diff --git a/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsMedicationStatementMapper.java b/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsMedicationStatementMapper.java
index aba9ef67..7b86a297 100644
--- a/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsMedicationStatementMapper.java
+++ b/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsMedicationStatementMapper.java
@@ -2,6 +2,7 @@
 
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import org.hl7.fhir.r4.model.*;
 import org.miracum.streams.ume.obdstofhir.FhirProperties;
 import org.miracum.streams.ume.obdstofhir.lookup.SYSTTherapieartCSLookup;
@@ -123,7 +124,7 @@ public MedicationStatement createSystemtherapyMedicationStatement(
       String softwareId,
       Meldeanlass meldeanlass,
       String substance,
-      HashSet<String> substances) {
+      Set<String> substances) {
 
     var systemTherapy = meldung.getMenge_SYST().getSYST();
 
diff --git a/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsProcedureMapper.java b/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsProcedureMapper.java
index 657a435c..ce7a0b33 100644
--- a/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsProcedureMapper.java
+++ b/src/main/java/org/miracum/streams/ume/obdstofhir/mapper/ObdsProcedureMapper.java
@@ -141,7 +141,7 @@ public Procedure createOpProcedure(
       String senderId,
       String softwareId,
       String opsCode,
-      HashSet<String> distinctOpsSet) {
+      Set<String> distinctOpsSet) {
 
     var op = meldung.getMenge_OP().getOP();
 
@@ -306,7 +306,7 @@ public Procedure createRadiotherapyProcedure(
       Meldeanlass meldeanlass,
       Bestrahlung radio,
       Tupel<Date, Date> timeSpan,
-      HashSet<Bestrahlung> distinctPartialRadiations) {
+      Set<Bestrahlung> distinctPartialRadiations) {
 
     var radioTherapy = meldung.getMenge_ST().getST();