diff --git a/IRaCIS.Core.Application/Service/ImageAndDoc/DownloadAndUploadService.cs b/IRaCIS.Core.Application/Service/ImageAndDoc/DownloadAndUploadService.cs
index 07f37c331..625d049ba 100644
--- a/IRaCIS.Core.Application/Service/ImageAndDoc/DownloadAndUploadService.cs
+++ b/IRaCIS.Core.Application/Service/ImageAndDoc/DownloadAndUploadService.cs
@@ -2457,18 +2457,18 @@ namespace IRaCIS.Core.Application.Service.ImageAndDoc
                       IsUrgent = t.IsUrgent,
 
                       LatestDownloadTime = t.TrialImageDownloadList.Where(t => t.CreateUserRole.UserTypeEnum == UserTypeEnum.IndependentReviewer)
-                      .OrderByDescending(t => t.CreateTime).Select(t => t.CreateTime).FirstOrDefault(),
+                      .OrderByDescending(t => t.CreateTime).Select(t => (DateTime?)t.CreateTime).FirstOrDefault(),
 
                       LatestUploadTime = t.SubjectVisitList
                             .Where(v => v.SubmitState == SubmitStateEnum.Submitted && v.CheckState == CheckStateEnum.CVPassed)
                             .SelectMany(v => v.TaskStudyList)
-                            .Select(s => s.CreateTime)  // 假设字段名为 CreateTime，根据实际情况调整
+                            .Select(s => (DateTime?)s.CreateTime)  // 假设字段名为 CreateTime，根据实际情况调整
                             .Union(
                                 t.SubjectVisitList
                                     .Where(v => v.SubmitState == SubmitStateEnum.Submitted && v.CheckState == CheckStateEnum.CVPassed)
                                     .SelectMany(v => v.NoneDicomStudyList)
                                     .Where(n => n.ImageLabelNoneDicomFileList.Any())
-                                    .Select(s => s.CreateTime)  // 假设字段名为 CreateTime，根据实际情况调整
+                                    .Select(s => (DateTime?)s.CreateTime)  // 假设字段名为 CreateTime，根据实际情况调整
                             )
                             .OrderByDescending(time => time)
                             .FirstOrDefault(),