Is Gary Kao a renegade physician, or a sacrificial lamb - or maybe just a doctor who was allowed to get in over his head?

Kao is the only person whom officials have identified in the unfolding scandal over substandard radioactive seed implants at the Philadelphia VA Medical Center.

As the radiation oncologist who did most of the implants, Kao played a central role. But a huge cast of actors supported and directed him - week after week, for six years - until the VA suspended the program a year ago.

Those actors included a medical physicist with little experience in developing implant treatment plans, a radiation-safety committee that allowed crucial radiation-dosage calculations to go undone, and Nuclear Regulatory Commission inspectors who let Kao revise two patients' treatment plans to avoid reporting medical errors, according to the Veterans Affairs investigation report.

From top to bottom, that report concluded, there was a lack of concern for safety and accountability.

That's a chilling denunciation, considering that the VA worked with eminent institutions - the University of Pennsylvania Health System and the NRC - to create and run the high-tech brachytherapy program. The treatment involves permanently implanting tiny radioactive beads in the prostate gland. The beads emit cancer-killing radiation for about 10 months.

Of 114 prostate-cancer patients who underwent brachytherapy, 92 received suboptimal radiation to the prostate or potentially harmful levels to nearby organs or both.

Kao, who took a leave of absence from Penn on June 24, testified last week before a Senate hearing run by Sen. Arlen Specter (D., Pa.). Kao decried the media's portrayal of him as a "rogue" and complained that he was being scapegoated.

Some observers say he has a point. "I don't condone the mistakes he made, but I also don't blame him for feeling that he is being made a scapegoat," said Peter Crane, an NRC lawyer for 23 years and now a sharp critic of the agency. "This was a systemic failure, not the failure of one individual."

Three people with insight into this systemwide breakdown were listed as witnesses at the Senate hearing: Mary Moore, the Philadelphia VA's radiation-safety officer; Joel Maslow, chair of the VA's radiation-safety committee and a Penn infectious-disease specialist; and Richard Whittington, a Penn radiation oncologist who did a small number of the brachytherapy implants.

They were not questioned by the senators, nor were they allowed to speak to reporters.

Had they cared to, the senators could have asked why the radiation-safety committee allowed a computer-interface problem to go uncorrected for a year, jeopardizing patients' treatments. Because of the computer problem, patients' actual postimplant radiation doses were not calculated, so no one knew whether they were getting the prescribed amount.

The NRC, another big player in the mess, says in news releases that it responded "aggressively and decisively to the medical errors" at the VA.

But the commission's public records appear to belie this.

In 2003 and 2005, the NRC investigated two mistakes that the VA reported to it. In both cases, Kao injected half of the radioactive seeds that were meant for the prostate into the patient's bladder. Although a urologist was able to retrieve the errant seeds, the patients' prostate glands obviously received less radiation than prescribed.

The NRC concluded there was no "medical event" - the regulatory euphemism for medical error - because the patients' treatment plans were revised to indicate how few seeds actually wound up in their prostates.

In light of the scandal, the NRC has reviewed both cases and concluded they were indeed medical errors.

"It is shocking that a doctor seems to have mishandled procedures" so often, Crane said. "But it is even more shocking that the NRC knew of the problem in 2003, saw it recur in 2005, and didn't take action until 2008."

NRC spokeswoman Viktoria Mitlyng said the agency was responsible for the lax care only to the degree that it misplaced its trust in the VA. When the brachytherapy program was created in 2002, she explained, the NRC allowed the VA to create the National Health Physics Program, which was supposed to monitor treatment and report any problems to the NRC. In effect, the VA was its own watchdog.

"Obviously," Mitlyng said, the National Health Physics Program "didn't work as well as we expected. We will be looking at increasing our own inspections of the VA."

In his testimony, Kao pointed out that he was part of a team - although he didn't name any teammates. Another part of his defense sounded less persuasive: He said that in 2002, the NRC had no definition of a reportable medical event. He also said the NRC never trained his team "on this issue."

In fact, a simple Google search (NRC report medical event) brings up the reporting rule, which applies to radioisotope medical use in general, not just brachytherapy.

The rule, put into effect by the NRC in 1980, defines a medical event as radiation to a treatment site that deviates by more than 20 percent from the prescribed dose, and radiation to surrounding tissue that is 50 percent or more above the expected dose.

The rule says these errors must be reported to the patient within 24 hours and to the NRC within 15 days.

Kao also contended that the definition of a medical event keeps evolving and is "a subject of debate" - which is true.

In 2005, for example, the NRC proposed a revised definition aimed at reducing the number of implants considered to have errors. Currently, too many dosage deviations that are medically meaningless have to be reported, according to an NRC advisory committee headed by Temple University radiologist Leon Malmud.

So far only a few of the VA's 114 brachytherapy patients have come forward to complain and file liability claims.

Ronald Goans, a radiation-medicine expert hired by the NRC, took a close look at 24 cases - 10 overdoses and 14 underdoses - and then asked the patients whether they had any lasting bad effects.

In his December 2008 report, Goans said most of the overdosed patients were doing well and had no evidence of prostate cancer. Three of the underdosed patients had prostate cancer and "were felt to be treatment failures."

Goans was also "very impressed with the current staff" at the VA.

"I would not foresee a recurrence of the situation seen in 2002-2008," he wrote.