Emergency Medical Hologram Mark VI

### Development Background

The Emergency Medical Holographic program (EMH) was a sophisticated hologram developed in the early 2370s by Starfleet and used on most Federation starships in the late 24th century. It was designed to provide short-term advanced assistance during emergencies in sickbay to the extent of literally replacing a starship's medical officer. (DS9: "Doctor Bashir, I Presume"). The formal name of the program was EMH Program AK-1 Diagnostic and Surgical Subroutine Omega-323. As of 2377, there have been four versions of the EMH, called Mark I, II, III, and IV.

Starfleet commissioned the brilliant holo-programmer Doctor Lewis Zimmerman at the Jupiter Station Holoprogramming Center as the embodiment of modern medicine. The EMH Mark I was first activated in 2371, and was programmed with over 5 million possible treatments from the collective information of 2000 medical references and the experience of 47 individual medical officers. The EMH was also supplemented with contingency programs and adaptive programs to learn while serving as a supplement of a normal medical staff in cases of emergency. It contains 50 million gigaquads of computer memory, which is "considerably more than most highly developed humanoid brains."

Dr. Zimmerman, proud at his achievement, decided to program the EMH with both his physical, and most notably, psychological likeness. Unfortunately, Dr. Zimmerman did not take into account that his own personality made a poor bedside manner for a medical doctor. The resulting hologram was arrogant and irritable, and as a result was poorly received by many Starfleet doctors. This resulted in nicknames like "Emergency Medical Hotheads" and "Extremely Marginal Housecalls."

Starfleet would later request Dr. Zimmerman to design a holoprogram to operate as a full-time doctor in any posting where life support or living space was at a premium and the primary mission did not require the doctor to leave sickbay. As a result, the research and design for the Long-term Medical Holographic program was begun in mid-2373.

Eventually it was concluded that the EMH Mark I was defective, and they were bounced out of the medical corps. While an ashamed Dr. Zimmerman tried to have them decommissioned, Starfleet reassigned them to scrub plasma conduits on waste transfer barges. Later the Mark I's were also deployed in other menial tasks, like dilithium mining.

Most notably The Doctor, a Mark I serving on the USS Voyager, ran almost continuously for years and was forced to expand his programming extensively to keep up. This EMH originally objected to being the replacement for the entire medical staff, as the EMH program was only meant to function for a maximum of 1,500 hours (62.5 days); after this time, memory degradation would occur.

Fortunately, with the help of his colleagues, his program was altered to overcome this shortcoming While the Mark I's outward appearance was a copy of its inventor, a disillusioned Dr. Zimmerman changed the outward appearance of the Mark II. Furthermore, the patterns of behavior of the following versions were designed to be more pleasant and courteous. To achieve this, Zimmerman initially tried to improve on the programming of the Mark I, but eventually decided to create the Mark II from scratch. In addition to that, new ship designs like the USS Prometheus enabled full mobility for the EMH, as the whole ship was outfitted with holographic projectors.

By 2377, the Mark II had been replaced by a Mark III, followed by a Mark IV

Technical Details

Holodecks used omnidirectional holographic diodes. A sickbay was fitted with a system of OHDs that projected an image of the EMH. Each projected a complete image. Visible portions changed as the hologram moved, creating an illusion of fluid motion.

Magnetic containment fields allowed the EMH to interact with physical objects. These force fields moved as the EMH moved to create the appearance of solid matter. The containment fields could be shut off, allowing objects and people to pass through them – an EMH's cohesion could range from solid to intangible.

When OHDs and magnetic field generators were added to other parts of a ship, they allowed the hologram to leave sickbay (as in more advanced Starfleet ships or modified configurations). Without these additional projectors, the EMH could only function in sickbay and the holodeck. The universal translator algorithm was written into the EMH's matrix. When he was first activated, the Voyager EMH apparently did not have the ability to deactivate himself after he finished his duties. However, he was later given that ability by issuing computer command "Override Command 1-EMH-Alpha; End Program".