Up until the mid-24th century, the Dinaali were a dying species plagued with eco-disasters and famine, and a medical service that didn't treat the people it needed to. So the Dinaali government asked the Jye to intervene, a species known for their administrative abilities, and they reorganized the Dinaali medical system.
In 2377, The Doctor was kidnapped by Gar and sold to a Dinaali medical ship. While there, he tried to "re-allocate" some medication so that the amount of medication a person received was based on how badly they needed it, not how "useful to society" they were. (VOY: "Critical Care")
The Dinaali script had been developed by Geoffrey Mandel during production of a previous episode. In it's application as the Dinaal language, it "was inspired by crossword puzzles and was designed to be read both horizontally and vertically," with certain visual readouts intended to resemble thermometers.
Medical animations intended to represent Dinaali patients utilized anatomical graphics borrowed from image libraries, including skulls, spines and hearts, which were then "doctored to look alien."