Digital imaging company ACD Systems International Inc. has announced the following changes to its board of directors and management: Doug Vandekerkhove has been appointed chairman of the board and maintains his position as CEO; Mike Zelen has been appointed president and continues in his role as CFO; Lee Richardson, former chairman of the board, will remain a director.   . . .   Seki Technotron will have exclusive rights to distribute Accent Optical Technologies' DIVA-Dynamic I(V) Analyzer in Japan, effective Dec. 4.   . . .   Hologic Inc., provider of medical imaging equipment for women's health and digital radiographic applications, has signed a three-year agreement with Novation for the purchase and sale of Hologic's digital radiographic systems.