ABSTRACT
Objective:To study the impact of the Varian real-time position management (RPM) respiratory gating system on radiotherapy planning dosimetry.Methods:The radiotherapy plans of 40 cases with thoracic or abdominal tumors were retrospectively selected in this study. The motion phantom for quality control was adopted to generate respiratory gating signals, and the 30%-60% stable phase at the end of expiratory was selected as the respiratory gating window. The dose verification for the abovementioned radiotherapy plans was performed using the Portal Dosimetry (PD) system under RPM respiratory gating mode with the Edge accelerator. Afterwards, dose analysis was performed with different γ passing rate criteria and the distribution characteristics of γ values were analyzed. Finally, the verification results between the non-gating mode and the gating mode were compared.Results:Under the respiratory gating mode, the passing rates of all intensity-modulated radiation therapy/volumetric-modulated arc therapy (IMRT/VMAT) plans with or without flattening filters were over 95.5% by γ criteria of (3%, 3 mm) or (3%, 2 mm) and were over 90% by stricter γ criteria of (2%, 2 mm). All plans met the clinical requirements recommended by the American Association of Physicists in Medicine (AAPM). The passing rates of dose verification under non-gating mode were slightly better than those under respiratory gating mode, and the differences between the two modes were statistically significant (3%/3 mm, Z =-1.45; 3%/2 mm, Z =-2.86; 2%/2 mm, Z =-3.70; 1%/1 mm, Z =-4.52; P<0.05). There was no significant difference in the minimum and maximum values of γ and the share of γ > 1.5 of plan verification result under the two modes. However, the average value and standard deviation of the γ were generally smaller under the non-gating mode. Conclusions:The impact of the introduction of RPM respiratory gating technology on dose is clinically acceptable, and the execution of these plans in this gating mode is safe and reliable.
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Objective:To compare the dosimetric differences between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) on planning target volume (PTV) and organ-at-risk (OAR) for breast cancer after modified radical mastectomy, aiming to provide evidence-based reference for clinical practice.Methods:According to strict inclusion and exclusion criteria, literature search was performed in PubMed, Cochrane Library, FMRS, CNKI, Wanfang Data and VIP full text databases from the inception of databases up to March 2020. The controlled clinical trials of dosimetric comparison between VMAT and IMRT for breast cancer following modified radical mastectomy were selected. The meta-analysis was performed using Stata14 software.Results:The meta-analysis included 281 patients from 13 observational studies. Compared with IMRT, VMAT significantly increased the PTV dose coverage D 95%( P<0.001) and significantly improved the PTV homogeneity index (HI, P<0.001) and conformity index (CI, P=0.004). Compared with IMRT, VMAT more effectively decreased the ipsilateral lung V 20Gy (WMD=1.332, P=0.027) and contralateral lung V 10Gy ( P=0.003). There were no significant differences in theD mean, V 5Gy, V 10Gy and V 30Gy of the ipsilateral lung, D mean and V 5Gy of the contralateral lung, D mean, V 10Gy and V 30Gy of the heart between VMAT and IMRT (all P>0.05). Compared with VMAT, IMRT reduced the cardiac V 5Gy ( P=0.001). However, sensitivity analysis of included literature on cardiac V 5Gy showed that the P value was reversed, indicating that the stability of the results was poor. VMAT significantly shortened the delivery time ( P<0.001) and the number of monitor units ( P<0.001) compared to IMRT. Conclusion:Compared with IMRT, VMAT can achieves superior target dose coverage, HI and CI, better protection for the ipsilateral and contralateral lung, fewer monitor units and shorter delivery time.
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Objective To compare the efficacy and adverse effects of rubomycin plus aracytidine(DA) dripping in bone marrow with DA dripping in vein in the treatment of acute nonlyphocytic leukemia (ANLL). Methods 60 cases of previously untreated ANLL patients were randomly divided into two groups, group A(DA dripping in bone marrow) and group B (DA dripping in vein). the efficacy and adverse effects of both groups were compared. Results The complete remission (CR) rate was 70.0% and 33.3% in group A and group B, and the total response rate was 86.7% and 50.0%, respectively. Both were significant higher than those of group B (P0.05). Conlusions The treating outcome was better in group A than that in group B for ANLL, with higher cure remission rate and lower toxic reaction.
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Biochemical oxygen demand of 5 days (BOD 5) was a very important parameter of monitoring ofwater quality. The classical method presented some shortcomings,such as complexity, long period, requirementof high technology and not promptly reflecting the pollution levels of water body, so it was of no significance fortreatment of industrial waste water. In this paper, two rapid methods for determination of BODs, raising incubation temperature and correlative estimation method, were introduced and their advantages, such as short period and simplicity of operation were verified by experiments. Modification of classical method was of certain instructive significance for the practical application to treatment of industrial waste water and forecast of pollutionlevels of water body.