Php & NTLM

I was advised to use the NTLM module for apache for authentication. However, I am really looking for a way to authenticate during the run of Php. I am aware that the NTLM module works before the page gets called, very similar to the authentication process provided on Zend.com's website tutorial. My question is, can I use NTLM to do the authentication and then use the PHP_AUTH_USER to get the user name (which is really what I need, the authentication process is necessary only to make sure the user is (a) who they say the are and (b) a valid user). Does anyone know if this is possible? Thank you, Ben Meyer