diff --git a/modules/nf-core/numorph/3dunet/Dockerfile b/modules/nf-core/numorph/3dunet/Dockerfile
index 9e8bf8fce748..a25c7749c0ab 100644
--- a/modules/nf-core/numorph/3dunet/Dockerfile
+++ b/modules/nf-core/numorph/3dunet/Dockerfile
@@ -1,5 +1,5 @@
 ## optimized nvidia base container for older python and tensorflow
-FROM nvcr.io/nvidia/tensorflow:20.10-tf1-py3
+FROM nvcr.io/nvidia/tensorflow:20.10-tf1-py3@sha256:9206ed88af83ca5dd4ba6bd95cf6aff6f8432ce98699aa43c216222747dc4500
 
 ARG NUMORPH_3DUNET_VERSION="1.0.9"