KLTV TV News, Channel 7 (CBS), Tyler, Feb. 13, 2007 HUNTSVILLE - Behind a barbed-wire fence is the Estelle Unit in Huntsville. Unlike any prison you've ever imagined, it's an all-encompassing medical facility run by the University of Texas Medical Branch. They provide state-of-the-art care to all inmates in the Texas Department of Correction with an average of 3 million patient encounters a year. Chief Physician Owen Murray says, "That's dieticians, nurses, mental health, dental, medical, passing meds, TB tests. The gamut of health care services, we provide for this offender population." The cost of care for an inmate in the general population is $7.66/day, but when inmates reach the age of 55, that figure skyrockets to about $22/day. With nearly 10,000 of those older inmates in Texas prisons, it adds up to nearly 80 million dollars each year. According to UTMB, the older population is the fastest growing segment in the prison system, outpacing their younger counterparts at a rate of three to one.  "It's probably because of longer prison sentences. People are staying in prison longer, and therefore, they're growing old in prison. The feeblest inmates wind up in a 60-bed geriatric unit. 74 year old Perry Waddle spends his days listening to southern gospel music and reading his Bible. He was convicted of robbery in 1967 and was released on parole in 1997. In 2000, he was arrested for selling and possessing cocaine. At 68 years old, he was sent back to prison.