Diasonics

Diasonics is a type of medical procedure, a diagnostic technique used aboard Federation starships in the 23rd century.

History
In 2273, Doctor Christine Chapel used diasonics as a method to diagnose Zantra, a long-lived Zaranite who had collapsed with heart failure while chatting in the recreation room with James T. Kirk and Spock aboard the USS Enterprise (NCC-1701). In sickbay, Chapel tried many other diagnostic procedures, including a Kirlian scan, but none explained the cause of the symptoms. 

Background

 * Diasonics was the name of a real-world company that manufactured ultrasound equipment.