Hospital workers who operate X-ray equipment and related high-tech machinery say staffing shortages are worsening in their field, partly because people seeking careers are unaware of the opportunities.

"A lot of people - when they think about careers in health care - think `doctors and nurses,"' said Arlene Adler, a radiology educator who met over the weekend with other members of a coalition called the Summit on Manpower.The Summit, which comprises 18 groups including the American College of Radiology and the American Hospital Association, says 3 percent to 15 percent of hospital positions for X-ray technologists are going unfilled.

For nuclear medicine technologists, who use radioactive drugs to take pictures of the body, vacancy rates also range from 3 percent to 15 percent.

For radiation therapy technologists, the rates are higher, 5 percent to 21 percent. And for sonographers, rates are 4 percent to 17 percent.

Government studies indicate that radiological and related technology jobs will be among the top 10 in demand by 2000, said Ms. Adler, director of the Radiologic Technology Program at Indiana University Northwest in Gary.

Radiology and sonography positions usually require two years of course work after high school.

Chris Hornback, an X-ray technologist in Chicago Heights, said starting annual pay is $24,000 to $26,000, and after five years can range from $33,000 to $35,000. About 600 programs exist for radiological technology training, and 100 programs exist for each of the other fields, Ms. Adler said.