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Objective To compare the dosimetric differences of four fluence smoothing (FS) levels of the Monaco system in intensity-modulated radiation therapy (IMRT) after rectal cancer surgery, and to provide a reference for FS selection in clinical practice. Methods A total of 15 postoperative patients with rectal cancer admitted in 2020 were selected. Under the same optimal conditions, FS was set to Off, Low, Medium, and High for IMRT planning. The data were analyzed by SPSS 20.0 software. The dosimetric parameters of planning target volume and organs at risk (OARs), the number of Segments, the number of monitor units (MUs), the estimated total delivery time (ETDT), and the gamma pass rate were compared between the four FS levels. Results The four FS levels resulted in clinically acceptable dosimetric parameters of the planning target volume and OARs, and there was no significant difference in dose distribution between FS levels. From FS-Off to FS-High, number of Segments, number of Mus, and ETDT decreased by 15.2%, 11.8%, and 6.7%, respectively, whereas gamma pass rate increased by 1.6%. Conclusion The IMRT plans at four FS levels can meet the clinical requirements. Considering the planning quality and execution efficiency, FS-High is recommended for postoperative IMRT of patients with rectal cancer.
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Objective To explore the dosimetric differences of radiotherapy plan for cervical cancer with 4 different fluence smoothing (FS) parameters using Monaco treatment planning system (Monaco TPS). Methods Fifteen patients with ⅠB2 stage cervical cancer in our hospital were enrolled in this study. And a 2 Volumetric Modulated Arc Therapy (VMAT) plan for each patient were completed by Monaco 5.11 TPS according to the X-Ray Voxel Monte Carlo (XVMC) method. For each plan was optimized by FS function, with the level of Off, Low, Medium and High. To compare the difference of plan optimization time, conformity index (CI), Homogeneity index (HI), Dmean, Dmin, D2% of PTV，dose to the organ at risk (OAR)，the number of Segments# and MU#，estimated total delivery time (ETDT), quantum Efficiency (QE) of the plans, the formation of Segments# with the same angle and verification of inserting 729 two-dimensional matrix into PTW octavius 4D module of different FS function levels, with the precondition of the Prescription isodose curve covering 95% of the target area. The data was analysed by multivariate factor analysis with the application of SPSS, and P < 0.05 was considered as statistically significant. And the Planned revenue score of different FS levels was also calculated. Results Except for the Dmin of PTV (the lowest value is (32.09 ± 0.26) Gy for the Off group, and the highest value is (35.98 ± 0.42) Gy for the High group), V40 of the rectum (the lowest value in the Medium group is 55.88% ± 2.02%, and the highest value in the High group was 61.90% ± 2.98%) and bladder (the lowest value was 45.01% ± 2.08% in the Medium group, and the highest value is 50.45% ± 1.98% in the High group), the V20 (the lowest value High group was 49.05% ± 1.98%, the highest value Off group was 56.52% ± 1.75%) of femoral head (P < 0.05), there was no significant difference of the dose assessment results for PTV and OARs in 4 different FS function levels. In the High level, the ETDT, QE and MU# were showed better than other groups evidently, however, the number of Segments# showed no significant difference. The plan validation results was increased with the improvement of FS function level, and the level of High was considered to be the optimal. To compare the score of overall benefits of the plan, the level of Medium (−17.18 ± 0.05) got the highest score, and the Low group (−17.58 ± 0.05) and the High group (−17.42 ± 0.06) have similar scores, and Off group (−18.81 ± 0.08) has the lowest score. Conclusion Different FS levels of the Monaco 5.11 TPS can optimize the radiotherapy plan for cervical cancer, but the level of Medium is considered to be the most applicable.
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Objective To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) plans optimized with 3 different fluence smoothing parameters using Monaco treatment planning system.Methods A total of 15 patients with middle and upper esophageal carcinoma were planned with Low fluence smoothing (Low),Medium fluence smoothing (Medium) and High fluence smoothing (High) during VMAT optimization.The dosimetric differences in D95,D conformity index (CI),homogeneity index (HI) of targets,dose volume histogram (DVH) of organs at risk (OARs),and monitor unit (MU) were compared.Results There were no significant differences in D95,D CI and HI of targets,as well as in V40 and D of the heart,V10,V20 and D of the lung,and segment number among plans optimized with different fluence smoothing techniques (P＞0.05).Plans with high fluence smoothing achieved less V30 of heart,Dmax of cord PRV (t=-2.167,-0.999,P＜0.05),lower MU (t=-3.148,-6.692,P＜O.05),but increased V5 of both lungs (t=1.306,-2.027,P＜O.05)compared with plans with Medium and Low fluence smoothing.Plans with low fluence smoothing irradiated higher dose to the V30 and D to heart (t=O.411,0.589,0.013,P＜0.05),but less V5 of the lungs (t=O.423,P＜0.05) compared with plans with medium fluence smoothing.Conclusions All VMAT plans with 3 different fluence smoothing can meet the clinical requirements.VMAT plans optimized with high fluence smoothing are recommended in the treatment of patients middle and upper thoracic esophageal carcinoma.
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Objective@#To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) plans optimized with 3 different fluence smoothing parameters using Monaco treatment planning system.@*Methods@#A total of 15 patients with middle and upper esophageal carcinoma were planned with Low fluence smoothing (Low), Medium fluence smoothing (Medium) and High fluence smoothing(High) during VMAT optimization. The dosimetric differences in D95, Dmean, conformity index (CI), homogeneity index (HI) of targets, dose volume histogram (DVH) of organs at risk (OARs), and monitor unit (MU) were compared.@*Results@#There were no significant differences in D95, Dmean, CI and HI of targets, as well as in V40 and Dmean of the heart, V10, V20 and Dmean of the lung , and segment number among plans optimized with different fluence smoothing techniques (P>0.05). Plans with high fluence smoothing achieved less V30 of heart, Dmax of cord PRV(t=-2.167, -0.999, P<0.05), lower MU (t=-3.148, -6.692, P<0.05), but increased V5 of both lungs (t=1.306, -2.027, P<0.05) compared with plans with Medium and Low fluence smoothing. Plans with low fluence smoothing irradiated higher dose to the V30 and Dmean to heart (t=0.411, 0.589, 0.013, P<0.05), but less V5 of the lungs (t=0.423, P<0.05) compared with plans with medium fluence smoothing.@*Conclusions@#All VMAT plans with 3 different fluence smoothing can meet the clinical requirements. VMAT plans optimized with high fluence smoothing are recommended in the treatment of patients middle and upper thoracic esophageal carcinoma.