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Objective:To study and analyze the uncertainty of active breathing coordinator (ABC) technology for liver and lung cancer therapy using proton and heavy ion.Methods:Before each treatment, each patient received a verification radiograph through the supporting imaging frame in treatment room. 200 verification radiographs were taken for 20 lung cancer patients and 200 for 20 liver cancer patients. Ipiodol markers, which were fixed relative to the location of the tumor, were injected into the liver cancer patients. The position changes of ipiodol markers could reflect the position changes of liver tumors. Verification radiographs were registered with the vertebral body as the main target, and the change value of tumor location was recorded.Results:For liver cancer cases, the values of position change in the left and right, head and foot, and dorsal abdomendirection were (-0.05± 0.28) cm, (0.15±0.33) cm, (-0.12±0.27) cm, and (-0.03±0.13) cm, (-0.05±0.14) cm and (0.02±0.16) cmfor lung cancer cases, respectively ( P=0.280, <0.001, <0.001). For liver cancer cases, the dispersionin the left and right, head and foot, and dorsal abdomendirectionwas (0.20±0.09) cm, (0.25±0.06) cm, (0.19±0.09) cm, and (0.09±0.03) cm, (0.10±0.03) cm and (0.13±0.03) cm for lung cancer cases, respectively ( P<0.001, <0.001, 0.008). The proportion of tumor location changes of≤5 mm in three directions in liver and lung cancer patientswas (92%, 83%, 93%) vs. (99%, 99%, 100%)( P=0.030, 0.002, 0.007). Conclusion:The application of ABC technology in the proton heavy ion therapy of lung and liver cancer has good reproducibility, and the stability of ABC technology in the treatment of lung cancer is better than that of liver cancer.
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Objective:To compare the difference between active breathing coordinator (ABC) technique and free breathing (FB) mode combined with bodyfix stereotactic radiotherapy (SBRT) for chest tumors.Methods:40 thoracic tumor patients receiving SBRT were randomly selected and divided into the ABC technique group and FB model group. After fixation with bodyfix fixing devices in two groups, cone-beam CT (CBCT) scan images before each SBRT were matched with the plan reference images. The setup errors in the left-right (LR), superior-inferior (SI) and anterior-post (AP) directions were obtained. Then, the setup errors were corrected. SBRT was performed and split intra-fraction CBCT was conducted simultaneously, which was repeated until the end of treatment.Results:In the ABC technique group, the setup errors in the LR, SI and AP directions were (0.25±0.21) cm, (0.28±0.21) cm, and (0.21±0.24) cm, significantly less compared with (0.31±0.22) cm, (0.32±0.21) cm and (0.37±0.23) cm in the FB model group (all P<0.05). The V 30Gy of the heart, the V 20Gy and V 30Gy of the lung in the ABC technique group were significantly less than those in the FB model group (0.31%∶7.35%; 24.5%∶32.9%; 19.5%∶25.8%, all P<0.05). Conclusions:ABC technique combined with bodyfix fixation device may be superior to FB mode in SBRT for chest tumors, which remains to be validated by subsequent studies with large samples.
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Objective To compare and analyze the dosimetric characteristics of the intensity-modulated arc therapy (RapidArc) combined with active breathing coordinator (ABC) in the thoracic esophageal carcinoma radiation therapy. Methods Ten thoracic esophageal carcinoma patients undergoing radiotherapy were selected for this study.The CT simulations were performed under three breath patterns respectively:moderate deep inspiration breath-hold (mDIBH) with ABC aid; Set the trigger threshold to 80％ of the peak of the respiration curve; and free breathing (FB).Based on the corresponding CT image sets,three treatment plans were generated for each patient respectively:Arc-ABC( three small arcs),ArcFB (consisted of two coplanar full arcs) and IMRT-FB plan.The following dosimetric parameters were compared among different plans:D2％,D98％,V95,homogeneity index ( HI),conformal index ( CI ) the percentage of volume receiving dose of over x Gy (Vx),monitor unit (MU),control points and treatment time.Results The planning target volume ( PTV ) of FB was 376 cm3 which decreased to 260 cm3 after using ABC.For mDIBH and FB patients,the total lung volumes were 5964.6 cm3(35％ more than FB) and 3838.8 cm3 respectively; the heart volumes were 524.4 cm3 and 642.7 cm3 respectively. No significant difference was observed among Arc-ABC,IMRT-FB and Arc-FB in terms of D2,D98,V95,CI and HI.For Arc-ABC plans,there were significant decreases of radiation dose in total-lung's V10,V20,V30,V40 and mean lung dose ( F =4.38,5.34,4.07,3.89,4.28,P ＜0.05).Various dose decreases of heart V20,V3,V40,Dmean and spinal cord Dmax were observed,yet no statistically significant difference existed.The MUs and total control points of Arc-ABC plans were significantly lower than other plans ( F =26.86,12.56,P ＜ 0.05 ).Conclusions When thoracic esophageal carcinoma patients were treated with radiotherapy,the combined utilization of RapidArc and ABC can potentially decrease the volume of irradiated lung yet escalate the dose in target.