Lee Na-geum has been calling for surveillance cameras to be mandatory in hospital operating theaters.
Her lonely battle began five years ago, when her son died due to excessive bleeding. during plastic surgery.
Lee says, the medical malpractice, that led to her son's death, wouldn't have been proven in court, if it weren't for CCTV footage.
"I broke down the footage into each second to make a timeline - like who went in and out, and what they did. And I found out, a nurse's aide did the procedure as the surgeon left critical evidence that judges could not deny."
Lee's son, Kwon Dae-hee, was operated on, by so-called "ghost surgeons" staff often unqualified substituting for doctors so that multiple procedures can be done at once.
And, Lee had to do more than just bringing criminal charges against those involved.
She demanded a change in the law.
"While cleaning his things, I found my son's bucket list, and number 15 says "leaving my mark on the world with my name." It seemed like his last wish. And I felt like he left the CCTV footage as his bequest, to help prevent further victims like him."
And so-called "the Kwon Dae-hee law" has been officially passed by lawmakers on Tuesday, making South Korea the first country to adopt such legislation.
Under the law, hospitals are required to film procedures involving general anesthesia, at the request of patients or their guardian.
But there are several exceptions like for emergency operations or procedures involving high risk.
There will also be a two-year grace period before the law is fully implemented.
Patients association largely welcome the change, believing it could help prevent sexual assaults and medical malpractice.
But doctors remain resistant,saying it infringes on their rights,. and harms doctor-patient trust.
Lee Kyung-eun, Arirang News.