Comparison of variable pressure mattress and thermoplastic mold in cone beam CT-guided radiotherapy of abdominal and pelvic cancer for setup error and effect of body mass index on setup reproducibility
10.19745/j.1003-8868.2025123
- VernacularTitle:CBCT图像引导下负压气垫和热塑体膜在腹盆腔肿瘤放疗中的摆位误差比较及体质量指数对复位通过率的影响
- Author:
Ling-xiao MIAO
1
;
Jin-ye ZHAO
1
;
Heng LI
1
;
Feng-jiao SHAN
1
;
Cui-hong ZHANG
1
Author Information
1. 联勤保障部队第九八○医院放疗科,石家庄 050082
- Publication Type:Journal Article
- Keywords:
abdominal and pelvic cancer;
CBCT image-guided;
variable pressure mattress;
thermoplastic mold;
body mass index;
setup error;
setup repeatability
- From:
Chinese Medical Equipment Journal
2025;46(7):45-50
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore the variable pressure matress and thermoplastic mold applied to cone beam CT-guided radiotherapy of abdominal and pelvic cancer in terms of translation error,rotation angle error and setup reproducibility of patients with different body mass indexes(BMIs),so as to provide references for the selection of body fixation mode.Methods Totally 70 patients with abdominal and pelvic tumors admitted to some hospital from April 2021 to March 2022 were retrospectively selected,and divided into a variable pressure mattress group and a thermoplastic mold group according to the fixation method,with 35 patients in each group.All the patients in the two groups underwent examinations with cone beam computed tomography(CBCT)at the first radiotherapy treatment and during the course of the treatment,and the image registration was carried out between validation images and planning images.The two groups were compared in terms of rotation angle error and thranlation error at the directoins of x axis(lateral directions),y axis(cranial-caudal)and z axis(ventral-dorsal).Taking the center point image of the initial positioning as the reference,the errors of the center points of the two groups at z and y axes(Δz and Δy)were compared.The setup reproducibility was set as Δz≤5 mm and Δy≤3 mm,and the setup reproducibility rates of the two groups were summarized.All the patients were categorized into non-overweight ones(BMI<25 kg/m2)and overweight ones(BMI≥25 kg/m2),and the setup reproducibility rates of the patients with different BMIs were counted.SPSS 26.0 software was used for statistical analysis.Results The two groups had no significant differences in translation error at the directions of x and y axes(P>0.05).The variable pressure mattress group had the translation error at the direction of z axis statistically lower than that of the thermoplastic mold group(P<0.05).There were no significant differences between the two groups in rotation angle error(P=0.219 3).The two groups had significant differences in setup reproducibility(P=0.033 4).The non-overweight patients had the setup reproducibility rate being 40.00%in the variable pressure mattress group,and 77.14%in the thermoplastic mold group;the overweight patients had the setup reproducibility rate being 25.71%in the variable pressure mattress group and only 2.86%in the thermoplastic mold group,with the differences between the two groups being statistically significant(P=0.002 9).Conclusion The variable pressure mattress and thermoplastic mold both result in low setup errors when applied to fixation during the radiotherapy of abdominal and pelvic cancer,the thermoplastic mold fixation can be used for the patients with BMIs lower than 25 kg/m2 with decreased translation errors at the direction of z axis,and the variable pressure mattress fixation was suitable for the patients with BMIs not lower than 25 kg/m2.[Chinese Medical Equipment Journal,2025,46(7):45-50]
