Comparison of dosimetry and radiobiology between volumetric modulated arc therapy and helical tomotherapy for craniospinal irradiation
10.13491/j.issn.1004-714X.2026.01.019
- VernacularTitle:螺旋断层与容积旋转调强技术在全中枢放疗中的剂量学及放射生物学比较
- Author:
Yongqing GE
1
;
Xiunan WANG
1
;
Hui YANG
1
;
Xiaofeng MU
1
Author Information
1. Department of Radiotherapy , Beijing Shijitan Hospital , Beijing 100038, China.
- Publication Type:OriginalArticles
- Keywords:
Craniospinal irradiation;
Volumetric modulated arc therapy;
Helical tomotherapy;
Normal tissue complication probability
- From:
Chinese Journal of Radiological Health
2026;35(1):113-119
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare the dosimetric and radiobiological differences of helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) in craniospinal irradiation. Methods The CT images of 15 patients who received craniospinal irradiation in our hospital were selected. The target volumes and organs at risk (OARs) were contoured, and HT and VMAT plans were designed. The dosimetric parameters of the two plans were compared. A Matlab program based on equivalent uniform dose was developed to calculate the normal tissue complication probability (NTCP). The NTCP values of the two plans were compared. Results The homogeneity index of the target volume in the HT group was better than that in the VMAT group, with values of 0.06 ± 0.01 and 0.08 ± 0.24, respectively, and the difference was statistically significant (P=0.03). However, there was no significant difference in the conformity index of the target volume (P>0.05). There were significant differences in key indicators (Dmean, V5, Dmax) of the lungs, liver, lens, and eyeballs between the two groups (P<0.05). Regarding OARs, the NTCP values of the lens, optic chiasm, lungs, and liver in the HT and VMAT groups were as follows: 0.04 ± 0.03 vs. 0.1 ± 0.06 in the left lens, 0.04 ± 0.06 vs. 0.1 ± 0.07 in the right lens, 0.16 (0.14-0.17) vs. 0.21 (0.18-0.24) in the optic chiasm, 3.89 × 10−4 (2.45 × 10−4-7.3 × 10−4) vs. 8.95 × 10−4 (5.19 × 10−4-1.75 × 10−3) in the lungs, and 3.45 × 10−8 (6.0 × 10−9-1.036 × 10−7) vs. 9.54 × 10−8 (1.70 × 10−8-2.056 × 10−7) in the liver; the HT group was superior to the VMAT group, and all differences were statistically significant (P<0.05). The NTCP values of the heart in the two groups were 1.35 × 10−8 (6.34 × 10−9-2.06 × 10−9) vs. 5.06 × 10−9 (2.29 × 10−9-7.9 × 10−9), significantly lower in the VMAT group than in the HT group (P<0.05). Conclusion HT has high homogeneity and consistency. The two plans have their own advantages in OAR protection. For OARs with no significant differences in physical dosimetry, NTCP results can be used as a reference. Therefore, comparing the dosimetric parameters and OAR NTCP of HT and VMAT plans can help select the optimal clinical treatment strategy.
