Thickbox with Ajax loaded images
You need to add the behaviors like this:

Drupal.attachBehaviors($('.ajax-container'));


So looks like in your case it would be:

Drupal.attachBehaviors($('.brick-filter-test'));


This should do the trick

$.get('/brick_filter/test/', function(result){
  element.innerHTML = data;
  Drupal.attachBehaviors($('.brick-filter-test'));
});