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Purpose: |
A challenge for fractionated stereotactic radiotherapy (SRT) is to develop an accurate, precise, and clinically feasible system for patient refixation because a small positioning error may result in both the failure of tumor cure and the irradiating of normal brain in treatment of small brain lesions. Presently, we have not found a satisfactory refixation technique. Frame-based patient positioning [1-5] for stereotactic radiosurgery (SRS) is
infeasible for fractionated SRT because the patient cannot tolerate the invasive frame for weeks of treatment. Frame-less two-dimensional (2D) image-based refixations [6-19] are generally cumbersome and imprecise. Noninvasive patient fixation using a relocatable head holder [20-24] introduces additional uncertainty during the device reattachment.
The volumetric changes during the radiotherapy for head&neck, breast, and chest wall tumors create new challenge for accurate dose delivery in radiotherapy.
The specific aims of this research are:
1. To measure the accuracy and precision of the 3D-video images for the surface of the patient’s head and other part of body.
2. To determine the accuracy of reference surface created from CT-images;
3. To verify the assumption of human head (or parts of human head) as a rigid object;
4. To develop a fast and accurate 3D-surface fitting (mapping) algorithm;
5. To modify or rebuild the patient immobilization and adjustment system for the surface guided refixation;
6. To evaluate the clinical feasibility by simulating possible head, skin, and eye motion
and skin colors;
7. To explore the visual servo concept for automatically position correction with computer-aided system;
8. To establish a clinical application and quality assurance procedure. |
