Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is im...Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is important to prevent adverse events in normal tissues. In the present study, we evaluated the impact of variation in bladder volume on the doses to various organs. A total of 35 patients underwent definitive radiotherapy at Saitama Medical Center. A Light Speed RT16 (GE Healthcare) was used for planning and to obtain examination CT images. Such images were acquired after 4 - 6 days of planning CT image acquisition. The IMRT plans were optimized using the planning CT data to satisfy the dose constraints set by our in-house protocols for the PTV and the OARs. The dose distributions were then re-calculated using the same IMRT beams, and checked on examination CT images. It was clear that bladder volume affected the doses to certain organs. We focused on the prostate, bladder, rectum, small bowel, and large bowel. Regression coefficients were calculated for variables that correlated strongly with bladder volume (p < 0.05). We found that variation in bladder volume [cm<sup>3</sup>] predicted deviations in the bladder V<sub>70Gy</sub>, V<sub>50Gy</sub>, and V<sub>30Gy</sub> [%];the maximum dose to the small bowel [cGy];and the maximum dose to the large bowel [cGy]. The regression coefficients were -0.065, -0.125, -0.180, -10.22, and -9.831, respectively. We evaluated the impacts of such variation on organ doses. These may be helpful when checking a patient’s bladder volume before daily IMRT for localized prostate cancer.展开更多
<strong>Purpose:</strong><span style="font-family:""><span style="font-family:Verdana;"> The study was performed comparing dosimetric characteristics of volumetric modu...<strong>Purpose:</strong><span style="font-family:""><span style="font-family:Verdana;"> The study was performed comparing dosimetric characteristics of volumetric modulated arc therapy (VMAT) and field-in-field (FiF) techniques on a patient with synchronous bilateral breast carcinoma. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> The patients with bilateral breast cancer treatment were included in this study. A total dose of 40.05 Gy in 15 fractions was prescribed to the Planning Target Volume (PTV) of the whole bilateral breast cancer with the supraclavicular and infraclavicular nodes, with a complementary boost of 10 Gy in 4 fractions to the surgical bed (PTV</span><sub><span style="font-family:Verdana;">boost</span></sub><span style="font-family:Verdana;">). For both radiotherapy techniques, several V</span><sub><span style="font-family:Verdana;">xGy</span></sub><span style="font-family:Verdana;"> parameters were analyzed for the PTVs, together with the Conformity index (CI), the Homogeneity index (HI) and the critical organs at risk (OARs), lungs and heart. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> The patient was treated by the VMAT technique and the daily treatment time was less than 20 minutes with daily CBCT imaging. In the VMAT plan, the PTV 95% dose covered 38.89 ± 0.81 Gy, compared to 37.26 ± 1.02 Gy in the FiF technique. The VMAT plan improved the dose homogeneity index and lower dose in lung towards high dose region. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> The study demonstrates the viability of the VMAT technique in the treatment of bilateral breast cancer. The introduced single isocentric VMAT technique is fast to deliver and it increases the dose homogeneity of the target volume with some limitations. The treatment was well tolerated, without interruption of the treatment courses caused by treatment</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">related toxicities.</span>展开更多
