- "See, my little gizmo lights up green to indicate pregnancy."
- "I thought it lights up green to indicate flesh wounds."
- "Yeah also that."
- —Doc in The Arrival
The Medical Scanner is a tool primarily used by Doc, and other medics, in order to diagnose the illnesses and injuries of the various soldiers he encounters, often the main cast. The device apparently requires a trained professional to use, though this is only because of its poor design rather than requiring any real skill as its only response to a wide assortment of medical problems is to glow different shades of green.
When Doc explains to an incredulous Church that Tucker is pregnant, he claims he knows this because the scanner glowed green. Church rebukes him, claiming the device glows green for flesh wounds and other problems, to which Doc admits it does this "for just about everything," but also states that it depends on the kind of green. The device also seems capable of diagnosing psychological problems as Doc states that one shade of green indicates rage "stemming from suppressed feelings of inadequacy," when pointing it at Church.
In later seasons, the medical scanner is shown to also have the ability to treat injuries, as Doc uses the device to tend Donut's and Felix's injuries in Season 11. Also in Revelation, Simmons uses Doc's medical scanner to fire an overcharged burst of energy by overloading the device's power-cell, suggesting it can easily be changed into a weapon. Medical scanners are also used by the Rebel Medic and Emily Grey of the New Republic and Federal Army of Chorus respectively during Season 12.
In Blue vs Blue, Doc reveals that the medical scanner he uses isn't a medical scanner, but rather an alien pistol. Whether this applies to all medical scanners seen in the series, or this just applies to him remains unknown.
- The medical scanner's model is that of a Covenant plasma pistol.
- In The Arrival, it's stated the device is quite dangerous to use, as Doc claims that another shade of green causes impotency, and apologizes to Church, as he was pointing it at him at the time. Church seems okay with this, stating in a rather depressed manner that he "wasn't using it anyway."