def dcm_collimator1(axis)
      value = self.send("collimator_#{axis}1").to_f * 10
      mode = self.send("field_#{axis}_mode")
      if mode && mode.upcase == 'SYM' && value > 0
        -value
      else
        value
      end
    end
def dcm_collimator1(axis)
      value = self.send("collimator_#{axis}1").to_f * 10
      mode = self.send("field_#{axis}_mode")
      if mode && mode.upcase == 'SYM' && value > 0
        -value
      else
        value
      end
    end
Converts the collimator attribute to proper DICOM format.

 @param [Symbol] axis a representation for the axis of interest (x or y)
 @return [Float] the DICOM-formatted collimator attribute