diff --git a/magick/threshold.c b/magick/threshold.c
index b581498..f73f6b8 100644
--- a/magick/threshold.c
+++ b/magick/threshold.c
@@ -933,7 +933,7 @@
   }
 
   /* The map has been found -- Allocate a Threshold Map to return */
-  map = (ThresholdMap *)AcquireQuantumMemory(1,sizeof(ThresholdMap));
+  map = (ThresholdMap *)AcquireMagickMemory(sizeof(ThresholdMap));
   if ( map == (ThresholdMap *)NULL )
     ThrowFatalException(ResourceLimitFatalError,"UnableToAcquireThresholdMap");
   map->map_id = (char *)NULL;