DOSIMETRIC IMPACT OF ONLINE CORRECTION VIA CONE-BEAM CT-BASED IMAGE GUIDANCE FOR STEREOTACTIC LUNG RADIOTHERAPY

作者：Galerani Ana Paula; Grills Inga^*; Hugo Geoffrey; Kestin Larry; Mohammed Nasiruddin; Chao K Kenneth; Suen Andrew; Martinez Alvaro; Yan Di

来源：International Journal of Radiation Oncology, Biology, Physics, 2010, 78(5): 1571-1578.

DOI：10.1016/j.ijrobp.2010.02.012

• Cone-beam computed tomography
• Image-guided radiotherapy
• Lung cancer
• Dosimetry
• Stereotactic radiotherapy

Purpose To evaluate the dosimetric Impact of online cone-beam computed tomography (CBCT) guided correction in lung stereotactic body radiation therapy (SBRT)
Methods and Materials Twenty planning and 162 CBCT images from 20 patients undergoing lung SBRT were analyzed The precorrection CBCT (CBCT after patient setup, no couch correction) was registered to planning CT using soft tissue, couch shift was applied, with a second CBCT for verification (postcorrection CBCT) Targets and normal structures were delineated on CBCTs gross tumor volume (GTV), clinical target volume (CTV), cord, esophagus, lung, proximal bronchial tree, and aorta Dose distributions on all organs manifested on each CBCT were compared with those planned on the CT
Results Without CBCT guided target position correction, target dose reduced with respect to treatment plan Mean and standard deviation of treatment dose discrepancy from the plan were -3 2% (49%), -2 1% (4 4%), -6 1% (10 7%), and -3 5% (7%) for GTV D(99%), GTV D(95%), CTV D(99%), and CTV D(95%), respectively With CBCT correction, the results were -0 4% (2 6%), 0 1% (1 7%), -0 3% (4 2%), and 0 5% (3%) Mean and standard deviation of the difference in normal organ maximum dose were 2 2% (6 5%) before correction and 2 4% (59%) after correction for esophagus, 6 1% (14 1%) and 3 8% (8 1%) for cord, 3 1% (17 5 %) and 6 2% (9 8%) for proximal bronchial tree, and 17 7% (19 5%) and 14 1% (17%) for aorta
Conclusion Online CBCT guidance improves the accuracy of target dose delivery for lung

• 出版日期2010-12-1