def load_structures
      if @dcm[STRUCTURE_SET_ROI_SQ] && @dcm[ROI_CONTOUR_SQ] && @dcm[RT_ROI_OBS_SQ]
        # Load the information in a nested hash:
        item_group = Hash.new
        @dcm[STRUCTURE_SET_ROI_SQ].each do |roi_item|
          item_group[roi_item.value(ROI_NUMBER)] = {:roi => roi_item}
        end
        @dcm[ROI_CONTOUR_SQ].each do |contour_item|
          item_group[contour_item.value(REF_ROI_NUMBER)][:contour] = contour_item
        end
        @dcm[RT_ROI_OBS_SQ].each do |rt_item|
          item_group[rt_item.value(REF_ROI_NUMBER)][:rt] = rt_item
        end
        # Create a ROI instance for each set of items:
        item_group.each_value do |roi_items|
          Structure.create_from_items(roi_items[:roi], roi_items[:contour], roi_items[:rt], self)
        end
      else
        RTKIT.logger.warn "The structure set contained one or more empty ROI sequences. No ROIs extracted."
      end
    end
def load_structures
      if @dcm[STRUCTURE_SET_ROI_SQ] && @dcm[ROI_CONTOUR_SQ] && @dcm[RT_ROI_OBS_SQ]
        # Load the information in a nested hash:
        item_group = Hash.new
        @dcm[STRUCTURE_SET_ROI_SQ].each do |roi_item|
          item_group[roi_item.value(ROI_NUMBER)] = {:roi => roi_item}
        end
        @dcm[ROI_CONTOUR_SQ].each do |contour_item|
          item_group[contour_item.value(REF_ROI_NUMBER)][:contour] = contour_item
        end
        @dcm[RT_ROI_OBS_SQ].each do |rt_item|
          item_group[rt_item.value(REF_ROI_NUMBER)][:rt] = rt_item
        end
        # Create a ROI instance for each set of items:
        item_group.each_value do |roi_items|
          Structure.create_from_items(roi_items[:roi], roi_items[:contour], roi_items[:rt], self)
        end
      else
        RTKIT.logger.warn "The structure set contained one or more empty ROI sequences. No ROIs extracted."
      end
    end
Loads the ROI Items contained in the structure set and creates ROI
 and POI instances, which are referenced to this structure set.