Cone-Beam Computed Tomographic Image Guidance for Lung Cancer Radiation Therapy
- Radiation Medicine Program, Princess Margaret Hospital, Toronto, ON (Canada)
Purpose: To determine the geometric accuracy of lung cancer radiotherapy using daily volumetric, cone-beam CT (CBCT) image guidance and online couch position adjustment. Methods and Materials: Initial setup accuracy using localization CBCT was analyzed in three lung cancer patient cohorts. The first (n = 19) involved patients with early-stage non-small-cell lung cancer (NSCLC) treated using stereotactic body radiotherapy (SBRT). The second (n = 48) and third groups (n = 20) involved patients with locally advanced NSCLC adjusted with manual and remote-controlled couch adjustment, respectively. For each group, the couch position was adjusted when positional discrepancies exceeded {+-}3 mm in any direction, with the remote-controlled couch correcting all three directions simultaneously. Adjustment accuracy was verified with a second CBCT. Population-based setup margins were derived from systematic ({sigma}) and random ({sigma}) positional errors for each group. Results: Localization imaging demonstrates that 3D positioning errors exceeding 5 mm occur in 54.5% of all delivered fractions. CBCT reduces these errors; post-correction {sigma} and {sigma} ranged from 1.2 to 1.9 mm for Group 1, with 82% of all fractions within {+-}3 mm. For Group 2, {sigma} and {sigma} ranged between 0.8 and 1.8 mm, with 76% of all treatment fractions within {+-}3 mm. For Group 3, the remote-controlled couch raised this to 84%, and {sigma} and {sigma} were reduced to 0.4 to 1.7 mm. For each group, the postcorrection setup margins were 4 to 6 mm, 3 to 4 mm, and 2 to 3 mm, respectively. Conclusions: Using IGRT, high geometric accuracy is achievable for NSCLC patients, potentially leading to reduced PTV margins, improved outcomes and empowering adaptive radiation therapy for lung cancer.
- OSTI ID:
- 21172648
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 73, Issue 3; Other Information: DOI: 10.1016/j.ijrobp.2008.08.059; PII: S0360-3016(08)03503-7; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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