diff --git a/images.toml b/images.toml
index efa5e00..4e170be 100644
--- a/images.toml
+++ b/images.toml
@@ -44,7 +44,7 @@ subread = '2.0.6'
 talos = '6.1.0'  # release to build, image names should have specific releases. Can build by naming side-branch
 trtools = '6.0.2'
 trtools_hope_version = 'skip-if-monomorphic'  # specific branch name
-trtools_nonlinear_sum = 'master'
+trtools_nonlinear_sum = 'piecewise-reg'
 vep_105 = '105.0'
 vep_110 = 'release_110.1'
 verifybamid = '2.0.1'
diff --git a/trtools_nonlinear_sum/Dockerfile b/trtools_nonlinear_sum/Dockerfile
new file mode 100644
index 0000000..147d577
--- /dev/null
+++ b/trtools_nonlinear_sum/Dockerfile
@@ -0,0 +1,13 @@
+FROM python:3.10-bullseye
+
+ARG VERSION=${VERSION:-piecewise-reg}
+ARG GIT_REPO=https://github.com/populationgenomics/TRTools-segreg.git
+
+# Install necessary packages and clean up to reduce image size
+RUN apt-get update && apt-get install --no-install-recommends -y \
+    git curl bzip2 zip && \
+    rm -rf /var/lib/apt/lists/* && \
+    rm -rf /var/cache/apt/*
+
+# Install Python packages including piecewise_regression
+RUN pip install --no-cache-dir metamist piecewise_regression git+${GIT_REPO}@${VERSION}