1. Three-dimensional intrafractional motion of breast during tangential breast irradiation monitored with high-sampling frequency using a real-time tumor-tracking radiotherapy system.
- Author
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Kinoshita R, Shimizu S, Taguchi H, Katoh N, Fujino M, Onimaru R, Aoyama H, Katoh F, Omatsu T, Ishikawa M, and Shirato H
- Subjects
- Adult, Aged, Body Mass Index, Female, Gold, Humans, Middle Aged, Prostheses and Implants, Radiotherapy instrumentation, Regression Analysis, Breast Neoplasms radiotherapy, Computer Systems, Movement, Respiration
- Abstract
Purpose: To evaluate the three-dimensional intrafraction motion of the breast during tangential breast irradiation using a real-time tracking radiotherapy (RT) system with a high-sampling frequency., Methods and Materials: A total of 17 patients with breast cancer who had received breast conservation RT were included in this study. A 2.0-mm gold marker was placed on the skin near the nipple of the breast for RT. A fluoroscopic real-time tumor-tracking RT system was used to monitor the marker. The range of motion of each patient was calculated in three directions., Results: The mean +/- standard deviation of the range of respiratory motion was 1.0 +/- 0.6 mm (median, 0.9; 95% confidence interval [CI] of the marker position, 0.4-2.6), 1.3 +/- 0.5 mm (median, 1.1; 95% CI, 0.5-2.5), and 2.6 +/- 1.4 (median, 2.3; 95% CI, 1.0-6.9) for the right-left, craniocaudal, and anteroposterior direction, respectively. No correlation was found between the range of motion and the body mass index or respiratory function. The mean +/- standard deviation of the absolute value of the baseline shift in the right-left, craniocaudal, and anteroposterior direction was 0.2 +/- 0.2 mm (range, 0.0-0.8 mm), 0.3 +/- 0.2 mm (range, 0.0-0.7 mm), and 0.8 +/- 0.7 mm (range, 0.1-1.8 mm), respectively., Conclusion: Both the range of motion and the baseline shift were within a few millimeters in each direction. As long as the conventional wedge-pair technique and the proper immobilization are used, the intrafraction three-dimensional change in the breast surface did not much influence the dose distribution.
- Published
- 2008
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