This device is not specifically named on screen, simply referred to as a "device" by Phlox. However, in the final draft script of "Dead Stop", it was referred to initially as "a free-standing alien medical device" (with the last three words emboldened) and subsequently as "the drone".
CounselorDeanna Troi used hypnosis on both Worf and Doctor Beverly Crusher to determine what had caused a recent memory lapse during which they had committed actions which they had had no control over. Using the technique, it was found that both officers had been possessed by an unknown entity, which was ultimately revealed to be the Beta Renner cloud. (TNG: "Lonely Among Us")
In 2165 of an alternate timeline, this medical chamber was used by Denobulan doctor Phlox in an effort to destroy interspatial parasites which had infected Jonathan Archer's brain. The procedure which the chamber was involved in had been invented by Phlox over a period of nearly a decade and required energy levels so high they could be produced only in the reactor of a warp-capablestarship. As a result, the medical chamber was set up near the warp engine aboard Enterprise NX-01, connected to it via a series of conduits. Archer lay inside the medical chamber while a highly focused antiproton beam was fired at his head. The top of the medical chamber slid open to release him, and was operated by a control on the outside of the chamber.
The first time the chamber was used, the procedure was successful at eradicating a cluster of the parasites. During a battle between Enterprise and the Xindi shortly thereafter, however, the chamber was destroyed by debris, so Archer opted to instead create a subspace implosion, a process that eliminated not only the parasites but also the alternate timeline. (ENT: "Twilight")
This apparatus was referred to as a "medical chamber" in the final draft script of "Twilight". In the same teleplay, the chamber was established as having been designed and built by Phlox over the course of years.
In 2367, the host of Odan used this tool to scan his symbiont. The symbiont reacted by pushing outwards beneath the skin. (TNG: "The Host")
It is unclear what this tool actually does, how it stimulates the symbiont, or whether it has healing properties. The script of the episode states: "Odan takes a device from the counter, aims it toward the bulbous protuberance, and envelops it in a spray of light. The growth throbs there for a moment, then begins to recede again. Whatever it is, Odan has just fed it, and it is content once more."
While telling Doctor Bashir about her hunt for Rao Vantika in Deep Space 9's stasis room in 2369, Ty Kajada took this VISOR-like medical device before she decided to stab Rao Vantika with the sharpened device. (DS9: "The Passenger")