After doctors diagnosed Paula Estrada with breast cancer in 2009, the then 41-year-old Argentine decided she would not only beat the disease, but would do so without losing her long blonde hair to the ravages of chemotherapy.

At her home in Buenos Aires, Estrada, a graphic designer by profession, set about creating a makeshift cooling cap out of ice packs to keep her scalp cold - and ward off hair loss.

It worked, and "nobody realized that I was undergoing chemotherapy," said Estrada, now 54.

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Scalp cooling, a way to constrict blood vessels and keep chemotherapy drugs from reaching hair follicles, has existed in some form for decades. The Paxman Scalp Cooling cap, for example, was introduced in Britain in 1997 and earned U.S. FDA approval in 2017.

Cooling chemo cap

Paula Estrada shows off her cooling cap that helped her keep her hair while she was going through chemo therapy, and is now helping others do the same by offering the caps for only $2. (REUTERS/Matias Baglietto)

But in 2009, cooling caps were an unknown in Argentina, Estrada said.

"When I finished, I said 'I'm not going to keep this for myself, I want everyone to have this as a possibility," she recalled.

Estrada's 'Quimo con pelo' cap can be made with gels that cost as little as $2 - a lifesaver in a country facing economic struggles and where alternative cooling caps can cost $100 a session.

On social media, patients in Argentina and around the world share instructions on how to make the caps and donate them when they're finished.

The caps must be used beginning with the first chemo session, kept at -4 degrees Fahrenheit (-20 degrees Celsius), and changed every 30 minutes.

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"It's worth it," said Mariangeles Fernandez, a 48-year-old liver cancer patient. "It lets you fight the disease in a different way."

Estrada, who is now writing a book about her experience, says she hears from patients every day whose cancer journeys have been improved by the caps.

"I think the (cap) has been the key to my state of mind," said Elsa Ram, a 64-year-old retiree with breast cancer. "This is a big part of a good treatment."