目的：应用千伏级锥形束CT （kV级CBCT）图像引导放疗技术评估肝癌患者分次放疗间位置的变化。方法15例肝癌患者，每例患者在放疗前行CBCT扫描，每周1～3次，共获取121幅 CBCT图像。离线下以肝脏、椎体外轮廓分别为参照物完成CBCT图像...目的：应用千伏级锥形束CT （kV级CBCT）图像引导放疗技术评估肝癌患者分次放疗间位置的变化。方法15例肝癌患者，每例患者在放疗前行CBCT扫描，每周1～3次，共获取121幅 CBCT图像。离线下以肝脏、椎体外轮廓分别为参照物完成CBCT图像与计划CT的配准，将配准结果定义为分次放疗间肝脏及椎体位置的变化，将两者配准结果的差值定义为肝脏相对于椎体位置的变化，分别予以评估。结果分次放疗间在三维方向，肝脏位移的绝对值以上下方向最大6.3 mm （0～19.3 mm）、左右方向次之2.3 mm（0～16.0 mm）、前后方向最小1.5 mm （0～7.6 mm）（P＜0.001）；椎体位移的绝对值以上下方向最大6.0 mm （0～18.0 mm）、左右方向次之3.0 mm （0～16.0 mm）、前后方向最小2.0 mm （0～10.0 mm）（P＜0.05）；肝脏相对于椎体位移的绝对值以上下方向最大4.8 mm （0.1～19.3 mm）、左右方向次之2.0 mm （0～8.6 mm）、上下方向最小1.4 mm （0～10.3 mm）（P＜0.001）。若通过配准椎体校正患者位置，放疗时左右、上下、前后方向肝脏位移的绝对值可能增大，可能性分别为39.7％、42.1％、43.0％。结论椎体不适于作为肝癌图像引导放疗的参照物。展开更多
Objective The aim of this study was to investigate tumor volume changes with kilovoltage cone-beam computed tomography （kV-CBCT） and their dosimetric consequences for non-operative lung cancer during intensity-modul...Objective The aim of this study was to investigate tumor volume changes with kilovoltage cone-beam computed tomography （kV-CBCT） and their dosimetric consequences for non-operative lung cancer during intensity-modulated radiotherapy （IMRT） or fractionated stereotactic radiotherapy. Methods Eighteen patients with non-operative lung cancer who received IMRT consisting of 1.8-2.2 Gy/fraction and five fractions per week or stereotactic radiotherapy with 5-8 Gy/fraction and three fractions a week were studied, kV-CBCT was performed once per week during IMRT and at every fraction during stereotactic radiotherapy. The gross tumor volume （GTV） was contoured on the kV-CBCT images, and adaptive treatment plans were created using merged kV-CBCT and primary planning computed tomogra- phy image sets. Tumor volume changes and dosimetric parameters, including the minimum dose to 95% （D95） or 1% （D1） of the planning target volume （PTV）, mean lung dose （MLD）, and volume of lung tissue that received more than 5 （Vs）, 10 （Vl0）, 20 （V20）, and 30 （V30） Gy were retrospectively analyzed. Results The average maximum change in GTV observed during IMRT or fractionated stereotactic radio- therapy was -25.85% （range, -13.09% --56.76%）. The D95 and Dr of PTV for the adaptive treatment plans in all patients were not significantly different from those for the initial or former adaptive treatment plans. In patients with tumor volume changes of 〉20% in the third or fourth week of treatment during IMRT, adap- tive treatment plans offered clinically meaningful decreases in MLD and V5, V10, V20, and V30; however, in patients with tumor volume changes of 〈 20% in the third or fourth week of treatment as well as in patients with stereotactic radiotherapy, there were no significant or clinically meaningful decreases in the dosimetric parameters. Conclusion Adaptive treatment planning for decreasing tumor volume during IMRT may be beneficial for patients who experience tumor volume changes of 〉20% in the third or fourth week of treatment.展开更多
Purpose: To investigate the feasibility of applying ANOVA newly proposed by Yukinori to verify the setup errors, PTV (Planning Target Volume) margins, DVH for lung cancer with SBRT. Methods: 20 patients receiving SBRT...Purpose: To investigate the feasibility of applying ANOVA newly proposed by Yukinori to verify the setup errors, PTV (Planning Target Volume) margins, DVH for lung cancer with SBRT. Methods: 20 patients receiving SBRT to 50 Gy in 5 fractions with a Varian iX linear acceleration were selected. Each patient was scanned with kV-CBCT before the daily treatment to verify the setup position. Two other error calculation methods raised by Van Herk and Remeijer were also compared to discover the statistical difference in systematic errors (Σ), random errors (σ), PTV margins and DVH. Results: Utilizing two PTV margin calculation formulas (Stroom, Van Herk), PTV calculated by Yukinori method in three directions were (5.89 and 3.95), (5.54 and 3.55), (3.24 and 0.78) mm;Van Herk method were (6.10 and 4.25), (5.73 and 3.83), (3.51 and 1.13) mm;Remeijer method were (6.39 and 4.57), (5.98 and 4.10), (3.69 and 1.33) mm. The volumes of PTV using Yukinori method were significantly smaller (P < 0.05) than Van Herk method and Remeijer method. However, dosimetric indices of PTV (D98, D50, D2) and for OARs (Mean Dose, V20, V5) had no significant difference (P > 0.05) among three methods. Conclusions: In lung SBRT treatment, due to fraction reduction and high level of dose per fraction, ANOVA was able to offset the effect of random factors in systematic errors, reducing the PTV margins and volumes. However, no distinct dose distribution improvement was founded in target volume and organs at risk.展开更多
