A band of rebel shareholders has sought to overturn the board of imaging tech Optiscan (ASX:OIL) – the second in as many weeks.

The group of 17, who together hold about 14 per cent of the stock, last night sent a notice to the company, seeking to remove director Ian Mann and appoint two others in his place.

The move follows an earlier notice by a group of four, including recently departed CEO Archie Fraser – seeking to remove the other remaining directors and appoint Mr Fraser to the board.

Mr Fraser left the company in January, but yet there has been no replacement found to take his place. Chairman Alan Hoffman is serving as executive chairman in the meantime.

His departure saw the share price drop below 10c. The shares were down 3 per cent on Tuesday morning to 7c.

The discontent comes despite the company describing its mid-year results as pleasing.

It reported a 186 per cent increase in revenue – booking $913,431 for the half-year and a loss of $1 million.

The chairman told shareholders he expected to achieve several key commercialisation milestones of its core technology that promises to revolutionise the world of surgery and biological research.