- 作者：Shinichiro Mori ; PhD ; shinshin@nirs.go.jp" class="auth_mail" title="E-mail the corresponding author ; Masataka Karube ; MD ; Toshiyuki Shirai ; PhD ; Minoru Tajiri ; RT ; Takuro Takekoshi ; RT ; Kentaro Miki ; PhD ; Yurika Shiraishi ; RT ; Katsuyuki Tanimoto ; PhD ; Kouichi Shibayama ; RT ; Shigeo Yasuda ; MD ; Naoyoshi Yamamoto ; MD ; Shigeru Yamada ; MD ; Hiroshi Tsuji ; MD ; Koji Noda ; PhD ; Tadashi Kamada ; MD
- 刊名：International Journal of Radiation Oncology*Biology*Physics
- 出版年：2016
- 出版时间：1 May 2016
- 年：2016
- 卷：95
- 期：1
- 页码：258-266
- 全文大小：1120 K
Methods and Materials
A total of 10 patients with tumors of the lung and liver participated in the first clinical trials at our center. Treatment planning was conducted with 4-dimensional computed tomography (4DCT) under free-breathing conditions. The planning target volume (PTV) was calculated by adding a 2- to 3-mm setup margin outside the clinical target volume (CTV) within the gating window. The treatment beam was on when the CTV was within the PTV. Tumor position was detected in real time with a markerless tumor tracking system using paired x-ray fluoroscopic imaging units.
Results
The patient setup error (mean ± SD) was 1.1 ± 1.2 mm/0.6 ± 0.4°. The mean internal gating accuracy (95% confidence interval [CI]) was 0.5 mm. If external gating had been applied to this treatment, the mean gating accuracy (95% CI) would have been 4.1 mm. The fluoroscopic radiation doses (mean ± SD) were 23.7 ± 21.8 mGy per beam and less than 487.5 mGy total throughout the treatment course. The setup, preparation, and irradiation times (mean ± SD) were 8.9 ± 8.2 min, 9.5 ± 4.6 min, and 4.0 ± 2.4 min, respectively. The treatment room occupation time was 36.7 ± 67.5 min.
Conclusions
Internal gating had a much higher accuracy than external gating. By the addition of a setup margin of 2 to 3 mm, internal gating positional error was less than 2.2 mm at 95% CI.