diff --git a/api/dicom-web/controller/PAM-RS/service/delete-patient.service.js b/api/dicom-web/controller/PAM-RS/service/delete-patient.service.js
index e6ad0cd3..b1eb680a 100644
--- a/api/dicom-web/controller/PAM-RS/service/delete-patient.service.js
+++ b/api/dicom-web/controller/PAM-RS/service/delete-patient.service.js
@@ -11,7 +11,7 @@ class DeletePatientService {
 
     async delete() {
         let { patientID } = this.request.params;
-        let patient = await PatientModel.findOne({ patientID});
+        let patient = await PatientModel.findOneByPatientID(patientID);
         if (!patient) {
             throw new DicomWebServiceError(
                 DicomWebStatusCodes.NoSuchObjectInstance,
diff --git a/models/mongodb/models/patient.model.js b/models/mongodb/models/patient.model.js
index 9905beb4..3c29d878 100644
--- a/models/mongodb/models/patient.model.js
+++ b/models/mongodb/models/patient.model.js
@@ -70,6 +70,11 @@ let patientSchemaOptions = _.merge(
 
                 return patient;
             },
+            findOneByPatientID: async function(patientID) {
+                return await mongoose.model("patient").findOne({
+                    patientID
+                });
+            },
             /**
              * 
              * @param {string} patientID