Evaluation of registration accuracy of MIM system using liver biomechanical deformation model
10.19745/j.1003-8868.2025028
- VernacularTitle:基于肝脏生物力学形变模型的MIM系统配准精度评估
- Author:
Xiao-fang GOU
1
;
Xiu-xia FENG
;
Song FAN
Author Information
1. 四川大学华西医院肿瘤放射治疗科,成都 610041
- Publication Type:Journal Article
- Keywords:
MIM system;
biomechanical deformation model;
deformable image registration;
registration accuracy;
adaptive radiotherapy
- From:
Chinese Medical Equipment Journal
2025;46(2):49-55
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the registration accuracy of progressive biomechanical shrinkage set of MIM system to provide registration evaluation data support for registration demand scenarios such as treatment response feedback and dose stacking in tumor adaptive radiotherapy.Methods The CT images of a fresh pork liver with 60 gold markers in different shrinkage states at different heating time were used as the phantom images containing gold markers,and the phantom images without gold markers were obtained by replacing the pixel values at the high-density points containing the gold markers with the pixel averages of the pork liver tissue near the gold marker points.Secondly,the two types of phantom images were introduced into MIM system for registration by two methods of deformable image registration(DIR)and contour boundary-based hybrid deformable image registration(HY-DIR).Finally,the mean values of target registration errors(TRE)were cal-culated between the real gold marker points and the ones by registrating respectively all the gold marker points,23 internal points and 37 superfacial points.The Dice coefficients and Hausdorff distances were computed,and correlation and difference analyses were carried out between four groups of DIR with gold marker,HY-DIR with gold marker,DIR without gold marker and HY-DIR without gold marker.SPSS 25.0 software was used for statistical analysis.Results At 30 s time-phase,the mean values of TRE ranged from 2.14 to 2.20 mm,and the Dice coefficients were all 0.94;at 60-90 s time-phase,the mean values of TRE were from 3.02 to 5.32 mm,and the Dice coefficients were restricted between 0.95 and 0.97;at 110-200 s time-phase,the mean values of TRE were higher than 4 mm,and the Dice coefficients were from 0.93 to 0.96.The Hausdorff distance had high mean value at 30-200 s time-phase,with a minimum value of 3.85 mm and a maximum value of 17.91 mm.The mean value and standard deviation of TRE of the superfacial gold marker points were all higher than those of the internal points.In case of registration by DIR the Dice coefficients had medium-strength correlations with the TRE mean values of the internal points and all the points(0.4＜r＜0.6).In case of registration by HY-DIR the Dice coefficients did not correlated with the TRE mean values(r＜0.2).In terms of TRE mean value there were significant difference between DIR with gold marker group and HY-DIR with gold marker group(P=0.026)and between DIR with gold marker group and DIR without gold marker group(P=0.036).Conclusion When MMI software is used for self-addaptive radiotherapy registration,satisfactory results are obtained at 30 s time-phase;at 60-90 s time-phase(volume shrinkage lower than 20％),some low registration errors occur and need artificial correction;at 100-200 s time-phase(volume shrinkage higher than 20％),high registration errors appear while the registration with gold markers be haves better than that without gold markers and DIR gains advantages over HY-DIR.[Chinese Medical Equipment Journal,2025,46(2):49-55]
