diff --git a/IRaCIS.Core.Application/Service/Common/TrialImageDownloadService.cs b/IRaCIS.Core.Application/Service/Common/TrialImageDownloadService.cs
index eaad74bcb..6ba580e20 100644
--- a/IRaCIS.Core.Application/Service/Common/TrialImageDownloadService.cs
+++ b/IRaCIS.Core.Application/Service/Common/TrialImageDownloadService.cs
@@ -61,8 +61,24 @@ namespace IRaCIS.Core.Application.Service
             try
             {
                 await using var source = await sourceFactory();
+
+                // 【关键修复】将 OSS 流缓冲到 MemoryStream
+                using var bufferedStream = new MemoryStream();
+
+                if (source.CanSeek)
+                {
+                    source.Position = 0;
+
+                }
+                else
+                {
+                    // 完全复制到内存流
+                    await source.CopyToAsync(bufferedStream);
+                    bufferedStream.Position = 0; // 重置位置
+                }
+
                 // 如果你是从 stream 打开
-                var dicomFile = await DicomFile.OpenAsync(source);
+                var dicomFile = await DicomFile.OpenAsync(source.CanSeek ? source : bufferedStream);
 
                 //获取像素是否为封装形式
                 var syntax = dicomFile.Dataset.InternalTransferSyntax;
@@ -70,11 +86,14 @@ namespace IRaCIS.Core.Application.Service
                 //对于封装像素的文件做转换
                 if (syntax.IsEncapsulated)
                 {
+                    #region 开始方式
+
                     // 获取 Pixel Data 标签
                     var pixelData = DicomPixelData.Create(dicomFile.Dataset);
 
                     // 创建一个新的片段序列
                     var newFragments = new DicomOtherByteFragment(DicomTag.PixelData);
+
                     // 获取每帧数据并封装为单独的片段
                     for (int n = 0; n < pixelData.NumberOfFrames; n++)
                     {
@@ -82,13 +101,11 @@ namespace IRaCIS.Core.Application.Service
                         newFragments.Fragments.Add(new MemoryByteBuffer(frameData.Data));
                     }
 
-                    var frag = dicomFile.Dataset.GetDicomItem<DicomOtherByteFragment>(DicomTag.PixelData);
-
-                    var originOffsetTable = frag?.OffsetTable;
-
-                    newFragments.OffsetTable.AddRange(originOffsetTable?.ToArray());
                     // 替换原有的片段序列
                     dicomFile.Dataset.AddOrUpdate(newFragments);
+
+                    #endregion
+
                 }
 
                 await dicomFile.SaveAsync(output);
diff --git a/IRaCIS.Core.Application/Service/ImageAndDoc/StudyService.cs b/IRaCIS.Core.Application/Service/ImageAndDoc/StudyService.cs
index c38ebff88..70458f08a 100644
--- a/IRaCIS.Core.Application/Service/ImageAndDoc/StudyService.cs
+++ b/IRaCIS.Core.Application/Service/ImageAndDoc/StudyService.cs
@@ -104,11 +104,11 @@ namespace IRaCIS.Core.Application.Service.ImageAndDoc
                         newFragments.Fragments.Add(new MemoryByteBuffer(frameData.Data));
                     }
 
-                    var frag = dicomFile.Dataset.GetDicomItem<DicomOtherByteFragment>(DicomTag.PixelData);
+                    //var frag = dicomFile.Dataset.GetDicomItem<DicomOtherByteFragment>(DicomTag.PixelData);
 
-                    var originOffsetTable = frag?.OffsetTable;
+                    //var originOffsetTable = frag?.OffsetTable;
 
-                    newFragments.OffsetTable.AddRange(originOffsetTable?.ToArray());
+                    //newFragments.OffsetTable.AddRange(originOffsetTable?.ToArray());
                     // 替换原有的片段序列
                     dicomFile.Dataset.AddOrUpdate(newFragments);
                 }