Abstract
We have previously reported that computer-controlled table repositioning can increase the reproducibility of patient setup in 2-D using a megavoltage imager and bony anatomy as a reference of position. This investigation was extended to daily 3-D localization of soft tissue structures ("target of the day" treatment). Research to date has involved liver (under ventilatory immobilization) and prostate patients. Both protocols involve aligning the specified target to the reference position (determined via CT) using a diagnostic imager and alignment software. The liver position is determined by the position of the diaphragm and the spine, the prostate target is automatically localized and positioned through computer-based extraction of 3 implanted gold markers. Adjustments to correct target position are executed using a computer-controlled table. Measuring the residual offset of the target after the corrective action determines the accuracy of measurement and table adjustment, however this uncertainty is also influenced by organ motion between images. For the prostate protocol, the accuracy of the computer-controlled target repositioning is dx: 056 mm (σ = 3.69 mm), dy: 2.74 mm (σ = 3.87 mm), dz: 2.38 (σ = 4.5 mm) after 24 treatment fractions. For the liver protocol, the accuracy is dx: -0.7 mm (σ = 1.67 mm), dy: -0.9 mm (σ = 1.89 mm), dz: 1.0 mm (σ = 3.18 mm) after 23 treatment fractions. The extra time necessary to image, align, and adjust the target has also been calculated. The average time for the localization and subsequent verification is 12.2 minutes (σ = 5.7 min).
Original language | English (US) |
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Pages (from-to) | 2122-2123 |
Number of pages | 2 |
Journal | Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings |
Volume | 3 |
State | Published - 2000 |
Externally published | Yes |
Event | 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society - Chicago, IL, United States Duration: Jul 23 2000 → Jul 28 2000 |
Keywords
- Computer-controlled table
- Diagnostic imaging
- Patient setup adjustment
- Target of the day
ASJC Scopus subject areas
- Signal Processing
- Biomedical Engineering
- Computer Vision and Pattern Recognition
- Health Informatics