A dosimetric comparison of static intensity-modulated radiotherapy, volumetric-modulated arc therapy,and helical tomotherapy after surgery for gastroesophageal junction adenocarcinoma / 中华放射肿瘤学杂志

ABSTRACT

Objective To investigate the effects of different irradiation techniques on dose distribution in target volume and normal tissues after the radical surgery for gastroesophageal junction adenocarcinoma,and to provide the optimal regimen for clinical treatment.Methods A total of 9 patients with gastroesophageal junction adenocarcinoma who underwent radical esophagus-proximal gastrectomy or total gastrectomy were enrolled.The therapeutic regimens of five-field static intensity-modulated radiotherapy (IMRT),volumetric-modulated arc therapy (VMAT),and helical tomotherapy (HT) were designed for each patient,and the dose-volume histogram was used to evaluate the effects of different irradiation techniques on the conformity index (CI) and homogeneity index (HI) of target volume and the surrounding normal tissues. The prescribed dose was 45 Gy at 1.8 Gy/fraction.The patients received oral S-1 as concurrent chemotherapy at a dose of 80 mg/(m 2? d) twice a day during radiotherapy.Results Compared with IMRT and VMAT,HT had better CI and HI of the target volume,as well as a better protective effect on the intestinal tract and bone marrow.Compared with IMRT and HT,VMAT had a lower V20 and V30 for the left kidney and a lower V30 for the heart,while IMRT had lower V5 and V10 for both lungs;V20 and mean dose showed no significant differences between the three techniques.HT had the highest mean sub-field hop count,followed by IMRT and VMAT.Conclusions IMRT, VMAT, and HT can meet the clinical requirements,but besides ensuring the best CI and HI of the target volume,HT has a good protective effect on the intestine and spinal cord and can help to reduce the incidence of adverse events in patients.