Purpose:

With the widespread prevalence of Corona Virus Disease 2019 (COVID-19), cancer patients are suggested to wear a surgical mask during radiation treatment. In this study, cone beam CT (CBCT) was used to investigate the effect of surgical mask on setup errors in head and neck radiotherapy.

Methods:

A total of 91 patients with head and neck tumors were selected. CBCT was performed to localize target volume after patient set up. The images obtained by CBCT before treatment were automatically registered with CT images and manually fine-tuned. The setup errors of patients in 6 directions of Vrt, Lng, Lat, Pitch, Roll and Rotation were recorded. The patients were divided into groups according to whether they wore the surgical mask, the type of immobilization mask used and the location of the isocenter. The setup errors of patients were calculated. A t-test was performed to detect whether it was statistically significant.

Results:

In the 4 groups, the standard deviation in the directions of Lng and Pitch of the with surgical mask group were all higher than that in the without surgical mask group. In the head-neck-shoulder mask group, the mean in the Lng direction of the with surgical mask group was larger than that of the without surgical mask group. In the lateral isocenter group, the mean in the Lng and Pitch directions of the with surgical mask group were larger than that of the without surgical mask group. The t-test results showed that there was significant difference in the setup error between the 2 groups (p = 0.043 and p = 0.013, respectively) only in the Lng and Pitch directions of the head-neck-shoulder mask group. In addition, the setup error of 6 patients with immobilization open masks exhibited no distinguished difference from that of the patients with regular immobilization masks.

Conclusion:

In the head and neck radiotherapy patients, the setup error was affected by wearing surgical mask. It is recommended that the immobilization open mask should be used when the patient cannot finish the whole treatment with a surgical mask.

中文翻译：

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手术口罩对头颈部放射治疗中安装错误的影响

目的：

随着2019年冠状病毒病（COVID-19）的广泛流行，建议癌症患者在放射治疗期间戴上外科口罩。在这项研究中，锥束CT（CBCT）用于研究手术口罩对头颈部放射治疗中设置错误的影响。

方法：

总共选择了91例头颈部肿瘤患者。设置患者后进行CBCT以定位目标体积。在治疗前通过CBCT获得的图像会自动与CT图像对齐，并进行手动微调。记录患者在Vrt，Lng，Lat，Pitch，Roll和Rotation六个方向上的设置误差。根据患者是否佩戴手术口罩，使用的固定口罩的类型以及等中心点的位置将患者分为几组。计算患者的设置误差。进行t检验以检测其是否具有统计学意义。

结果：

在4组中，有手术口罩组的Lng和Pitch方向的标准偏差均高于无手术口罩组的Lng和Pitch方向。在头颈肩面具组中，有手术口罩组的Lng方向的平均值大于无手术口罩组的Lng方向的平均值。在等距外侧组中，有手术口罩组的Lng和Pitch方向的平均值大于无手术口罩组的Lng和Pitch方向的平均值。所述吨-test结果表明，在2个组之间在设置误差显著差异（p = 0.043和p=分别为0.013）仅在头颈肩面具组的Lng和Pitch方向上。此外，6例固定式开放口罩患者的设置误差与常规固定式口罩患者无明显差异。

结论：

在头颈部放疗患者中，设置错误受戴口罩的影响。当患者无法用手术口罩完成全部治疗时，建议使用固定式开放式口罩。