Accurate segmentation of tumors in PET/CT images is important in computer-aided diagnosis and treatment of cancer. The key issue of such a segmentation problem lies in the effective integration of complementary information from PET and CT images. However, the quality of PET and CT images varies widely in clinical settings, which leads to uncertainty in the modality information extracted by networks. To take the uncertainty into account in multi-modal information fusion, this paper proposes a novel Multi-modal Evidential Fusion Network (MEFN) comprising a Cross-Modal Feature Learning (CFL) module and a Multi-modal Trusted Fusion (MTF) module. The CFL module reduces the domain gap upon modality conversion and highlights common tumor features, thereby alleviating the needs of the segmentation module to handle modality specificity. The MTF module utilizes mutual attention mechanisms and an uncertainty calibrator to fuse modality features based on modality uncertainty and then fuse the segmentation results under the guidance of Dempster-Shafer Theory. Besides, a new uncertainty perceptual loss is introduced to force the model focusing on uncertain features and hence improve its ability to extract trusted modality information. Extensive comparative experiments are conducted on two publicly available PET/CT datasets to evaluate the performance of our proposed method whose results demonstrate that our MEFN significantly outperforms state-of-the-art methods with improvements of 2.15% and 3.23% in DSC scores on the AutoPET dataset and the Hecktor dataset, respectively. More importantly, our model can provide radiologists with credible uncertainty of the segmentation results for their decision in accepting or rejecting the automatic segmentation results, which is particularly important for clinical applications. Our code will be available at https://github.com/QPaws/MEFN.

在计算机辅助肿瘤诊断和治疗中，精确分割PET/CT图像对癌症的诊断和治疗非常重要。本文提出了一种新颖的多模态证据融合网络（MEFN），通过交叉模态特征学习（CFL）模块和多模态可信融合（MTF）模块，以有效整合PET和CT图像中的互补信息并考虑模态不确定性，进而提高肿瘤分割的准确性和可信度。通过在两个公开的PET/CT数据集上进行广泛的对比实验，结果表明我们的方法在DSC评分上分别比现有方法提高了2.15%和3.23%。此外，我们的模型还能够为放射科医生提供可信的分割结果不确定性，对于临床应用非常重要。

多模态证据融合网络用于可信PET/CT肿瘤分割