| Autor: |
Jeffrey F. Williamson, Mitchell S. Anscher, Elizabeth Weiss, Mirek Fatyga, Zhouping Wei, Martin J. Murphy, Timothy J. Wallace |
| Rok vydání: |
2008 |
| Předmět: |
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| Zdroj: |
Medical Physics. 35:1145-1153 |
| ISSN: |
0094-2405 |
| DOI: |
10.1118/1.2837292 |
| Popis: |
Received 20 August 2007; revised 10 December 2007; accepted for publication 2 January 2008;published 27 February 2008Purpose: To measure the sensitivity of deformable image registration to image noise. Deformableimage registration can be used to map organ contours and other treatment planning data from oneCT to another. These CT studies can be acquired with either conventional fan-beam CT systems ormore novel cone-beam CT techniques. However, cone-beam CT images can have higher noiselevels than fan-beam CT, which might reduce registration accuracy. We have investigated the effectof image quality differences on the deformable registration of fan-beam CTs and CTs with simu-lated cone-beam noise. Method: Our study used three CT studies for each of five prostate patients.Each CT was contoured by three experienced radiation oncologists. For each patient, one CT wasdesignated the source image and the other two were target images.Adeformable image registrationprocess was used to register each source CT to each target CT and then transfer the manually drawntreatment planning contours from the source CT to the target CTs. The accuracy of the automati-cally transferred contours and thus of the deformable registration process was assessed by com-paring them to the manual contours on the target CTs, with the differences evaluated with respectto interobserver variability in the manual contours. Then each of the target CTs was modified toinclude increased noise characteristic of cone-beam CT and the tests were repeated. Changes inregistration accuracy due to increased noise were detected by monitoring changes in the automati-cally transferred contours. Results: We found that the additional noise caused no significant loss ofregistration accuracy at magnitudes that exceeded what would normally be found in an actualcone-beam CT. Summary: We conclude that noise levels in cone-beam CTs that might reducemanual contouring accuracy do not reduce image registration and automatic contouringaccuracy. © |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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