The Impact of 4DCT Combined With Respiratory Management on the Accuracy of SBRT in NSCLC
Objective By comparing the parameters of stereotactic body radiotherapy(SBRT)planning under four dimension computed tomography(4DCT)combined with respiratory gating,abdominal compression,and free breathing modes,the impact of respiratory management on the volume and dose accuracy of the tumor(NSCLC)target area is analyzed.Methods A total of 12 patients with non-small cell lung cancer who received stereotactic radiotherapy at Central Hospital Affiliated to Shandong First Medical University from October 2021 to December 2022 were selected,three sets of image plans were designed,and each set of 12 cases as a group.The 4DCT scans were collected,the CT data were reconstructed according to the respiratory time-phase,and the 0%to 90%images(0%at the end of inspiration and 50%at the end of expiration)were obtained by layered processing.The tumor target area was outlined in each time-phase,and the full-time images were fused into full-time images by using the maximum density projection to simulate the normal CT images in the free-breathing mode(FB'group);30%to 70%time-phase images were fused by using the maximum density projection,which were defined as abdominal moderate pressure group images(RA'group),because the time-phase was the same as that of abdominal compression by using the breathing attachment.The 0%time-phase image at the end of inspiration was modeled as the active breathing control state image(ABC'group).Tumor target areas,intra-tumor target areas,and planned target areas were obtained on these three groups of images,and the dosimetric differences in tumor target areas and organs in crisis were compared among the three treatment modalities.Results(1)There was a significant difference in the volume of the target area within the tumor between groups ABC',RA'and FB'(P<0.05).The conformal index,uniformity index,dose of 5%PTV volume,and dose of 95%PTV volume of the planned target area were not statistically significant(P>0.05).(2)The percentage volume of dual lung dose 5 Gy and 20 Gy,and average lung dose were statistically significant(P<0.05).Maximum cardiac dose,less than 15 cm 3 The volume dose showed that the RA'group and ABC'group were slightly lower than the FB'group,but there was no statistical significance(P>0.05).Conclusion The application of respiratory gating,moderate abdominal pressure,and other respiratory management methods combined with four-dimensional CT scanning in stereotactic radiotherapy for non-small cell lung cancer effectively reduces the target area volume,percentage volume of dual lung dose 5 Gy and 20 Gy,average lung dose,and other indicators compared to the FB'group under free breathing mode,reducing the impact of respiratory activity on the target area,and improving the accuracy of localization and treatment.Abdominal pressure breathing management technology is an effective remedial measure for those who are not suitable for respiratory gated breathing management technology.
four dimension computed tomographycombined with respiratory managementnon-small cell lung cancerstereotactic body radiotherapytreatment planningprecision impact
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