The relationship of target area and lung volume ratio with prescription dose of IMRT for esophageal cancer / 中国辐射卫生

ABSTRACT

Objective To study the relationship between the ratio of target volume to lung volume and the prescription dose in intensity modulated radiation therapy (IMRT) for esophageal cancer, so as to help clinicians to choose the appropriate prescription dose according to the target situation. Methods 80 patients with esophageal cancer were randomly selected. The lesion range included all types of esophageal cancer, and the target area was outlined according to ICRU (International Commission Radiological Units) 50 and ICRU62. Set statistical parameters and plan objectives. Statistical analysis was performed according to the statistical results of the parameters. The critical value of volume ratio is obtained by fitting calculation. Results there was a positive linear correlation between volume ratio and lung V5, V20, V30 and average lung dose. The critical value of volume ratio is 10% for 60 Gy and 13% for 50 Gy. Conclusion according to the research results, it can be predicted that when the ratio of target volume to lung volume is more than 10%, the prescribed dose should not be higher than 60 Gy; when the ratio of target volume to lung volume is more than 13%, the prescribed dose should be selected cautiously, meanwhile in the condition of whose target volume exceeds lung segment the prescribed dose. This provides a reference for clinicians when choose the prescription dose and target range while making the target delineation.