In this study, we compared the motion accuracy of six degrees of freedom (6D) couch for precision radiotherapy with or without weights attached to the couch. Two digital cameras were focused on the iso-center of a lin...In this study, we compared the motion accuracy of six degrees of freedom (6D) couch for precision radiotherapy with or without weights attached to the couch. Two digital cameras were focused on the iso-center of a linear accelerator. Images of a needle which had been fixed to the 6D couch were obtained using the cameras when the couch moved in translation and rotation around each axis. The three-dimensional (3D) coordinates of the needle were calculated from coordinate values in the images. A coordinate error of the needle position relative to the theoretical position was calculated. The errors were obtained with or without a 60 kg weight attached to the 6D couch, and these errors were compared with each other. The mean distance of the 3D error vectors for the weighted test was 0.21 ± 0.11 mm, and >0.16 ± 0.09 mm for the non-weighted test (p展开更多
Purpose: To study the effect of the Qfix kVue Calypso-compatible couch top on the dosimetry of Spine Stereotactic Body Radiation Therapy (SBRT). Methods and Materials: The computed tomography (CT) data set for Qfix kV...Purpose: To study the effect of the Qfix kVue Calypso-compatible couch top on the dosimetry of Spine Stereotactic Body Radiation Therapy (SBRT). Methods and Materials: The computed tomography (CT) data set for Qfix kVue Calypso-compatible couch top with rails were imported into the treatment planning system (TPS). Nine patients who underwent spine SBRT were selected for this study. The inclusion criteria included patients who were treated on a stereotactic linear accelerator with 5 fractions or less from 2016 to 2017 without the couch model. Seven patients were treated with static intensity-modulated radiation therapy (IMRT) fields and two patients were treated using volumetric modulated arc therapy (VMAT) technique. The dose was recalculated for 1) couch top and rails setup (CR) 2) couch-top no rails setup (CNR), and then compared to 3) no couch no-rails setup (NCNR). Dose to 100% of the target volume (D100%), Dose to cover 99% of the target volume (D99%), Dose to cover 95% of the target volume (D95%), Dose to cover 90% of the target volume (D90%), volume receiving 100% of the prescription dose (V100%), conformity index (CI), dose gradient index (DGI), and spinal cord threshold and maximum dose were compared to the plan with NCNR. Results: The average D100% was 77.89% ± 11.78%, 74.51% ± 12.24%, and 75.83 ± 12.67% for NCNR, CR, CNR (р = 0.84), respectively. The average D99% was 91.64% ± 9.57%, 89.93% ± 9.48%, and 91.15% ± 9.55% for NCNR, CR, CNR (р = 0.98), respectively. The average D95% was 99.14% ± 9.96%, 95.23% ± 9.76, and 96.78% ± 9.84% for NCNR, CR, CNR (р = 0.047), respectively. The average D90% was 101.3% ± 0.65%, 97.11% ± 2.48%, and 98.75% ± 2.12% for NCNR, CR, CNR (р = 0.0004), respectively. The maximum dose to the spinal cord was 1750.79 ± 41.84, 1672.90 ± 40.90, and 1709.91 ± 41.35 (cGy) for NCNR, CR, CNR (р = 0.97), respectively. In all cases, the spinal cord threshold dose was far below the tolerances and the differences were insignificant. Average CI was 1.18 ± 0.16, 0.53 ± 0.39, and 0.86 ± 0.24 for NCNR, CR, CNR (р = 0.0002), respectively. Conclusions: The study investigated the dosimetric impact of Qfix kVue Calypso-compatible couch top on the quality of the spinal SBRT treatment using static IMRT or VMAT techniques. IMRT plans showed more sensitivity to the couch being in the plan than the VMAT plans.展开更多
Objective:To evaluate the accuracy of six-dimensional(6D)treatment couches in minimizing setup errors compared with three-dimensional(3D)treatment couches during radiotherapy for lung cancer patients with brain metast...Objective:To evaluate the accuracy of six-dimensional(6D)treatment couches in minimizing setup errors compared with three-dimensional(3D)treatment couches during radiotherapy for lung cancer patients with brain metastases.Methods:A retrospective analysis was conducted on 40 lung cancer patients with brain metastases who received stereotactic radiotherapy(SRS/SRT)for brain metastases.The cohort was divided into two groups based on the availability of treatment units at the time of planning:20 patients were treated using a 3D couch,and 20 patients with a 6D couch.Daily cone-beam computed tomography(CBCT)registration was used to measure residual setup errors in the x,y,and z axes at two key cranial anatomical landmarks,specifically the internal acoustic meatus(IAM)and crista galli(CG),for both groups.The Shapiro-Wilk test was applied to assess the normality of the data,and the Mann-Whitney U test was performed to determine statistical differences between the two groups,with Bonferroni correction for multiple comparisons.Results:Baseline data indicated that the two groups were well-balanced in terms of gender,age,and distribution of pathological types,number of brain metastases,maximum metastases volume,and relative distance between metastases and isocenter(P>0.05).Setup error data in all directions(IAM_x/y/z,CG_x/y/z)did not follow a normal distribution(P<0.05).The Mann-Whitney U test revealed that setup errors in the 6D group were significantly smaller than those in the 3D group across all directions(IAM_x/y/z,CG_x/y/z,all P<0.001).The mean error reduction exceeded 1 mm in all directions,with the most significant difference observed in the CG_X direction:2.2(1.3,3.3)mm in the 3D group versus 0.3(0.2,0.5)mm in the 6D group,representing a difference of 1.9 mm.Conclusion:The six-dimensional(6D)treatment couch effectively minimizes residual setup errors,especially rotational ones,in radiotherapy for lung cancer patients with brain metastases.展开更多
