diff --git a/pyproject.toml b/pyproject.toml
index 72d221c..5954a25 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -67,14 +67,22 @@ name = "pytorch-cu126"
 url = "https://download.pytorch.org/whl/cu126"
 explicit = true
 
+[[tool.uv.index]]
+name = "pytorch-cu118"
+url = "https://download.pytorch.org/whl/cu118"
+explicit = true
+
 [tool.uv.sources]
 torch = [
+  { index = "pytorch-cu118", marker = "python_version == '3.9' and (sys_platform == 'linux' or sys_platform == 'win32')" },
   { index = "pytorch-cu126", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
 ]
 torchvision = [
+  { index = "pytorch-cu118", marker = "python_version == '3.9' and (sys_platform == 'linux' or sys_platform == 'win32')" },
   { index = "pytorch-cu126", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
 ]
 torchaudio = [
+  { index = "pytorch-cu118", marker = "python_version == '3.9' and (sys_platform == 'linux' or sys_platform == 'win32')" },
   { index = "pytorch-cu126", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
 ]