Insertion and fixation of fiducial markers for setup and tracking of lung tumors in radiotherapy
- First Department of Medicine, Hokkaido University School of Medicine, Sapporo (Japan)
- Department of Radiology, Hokkaido University School of Medicine, Sapporo (Japan)
- Department of Medicine, Iwamizawa Municipal Hospital, Iwamizawa (Japan)
- Department of Respiratory Diseases, Sapporo City General Hospital, Sapporo (Japan)
- Department of Medical Oncology, Hokkaido University Graduate School of Medicine, Sapporo (Japan)
Purpose: Internal 1.5-mm fiducial markers were used in real-time tumor-tracking radiotherapy (RT) for lung cancer. The fixation rate of the markers using the bronchial insertion technique, reliability of the setup using markers around the target volume, dislocation of the markers after real-time tumor-tracking RT, and long-term toxicity of marker insertion were investigated. Methods and Materials: Between July 2000 and April 2004, 154 gold markers were inserted into 57 patients with peripheral lung cancer. The distances between the implanted markers in 198 measurements in 71 setups in 11 patients were measured using two sets of orthogonal diagnostic X-ray images of the real-time tumor-tracking RT system. The distance between the markers and the chest wall was also measured in a transaxial CT image on 186 occasions in 48 patients during treatment planning and during follow-up. The median treatment time was 6 days (range, 4-14 days). Results: In 115 (75%) of the 154 inserted markers, the gold marker was detected throughout the treatment period. In 122 markers detected at CT planning, 115 (94%) were detected until the end of treatment. The variation in the distances between the implanted markers was within {+-}2 mm in 95% and {+-}1 mm in 80% during treatment. The variation in the distances between the implanted markers was >2 mm in at least one direction in 9% of the setups for which reexamination with a CT scan was indicated. The fixation rate in the left upper lobe was lower than in the other lobes. A statistically significant relationship was found between a shorter distance between the markers and the chest wall and the fixation rate, suggesting that the markers in the smaller bronchial lumens fixed better than those in the larger lumens. A learning curve among the endoscopists was suggested in the fixation rate. The distance between the markers and the chest wall changed significantly within a median of 44 days (range, 16-181 days) after treatment. Conclusion: The fixation of markers into the bronchial tree was useful for the setup for peripheral lung cancer and had an accuracy of {+-}2 mm during the 1-2-week treatment period. The relationship between the markers and tumor can change significantly after 2 weeks, suggesting that adaptive four-dimensional RT is required.
- OSTI ID:
- 20788237
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 63, Issue 5; Other Information: DOI: 10.1016/j.ijrobp.2005.04.024; PII: S0360-3016(05)00713-3; Copyright (c) 2005 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
Similar Records
Optimization of the x-ray monitoring angle for creating a correlation model between internal and external respiratory signals
Implantation and Stability of Metallic Fiducials Within Pulmonary Lesions