AUTHOR=Du Qing-Hua , Li Jian , Gan Yi-Xiu , Zhu Hui-Jun , Yue Hai-Ying , Li Xiang-De , Ou Xue , Zhong Qiu-Lu , Luo Dan-Jing , Xie Yi-Ting , Liang Qian-Fu , Wang Ren-Sheng , Liu Wen-Qi 

TITLE=Potential Defects and Improvements of Equivalent Uniform Dose Prediction Model Based on the Analysis of Radiation-Induced Brain Injury

JOURNAL=Frontiers in Oncology

VOLUME=Volume 11 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.743941

DOI=10.3389/fonc.2021.743941

ISSN=2234-943X

ABSTRACT=Purpose: To study the impact of dose distribution on volume-effect parameter and predictive ability of equivalent uniform dose (EUD) model, and to explore the improvements.
Methods and Materials: The brains of 103 nasopharyngeal carcinoma patients receiving IMRT were segmented according to dose distribution (brain and left/right half-brain for similar distributions but different sizes; VD with different D for different distributions). Predictive ability of EUDVD (EUD of VD) for radiation-induced brain injury was assessed by receiver operating characteristics curve (ROC) and area under the curve (AUC). The optimal volume-effect parameter a of EUD was selected when AUC was maximal (mAUC). Correlations between mAUC, a and D were analyzed by Pearson correlation analysis. Both mAUC and a in brain and half-brain were compared using paired samples t-tests. The optimal DV and VD points were selected for a simple comparison.
Results: The mAUC of brain/half-brain EUD was 0.819/0.821 and the optimal a value was 21.5/22. As D increased, mAUC of EUDVD increased and a decreased. The mAUC reached maximum when D was 50-55Gy, and a was always 1 when D≥55Gy. The difference of mAUC/a between brain and half-brain was not significant. In the a range of 1 to 22, AUC of EUDV55Gy in brain/half-brain (0.857-0.830/0.845-0.830) was always larger than that of EUD (0.681-0.819/0.691-0.821). The AUCs of optimal dose/volume points were 0.801 (brain D2.5cc), 0.823 (brain V70Gy), 0.818 (half-brain D1cc) and 0.827 (half-brain V69Gy), respectively. Mean dose (equal to EUDVD with a=1) of high-dose volume (V50Gy-V60Gy) was superior to traditional EUD and dose/volume points.
Conclusion: Volume-effect parameter of EUD is variable and related to dose distribution. EUD with large low-dose volume may not be better than simple dose/volume points. Critical-dose-volume EUD could improve the predictive ability and has an invariant volume-effect parameter. Mean dose may be the case in which critical-dose-volume EUD has the best predictive ability.