diff --git a/dap/algos/radprof.py b/dap/algos/radprof.py
index 9cdd601..ed7c5be 100644
--- a/dap/algos/radprof.py
+++ b/dap/algos/radprof.py
@@ -21,7 +21,7 @@ def calc_radial_integration(results, data, pixel_mask_pf, center, rad, norm):
     if apply_threshold and all(k in results for k in ("threshold_min", "threshold_max")):
         threshold_min = float(results["threshold_min"])
         threshold_max = float(results["threshold_max"])
-        data = np.copy(data) # do the following in-place changes on a copy
+        data = data.copy() # do the following in-place changes on a copy
         data[data < threshold_min] = np.nan
         #TODO: skipping max is a guess, but not obvious/symmetric -- better to ensure the order min < max by switching them if needed
         if threshold_max > threshold_min: