基于磁共振放疗平台模拟胰腺癌不同配准策略的研究OACSTPCD

Objective:To investigate the differences among bone alignment,skin surface alignment and tumor alignment for adaptive radiotherapy of pancreatic cancer with a magnetic resonance accelerator,and provide evidence for precision ra-diotherapy alignment strategies for pancreatic cancer.Methods:From November 2021 to April 2023,16 patients with pancreatic cancer treated with a Unity magnetic resonance accelerator at Sichuan Cancer Hospital were selected.MR im-ages were obtained before each radiotherapy session,and were registered with planned CT images.Alignment was performed in three ways,bone,patient's body surface,and actual tumor.Setup errors in the left-right(X axis),superior-inferior(Y axis)and anterior-posterior(Z axis)directions were obtained.The differences between the two alignment methods and the tumor alignment were compared.The results were expressed in ab-solute values,and the statistical difference between the two groups and the tumor alignment was calculated.The frequency of displacement values was counted to verify the clinical stability.Results:A total of 92 radiotherapy sessions were performed in 16 patients.The differences in the X,Y and Z directions in the bone alignment group were(1.12±0.90)mm,(2.01±2.12)mm and(0.10±0.84)mm,the differences in the X,Y and Z directions were(1.64±1.28)mm,(3.48±2.29)mm and(3.94±2.76)mm in the skin surface alignment group.Differences between tumor alignment and skin surface a-lignment were statistically significant in X and Z axes.The frequency of error greater than 5 mm in the Y-axis direction in the bone alignment strategy was 14.13％,while the skin surface alignment strategy had errors greater than 5 mm of different fre-quency in the X,Y and Z directions(1％in the X direction,16.3％in the Y direction and 29.35％in the Z direction).Conclusion:Bone alignment is more reliable in image-guided radiotherapy for pancreatic cancer.However,it is shown that there are substantial differences in the superior-inferior direction.Therefore,individual treatment strategies should be consid-ered for radiotherapy in pancreatic cancer.