Impact of the accuracy of automatic tumour functional volume delineation on radiotherapy treatment planning

Amandine Le Maitre, Mathieu Hatt, Olivier Pradier, Catherine Cheze-le Rest, Dimitris Visvikis
2012 Physics in Medicine and Biology  
In the past few years several automatic and semi-automatic PET segmentation methods for target volume definition in radiotherapy have been proposed. The objective of this study is to compare different methods in terms of dosimetry. For such comparison, a gold-standard is needed. For this purpose realistic GATE simulated PET images were used. Three lung cases and three H&N cases were designed with various shapes, contrasts and heterogeneities. Four 5 different segmentation approaches were
more » ... d: fixed and adaptive threshold, a fuzzy C-Mean and the fuzzy locally adaptive Bayesian method. For each of these target volumes an IMRT treatment plan was defined. The different algorithms and resulting plans were compared in terms of segmentation errors and ground-truth volume coverage using different metrics (V 95 , D 95 , homogeneity index and conformity index). The major differences between 10 threshold based methods and automatic methods occurred in the most heterogeneous cases. Within the two groups, the major differences occurred for low contrast cases. For homogeneous cases, equivalent ground-truth volume coverage were observed for all methods but for more heterogeneous cases significantly lower coverage was observed for thresholdbased methods. Our study demonstrates that significant dosimetry errors can be avoided by 15 using more advanced image segmentation methods. 3
doi:10.1088/0031-9155/57/17/5381 pmid:22864012 fatcat:ek2qlbnzjbafhipiny7eslpury