Radiographers based at Raigmore Hospital in Inverness have taken industrial action for the first time in more than 30 years.
They began a four-hour strike at 9am this morning, with the protest over pay continuing with a work-to-rule for the rest of the week.
The action follows a ballot by the Society of Radiographers, in which a majority of members, employed by the NHS, voted for strike action.
Drivers of several vehicles blasted their horns in support as they passed the picket line at the main entrance to Raigmore.
Emergency and urgent procedures will continue as normal, said one of the pickets, Stewart Murdoch, 29, from Inverness.
He added: “Our wages have fallen by the equivalent of 14% in the last five years and the recommendations of a pay review body, of an increase in line with inflation, have been rejected by the NHS.”