目的本文通过拟合调强放射治疗中危及器官(organ at risk,OAR)剂量公式,探究危及器官剂量的评估方法,从而相对精准地保障调强放疗计划的质量。方法选取2017年1月至2018年12月于西南医科大学附属医院肿瘤科接受调强放疗的乳腺癌保乳术后...目的本文通过拟合调强放射治疗中危及器官(organ at risk,OAR)剂量公式,探究危及器官剂量的评估方法,从而相对精准地保障调强放疗计划的质量。方法选取2017年1月至2018年12月于西南医科大学附属医院肿瘤科接受调强放疗的乳腺癌保乳术后病人(n=19)与鼻咽癌病人(n=55)的放疗计划,将OAR分割为多个子器官,子器官归一化后得到平均剂量均值,然后与各子器官到靶区表面最短距离轨迹图进行数据拟合得到相应拟合公式。结果显示不同OAR各子器官的归一化平均剂量均值与其到靶区表面最短距离呈负相关性;对上述因素进行拟合得出相应拟合公式,并评价该拟合公式取得了较好的拟合结果。结论本研究提出了一种较简便的调强放疗计划OAR剂量评估的方法,从而减少人为主观因素对OAR剂量的影响,提高调强放疗计划质量。展开更多
目的分析比较3种不同射野方法在宫颈癌术后放射治疗中的剂量学情况。方法选择30例宫颈癌术后放射治疗患者,年龄37~68岁,中位年龄54岁。对所有病例进行3种不同射野方法计划设计,分别为5野调强放射治疗(5FIMRT)、7野调强放射治疗(7FIMRT)...目的分析比较3种不同射野方法在宫颈癌术后放射治疗中的剂量学情况。方法选择30例宫颈癌术后放射治疗患者,年龄37~68岁,中位年龄54岁。对所有病例进行3种不同射野方法计划设计,分别为5野调强放射治疗(5FIMRT)、7野调强放射治疗(7FIMRT)、单弧容积旋转调强放射治疗(VMAT),处方剂量均设计为45 Gy/25 F。对比3组治疗计划的靶区剂量、适形度指数(CI)、均匀性指数(HI),以及危及器官的受照剂量、机器跳数和治疗时间等。结果靶区CI:VMAT优于7FIMRT(0.879±0.027 vs 0.859±0.032;t=5.759,P<0.05),而7FIMRT优于5FIMRT(0.859±0.032vs 0.835±0.033;t=4.739,P<0.05);靶区HI:VMAT与7FIMRT相当(0.119±0.019 vs 0.119±0.016;t=0.045,P=0.954),却优于5FIMRT(0.119±0.019 vs 0.123±0.017;t=6.587,P<0.05);但VMAT靶区内平均剂量[(47.73±0.56)Gy]略高于5FIMRT[(47.55±0.47)Gy]、7FIMRT[(47.51±0.43)Gy](t=6.753、8.613,P<0.05);在危及器官的保护上,VMAT计划的直肠和膀胱受照剂量尤其在高剂量区域(V_(30)、V_(40))比IMRT有所减少,股骨头受照剂量整体(V_(20)、V_(30)、V_(40))都有下降,脊髓最大剂量(D2%)明显下降,其他参数差异无统计学意义(P>0.05)。VMAT相比于5FIMRT、7FIMRT治疗时间缩短一半以上[VMAT:(3.38±0.20)min;5FIMRT:(6.22±0.31)min;7FIMRT:(8.11±0.23)min。t=7.231、9.478,P<0.05],机器跳数也有减少(VMAT:574±75;5FIMRT:606±74;7FIMRT:666±88。t=2.783、3.424,P<0.05)。结论需要接受放射治疗的宫颈癌患者,IMRT与VMAT两种技术均可达到靶区剂量要求。在机器条件及经济条件允许的前提下,推荐使用VMAT;它在治疗时间、治疗精度和危及器官的保护等方面优于IMRT,具有一定的临床优势。展开更多
文摘Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is important to prevent adverse events in normal tissues. In the present study, we evaluated the impact of variation in bladder volume on the doses to various organs. A total of 35 patients underwent definitive radiotherapy at Saitama Medical Center. A Light Speed RT16 (GE Healthcare) was used for planning and to obtain examination CT images. Such images were acquired after 4 - 6 days of planning CT image acquisition. The IMRT plans were optimized using the planning CT data to satisfy the dose constraints set by our in-house protocols for the PTV and the OARs. The dose distributions were then re-calculated using the same IMRT beams, and checked on examination CT images. It was clear that bladder volume affected the doses to certain organs. We focused on the prostate, bladder, rectum, small bowel, and large bowel. Regression coefficients were calculated for variables that correlated strongly with bladder volume (p < 0.05). We found that variation in bladder volume [cm<sup>3</sup>] predicted deviations in the bladder V<sub>70Gy</sub>, V<sub>50Gy</sub>, and V<sub>30Gy</sub> [%];the maximum dose to the small bowel [cGy];and the maximum dose to the large bowel [cGy]. The regression coefficients were -0.065, -0.125, -0.180, -10.22, and -9.831, respectively. We evaluated the impacts of such variation on organ doses. These may be helpful when checking a patient’s bladder volume before daily IMRT for localized prostate cancer.
