Module "Most Popular Post": truncate description after last word

Hi!

I've a question concerning the module "Most popular post": Is it possible (perhaps with a PHP-funkction) to truncate the description after a last (whole) word and not after x letters in the middle of words? It's not a big problem, but it would look a lot better...

The place to do this is in the helper.php:

$row->summary	= JString::substr( strip_tags( $summary ) , 0 , $params->get( 'textcount' ) ) . '...'; 

Thanks!