diff --git a/csst_ifs_sim/csst_ifs_sim.py b/csst_ifs_sim/csst_ifs_sim.py
index a60d0d7ab1c36810b712e369a3322cf0ecd759ce..9fdbca25cd8c01f2507ca1ecfe397c70bff8cc3e 100644
--- a/csst_ifs_sim/csst_ifs_sim.py
+++ b/csst_ifs_sim/csst_ifs_sim.py
@@ -2541,7 +2541,7 @@ class IFSsimulator():
 
         self.log.debug('Starting to apply radiation damage model...')
         # at this point we can give fake data...
-        cti = CTI.CDM03bidir(self.information, [], log=self.log)
+        cti = CDM03bidir(self.information, [], log=self.log)
 
         # here we need the right input data
         self.image_b = cti.applyRadiationDamage(self.image_b.copy(
@@ -2550,7 +2550,7 @@ class IFSsimulator():
 
         self.log.debug('Starting to apply radiation damage model...')
         # at this point we can give fake data...
-        cti = CTI.CDM03bidir(self.information, [], log=self.log)
+        cti = CDM03bidir(self.information, [], log=self.log)
         # here we need the right input data
         self.image_r = cti.applyRadiationDamage(self.image_r.copy(
         ).transpose(), iquadrant=self.information['quadrant']).transpose()