Image by Flickr user spiralstares

Since 1996, William Burke, 53, has been using plethysmograph (PPG) and other controversial testing practices in an attempt to prevent child abuse. While his methods have pure intentions, they are not always seen as positive; in fact, one Lowcountry judge dubbed Burke as a "witch doctor" at one time.

So what in the world is PPG technology? Essentially, it's a penile lie detector. It measures arousal while the patient is exposed to photographs and/or audio recordings.

Burke uses data from PPG and other tests to make risk recommendations. He explains: "If a man accused of molesting his stepdaughter is brought in and tests positive for arousal to young girls, I will suggest he not be allowed back home."

While Burke works with all kinds of patients, he says that about 80% of his work deals with men that have sexually abused children. Burke's goal? To stop child abusers.

The Post and Courier has a great in-depth report on this fascinating subject; read it here.