Palo Alto, Calif.-based Pulmonx raised $20 million in a second-round funding, VentureWire reports (subscription required).

The startup is one of several device makers hoping to pioneer new medical techniques in the field of “interventional pulmonology.” Much like interventional cardiology, in which non-surgeons perform procedures such as angioplasty and stenting to open blocked arteries, interventional pulmonology aims to give lung specialists new tools to treat lung problems such as emphysema in their offices. Patients, of course, could benefit from quicker recovery times and avoiding hospitals as well, at least if the procedures are proven to be equal or superior to existing techniques.

According to VentureWire:

Richard M. Ferrari, managing director of De Novo, said that these companies, like Pulmonx, are looking to replace the current mode of treatment: lung volume reduction surgery. “It’s an incredibly invasive procedure,” he said. “So the concept of having an office-based procedure is irresistible.”

Pulmonx’s technology involves the insertion of a one-way valve, shutting off diseased portions of the lung. Ferrari said that the technique is part of a growing field of interventional pulmonology, which, like the more established field of interventional cardiology, uses catheter-based treatments for diseases.

Pulmonx has been in trials outside of the U.S., Ferrari said, and plans to begin human implantations in the U.S. later this year or early next year. “The $20 million will take them well into their clinical trials,” he said.

The round was led by De Novo Ventures. Others involved in the round include new investor Latterell Venture Partners and existing investors Montreux Equity Partners and MedVenture Associates.