detects the complete catheter and determines all 3D-marker positions. The second approach uses edge detection in a small region of interest (ROD. In both cases, knowledge about the catheter is used to guide the marker detection algorithm. The user has to examine the result visually. In case of erroneous marker detection the user can move, add or delete single marker points. To be able to judge the accuracy of the reconstruction it is necessary to locate possible error sources. For an accurate reconstruction of the catheter positions it is important to know the exact geometry of the imaging system. With a mathematical model the influence of uncertainties in parameters on the reconstruction result is studied.
TNO Identifier
235389
ISSN
0277786X
Publisher
Society of Photo-Optical Instrumentation Engineers SPIE
Source title
Medical Imaging 2000, Image Processing, 14-17 February 2000, San Diego, CA, USA
Collation
8 p.
Place of publication
Bellingham, WA, USA
Files
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