文摘<strong>Purpose:</strong><span style="font-family:""><span style="font-family:Verdana;"> The study was performed comparing dosimetric characteristics of volumetric modulated arc therapy (VMAT) and field-in-field (FiF) techniques on a patient with synchronous bilateral breast carcinoma. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> The patients with bilateral breast cancer treatment were included in this study. A total dose of 40.05 Gy in 15 fractions was prescribed to the Planning Target Volume (PTV) of the whole bilateral breast cancer with the supraclavicular and infraclavicular nodes, with a complementary boost of 10 Gy in 4 fractions to the surgical bed (PTV</span><sub><span style="font-family:Verdana;">boost</span></sub><span style="font-family:Verdana;">). For both radiotherapy techniques, several V</span><sub><span style="font-family:Verdana;">xGy</span></sub><span style="font-family:Verdana;"> parameters were analyzed for the PTVs, together with the Conformity index (CI), the Homogeneity index (HI) and the critical organs at risk (OARs), lungs and heart. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> The patient was treated by the VMAT technique and the daily treatment time was less than 20 minutes with daily CBCT imaging. In the VMAT plan, the PTV 95% dose covered 38.89 ± 0.81 Gy, compared to 37.26 ± 1.02 Gy in the FiF technique. The VMAT plan improved the dose homogeneity index and lower dose in lung towards high dose region. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> The study demonstrates the viability of the VMAT technique in the treatment of bilateral breast cancer. The introduced single isocentric VMAT technique is fast to deliver and it increases the dose homogeneity of the target volume with some limitations. The treatment was well tolerated, without interruption of the treatment courses caused by treatment</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">related toxicities.</span>
文摘目的本文通过拟合调强放射治疗中危及器官(organ at risk,OAR)剂量公式,探究危及器官剂量的评估方法,从而相对精准地保障调强放疗计划的质量。方法选取2017年1月至2018年12月于西南医科大学附属医院肿瘤科接受调强放疗的乳腺癌保乳术后病人(n=19)与鼻咽癌病人(n=55)的放疗计划,将OAR分割为多个子器官,子器官归一化后得到平均剂量均值,然后与各子器官到靶区表面最短距离轨迹图进行数据拟合得到相应拟合公式。结果显示不同OAR各子器官的归一化平均剂量均值与其到靶区表面最短距离呈负相关性;对上述因素进行拟合得出相应拟合公式,并评价该拟合公式取得了较好的拟合结果。结论本研究提出了一种较简便的调强放疗计划OAR剂量评估的方法,从而减少人为主观因素对OAR剂量的影响,提高调强放疗计划质量。
文摘目的分析比较3种不同射野方法在宫颈癌术后放射治疗中的剂量学情况。方法选择30例宫颈癌术后放射治疗患者,年龄37~68岁,中位年龄54岁。对所有病例进行3种不同射野方法计划设计,分别为5野调强放射治疗(5FIMRT)、7野调强放射治疗(7FIMRT)、单弧容积旋转调强放射治疗(VMAT),处方剂量均设计为45 Gy/25 F。对比3组治疗计划的靶区剂量、适形度指数(CI)、均匀性指数(HI),以及危及器官的受照剂量、机器跳数和治疗时间等。结果靶区CI:VMAT优于7FIMRT(0.879±0.027 vs 0.859±0.032;t=5.759,P<0.05),而7FIMRT优于5FIMRT(0.859±0.032vs 0.835±0.033;t=4.739,P<0.05);靶区HI:VMAT与7FIMRT相当(0.119±0.019 vs 0.119±0.016;t=0.045,P=0.954),却优于5FIMRT(0.119±0.019 vs 0.123±0.017;t=6.587,P<0.05);但VMAT靶区内平均剂量[(47.73±0.56)Gy]略高于5FIMRT[(47.55±0.47)Gy]、7FIMRT[(47.51±0.43)Gy](t=6.753、8.613,P<0.05);在危及器官的保护上,VMAT计划的直肠和膀胱受照剂量尤其在高剂量区域(V_(30)、V_(40))比IMRT有所减少,股骨头受照剂量整体(V_(20)、V_(30)、V_(40))都有下降,脊髓最大剂量(D2%)明显下降,其他参数差异无统计学意义(P>0.05)。VMAT相比于5FIMRT、7FIMRT治疗时间缩短一半以上[VMAT:(3.38±0.20)min;5FIMRT:(6.22±0.31)min;7FIMRT:(8.11±0.23)min。t=7.231、9.478,P<0.05],机器跳数也有减少(VMAT:574±75;5FIMRT:606±74;7FIMRT:666±88。t=2.783、3.424,P<0.05)。结论需要接受放射治疗的宫颈癌患者,IMRT与VMAT两种技术均可达到靶区剂量要求。在机器条件及经济条件允许的前提下,推荐使用VMAT;它在治疗时间、治疗精度和危及器官的保护等方面优于IMRT,具有一定的临床优势。
