private function buildRadiusOptions()
    {
        if (!$this->radius || !isset($GLOBALS['TL_DCA'][$this->strTable]['fields'][$this->radius])) {
            return null;
        }

        $options = [
            'element'      => 'ctrl_' . $this->radius,
            'min'          => 0,
            'max'          => 0,
            'defaultValue' => 0
        ];

        if (isset($GLOBALS['TL_DCA'][$this->strTable]['fields'][$this->radius]['eval'])) {
            $config = $GLOBALS['TL_DCA'][$this->strTable]['fields'][$this->radius]['eval'];

            $options['min']          = isset($config['minval']) ? (int) $config['minval'] : 0;
            $options['max']          = isset($config['maxval']) ? (int) $config['maxval'] : 0;
            $options['defaultValue'] = isset($config['default']) ? (int) $config['default'] : 0;
            $options['steps']        = isset($config['steps']) ? (int) $config['steps'] : 0;
        }

        return $options;
    }