diff --git a/pkgs/development/python-modules/pyorthanc/default.nix b/pkgs/development/python-modules/pyorthanc/default.nix
index 0c33fc231974..a65d8d6b983b 100644
--- a/pkgs/development/python-modules/pyorthanc/default.nix
+++ b/pkgs/development/python-modules/pyorthanc/default.nix
@@ -3,7 +3,6 @@
   buildPythonPackage,
   fetchFromGitHub,
   pythonOlder,
-  pythonRelaxDepsHook,
   poetry-core,
   httpx,
   pydicom,
@@ -11,30 +10,25 @@
 
 buildPythonPackage rec {
   pname = "pyorthanc";
-  version = "1.16.1";
+  version = "1.18.0";
   disabled = pythonOlder "3.8";
 
-  format = "pyproject";
+  pyproject = true;
 
   src = fetchFromGitHub {
     owner = "gacou54";
     repo = pname;
     rev = "refs/tags/v${version}";
-    hash = "sha256-6l3L0YUAqedyRjlQ6K3SaAMdGK2C0AeKpJj6MyXi4RA=";
+    hash = "sha256-ObZjTiEB4a7ForsugzKZDdIsTEWOX1zbv53ZJ4AllHE=";
   };
 
-  nativeBuildInputs = [
-    pythonRelaxDepsHook
-    poetry-core
-  ];
+  build-system = [ poetry-core ];
 
-  propagatedBuildInputs = [
+  dependencies = [
     httpx
     pydicom
   ];
 
-  pythonRelaxDeps = [ "httpx" ];
-
   doCheck = false; # requires orthanc server (not in Nixpkgs)
 
   pythonImportsCheck = [ "pyorthanc" ];