diff --git a/IRaCIS.Core.Application/Service/QC/QCOperationService.cs b/IRaCIS.Core.Application/Service/QC/QCOperationService.cs
index f3338c873..2d460b07b 100644
--- a/IRaCIS.Core.Application/Service/QC/QCOperationService.cs
+++ b/IRaCIS.Core.Application/Service/QC/QCOperationService.cs
@@ -319,7 +319,7 @@ namespace IRaCIS.Core.Application.Image.QA
         /// <returns></returns>
         /// <exception cref="BusinessValidationFailedException"></exception>
         [HttpPut]
-        public async Task<IResponseOutput> AuditImageBack(Guid iamgeBackRecordId, bool isAgree,string resultRemark)
+        public async Task<IResponseOutput> AuditImageBack(Guid iamgeBackRecordId, bool isAgree,string? resultRemark)
         {
             var backRecord = (await _subjectVisitImageBackRecordReposiotry.FirstOrDefaultAsync(t => t.Id == iamgeBackRecordId)).IfNullThrowException();
 
@@ -414,7 +414,7 @@ namespace IRaCIS.Core.Application.Image.QA
             }
 
             backRecord.AuditTime = DateTime.Now;
-            backRecord.ResultRemark = resultRemark;
+            backRecord.ResultRemark = resultRemark??string.Empty;
             await _subjectVisitRepository.SaveChangesAsync();
 
             return ResponseOutput.Ok();