public function imageAction()
 {
     $this->getResponse()->setHeader('Content-Type', 'image/png');
     $this->_helper->layout->disableLayout();
     $this->_helper->viewRenderer->setNoRender(true);
     $id = $this->_getParam('id');
     $avatar = Application_Model_M_Hospital::getAvatar($id);
     echo $avatar;
 }