Add gETU feature

pyradiomics_radler/myfirstorder.py

@@ -126,3 +126,25 @@ class MyRadiomicsFirstOrder(MyRadiomicsFeaturesBase):
         csh = numpy.flipud(numpy.cumsum(numpy.flipud(bins)) / nVoxel)
         return numpy.sum(csh / nBins)
 
+    def getgETUFeatureValue(self):
+        r"""
+        **24. gETU**
+
+        Generalized effective total uptake, with parameter a = 0.25 as defined by Rahim et al.
+
+        - input: 3D array representing the PET volume in SUV format, with 
+                voxels outside the ROI set to NaNs.
+
+        .. note::
+        Extracted from PET scans and not used in the CT feature set.
+        """
+        ROIPet = self.imageArray
+        mask = self.maskArray
+        ROIPet[~mask] = numpy.nan
+
+        a = 0.25
+        n_voxels = numpy.sum(ROIPet[~numpy.isnan(ROIPet)])
+        ROIPet = ROIPet ** a
+
+        return numpy.sum(ROIPet[~numpy.isnan(ROIPet)] / n_voxels) ** (1 / a)
+