文摘In this study, we compared the motion accuracy of six degrees of freedom (6D) couch for precision radiotherapy with or without weights attached to the couch. Two digital cameras were focused on the iso-center of a linear accelerator. Images of a needle which had been fixed to the 6D couch were obtained using the cameras when the couch moved in translation and rotation around each axis. The three-dimensional (3D) coordinates of the needle were calculated from coordinate values in the images. A coordinate error of the needle position relative to the theoretical position was calculated. The errors were obtained with or without a 60 kg weight attached to the 6D couch, and these errors were compared with each other. The mean distance of the 3D error vectors for the weighted test was 0.21 ± 0.11 mm, and >0.16 ± 0.09 mm for the non-weighted test (p
文摘Purpose: To study the effect of the Qfix kVue Calypso-compatible couch top on the dosimetry of Spine Stereotactic Body Radiation Therapy (SBRT). Methods and Materials: The computed tomography (CT) data set for Qfix kVue Calypso-compatible couch top with rails were imported into the treatment planning system (TPS). Nine patients who underwent spine SBRT were selected for this study. The inclusion criteria included patients who were treated on a stereotactic linear accelerator with 5 fractions or less from 2016 to 2017 without the couch model. Seven patients were treated with static intensity-modulated radiation therapy (IMRT) fields and two patients were treated using volumetric modulated arc therapy (VMAT) technique. The dose was recalculated for 1) couch top and rails setup (CR) 2) couch-top no rails setup (CNR), and then compared to 3) no couch no-rails setup (NCNR). Dose to 100% of the target volume (D100%), Dose to cover 99% of the target volume (D99%), Dose to cover 95% of the target volume (D95%), Dose to cover 90% of the target volume (D90%), volume receiving 100% of the prescription dose (V100%), conformity index (CI), dose gradient index (DGI), and spinal cord threshold and maximum dose were compared to the plan with NCNR. Results: The average D100% was 77.89% ± 11.78%, 74.51% ± 12.24%, and 75.83 ± 12.67% for NCNR, CR, CNR (р = 0.84), respectively. The average D99% was 91.64% ± 9.57%, 89.93% ± 9.48%, and 91.15% ± 9.55% for NCNR, CR, CNR (р = 0.98), respectively. The average D95% was 99.14% ± 9.96%, 95.23% ± 9.76, and 96.78% ± 9.84% for NCNR, CR, CNR (р = 0.047), respectively. The average D90% was 101.3% ± 0.65%, 97.11% ± 2.48%, and 98.75% ± 2.12% for NCNR, CR, CNR (р = 0.0004), respectively. The maximum dose to the spinal cord was 1750.79 ± 41.84, 1672.90 ± 40.90, and 1709.91 ± 41.35 (cGy) for NCNR, CR, CNR (р = 0.97), respectively. In all cases, the spinal cord threshold dose was far below the tolerances and the differences were insignificant. Average CI was 1.18 ± 0.16, 0.53 ± 0.39, and 0.86 ± 0.24 for NCNR, CR, CNR (р = 0.0002), respectively. Conclusions: The study investigated the dosimetric impact of Qfix kVue Calypso-compatible couch top on the quality of the spinal SBRT treatment using static IMRT or VMAT techniques. IMRT plans showed more sensitivity to the couch being in the plan than the VMAT plans.
文摘Objective:To evaluate the accuracy of six-dimensional(6D)treatment couches in minimizing setup errors compared with three-dimensional(3D)treatment couches during radiotherapy for lung cancer patients with brain metastases.Methods:A retrospective analysis was conducted on 40 lung cancer patients with brain metastases who received stereotactic radiotherapy(SRS/SRT)for brain metastases.The cohort was divided into two groups based on the availability of treatment units at the time of planning:20 patients were treated using a 3D couch,and 20 patients with a 6D couch.Daily cone-beam computed tomography(CBCT)registration was used to measure residual setup errors in the x,y,and z axes at two key cranial anatomical landmarks,specifically the internal acoustic meatus(IAM)and crista galli(CG),for both groups.The Shapiro-Wilk test was applied to assess the normality of the data,and the Mann-Whitney U test was performed to determine statistical differences between the two groups,with Bonferroni correction for multiple comparisons.Results:Baseline data indicated that the two groups were well-balanced in terms of gender,age,and distribution of pathological types,number of brain metastases,maximum metastases volume,and relative distance between metastases and isocenter(P>0.05).Setup error data in all directions(IAM_x/y/z,CG_x/y/z)did not follow a normal distribution(P<0.05).The Mann-Whitney U test revealed that setup errors in the 6D group were significantly smaller than those in the 3D group across all directions(IAM_x/y/z,CG_x/y/z,all P<0.001).The mean error reduction exceeded 1 mm in all directions,with the most significant difference observed in the CG_X direction:2.2(1.3,3.3)mm in the 3D group versus 0.3(0.2,0.5)mm in the 6D group,representing a difference of 1.9 mm.Conclusion:The six-dimensional(6D)treatment couch effectively minimizes residual setup errors,especially rotational ones,in radiotherapy for lung cancer patients with brain metastases.
