Comparative clinical dosimetry study of domestic versus imported precision radiotherapy equipment in postoperative radiotherapy of rectal cancer

  Background  Radiotherapy is one of the main treatment methods for rectal cancer. There are many types of radiotherapy equipment in China, with different levels. The radiotherapy equipments in grassroots hospitals are backward, and most of them are mainly domestic radiotherapy equipment.

  Objective  To investigate the clinical dosimetry characteristics and treatment efficiency of domestic and imported precision radiotherapy equipment in postoperative radiotherapy for rectal cancer, so as to provide evidence for clinical application.

  Methods  Ten patients with postoperative adjuvant radiotherapy for rectal cancer from July to October in 2017 were selected from the Radiotherapy Department of the First Medical Center of Chinese PLA General Hospital, the radiotherapy plan was designed and verified by domestic accelerator (group A) and imported accelerator (group B), and the results were compared. Dose statistics were performed on the target volume and organs at risk through the dose volume histogram, and the target volume conformity index (CI) and homogeneity index (HI) were calculated according to the corresponding formula, and finally the machine treatment time and the number of hops were counted. Statistical analysis was performed using paired t-test.

  Results  The treatment plans of both domestic and imported precision radiotherapy equipment could meet the requirements of the prescribed dose in the target area and the limit of organs at risk. There was no statistical difference in D_95% of PTV between the two groups, but the D_2%, D_5%, D_98%, CI and HI of PTV in group B were better than those in group A (P<0.05). In the protection of normal organs, there was no significant difference in the V₃₀ of the small intestine and the V₄₀ of the bilateral femoral head between the two groups, while the V₄₀ of the bladder in group A was better than that in group B (P<0.05). There was no statistical difference in the pass rate of the plan between the two groups, while the efficiency of plan implementation in group A was slightly better than that in group B (P<0.05).

  Conclusion  Both domestic and imported precision radiotherapy equipment can meet the target dose distribution requirements of IMRT after rectal cancer surgery, and it is safe and feasible dosimetrically. Hospitals at all levels can choose and apply them according to clinical needs.