文摘目的：应用千伏级锥形束CT （kV级CBCT）图像引导放疗技术评估肝癌患者分次放疗间位置的变化。方法15例肝癌患者，每例患者在放疗前行CBCT扫描，每周1～3次，共获取121幅 CBCT图像。离线下以肝脏、椎体外轮廓分别为参照物完成CBCT图像与计划CT的配准，将配准结果定义为分次放疗间肝脏及椎体位置的变化，将两者配准结果的差值定义为肝脏相对于椎体位置的变化，分别予以评估。结果分次放疗间在三维方向，肝脏位移的绝对值以上下方向最大6.3 mm （0～19.3 mm）、左右方向次之2.3 mm（0～16.0 mm）、前后方向最小1.5 mm （0～7.6 mm）（P＜0.001）；椎体位移的绝对值以上下方向最大6.0 mm （0～18.0 mm）、左右方向次之3.0 mm （0～16.0 mm）、前后方向最小2.0 mm （0～10.0 mm）（P＜0.05）；肝脏相对于椎体位移的绝对值以上下方向最大4.8 mm （0.1～19.3 mm）、左右方向次之2.0 mm （0～8.6 mm）、上下方向最小1.4 mm （0～10.3 mm）（P＜0.001）。若通过配准椎体校正患者位置，放疗时左右、上下、前后方向肝脏位移的绝对值可能增大，可能性分别为39.7％、42.1％、43.0％。结论椎体不适于作为肝癌图像引导放疗的参照物。
文摘Objective The aim of this study was to investigate tumor volume changes with kilovoltage cone-beam computed tomography （kV-CBCT） and their dosimetric consequences for non-operative lung cancer during intensity-modulated radiotherapy （IMRT） or fractionated stereotactic radiotherapy. Methods Eighteen patients with non-operative lung cancer who received IMRT consisting of 1.8-2.2 Gy/fraction and five fractions per week or stereotactic radiotherapy with 5-8 Gy/fraction and three fractions a week were studied, kV-CBCT was performed once per week during IMRT and at every fraction during stereotactic radiotherapy. The gross tumor volume （GTV） was contoured on the kV-CBCT images, and adaptive treatment plans were created using merged kV-CBCT and primary planning computed tomogra- phy image sets. Tumor volume changes and dosimetric parameters, including the minimum dose to 95% （D95） or 1% （D1） of the planning target volume （PTV）, mean lung dose （MLD）, and volume of lung tissue that received more than 5 （Vs）, 10 （Vl0）, 20 （V20）, and 30 （V30） Gy were retrospectively analyzed. Results The average maximum change in GTV observed during IMRT or fractionated stereotactic radio- therapy was -25.85% （range, -13.09% --56.76%）. The D95 and Dr of PTV for the adaptive treatment plans in all patients were not significantly different from those for the initial or former adaptive treatment plans. In patients with tumor volume changes of 〉20% in the third or fourth week of treatment during IMRT, adap- tive treatment plans offered clinically meaningful decreases in MLD and V5, V10, V20, and V30; however, in patients with tumor volume changes of 〈 20% in the third or fourth week of treatment as well as in patients with stereotactic radiotherapy, there were no significant or clinically meaningful decreases in the dosimetric parameters. Conclusion Adaptive treatment planning for decreasing tumor volume during IMRT may be beneficial for patients who experience tumor volume changes of 〉20% in the third or fourth week of treatment.
文摘Purpose: To investigate the feasibility of applying ANOVA newly proposed by Yukinori to verify the setup errors, PTV (Planning Target Volume) margins, DVH for lung cancer with SBRT. Methods: 20 patients receiving SBRT to 50 Gy in 5 fractions with a Varian iX linear acceleration were selected. Each patient was scanned with kV-CBCT before the daily treatment to verify the setup position. Two other error calculation methods raised by Van Herk and Remeijer were also compared to discover the statistical difference in systematic errors (Σ), random errors (σ), PTV margins and DVH. Results: Utilizing two PTV margin calculation formulas (Stroom, Van Herk), PTV calculated by Yukinori method in three directions were (5.89 and 3.95), (5.54 and 3.55), (3.24 and 0.78) mm;Van Herk method were (6.10 and 4.25), (5.73 and 3.83), (3.51 and 1.13) mm;Remeijer method were (6.39 and 4.57), (5.98 and 4.10), (3.69 and 1.33) mm. The volumes of PTV using Yukinori method were significantly smaller (P < 0.05) than Van Herk method and Remeijer method. However, dosimetric indices of PTV (D98, D50, D2) and for OARs (Mean Dose, V20, V5) had no significant difference (P > 0.05) among three methods. Conclusions: In lung SBRT treatment, due to fraction reduction and high level of dose per fraction, ANOVA was able to offset the effect of random factors in systematic errors, reducing the PTV margins and volumes. However, no distinct dose distribution improvement was founded in target volume and organs at risk.
