X-ray production in the fluoroscopic mode must be controlled by a device which requires continuous pressure by the fluoroscopist for the entire time of any exposure. When recording serial fluoroscopic images, the fluoroscopist must be able to terminate the X-ray exposure at any time, but means may be provided to permit completion of any single exposure of the series in process.
Nev. Admin. Code § 459.568
NRS 459.201