Abstract: A method of producing a road-mapped image of a body portion for monitored guidance of a catheter therethrough, the method including providing a first X-ray transmission frame of the body portion, injecting contrast-enhancing material into a blood vessel in the body portion, irradiating the body portion with X-ray radiation for a first irradiation session, producing a series of second X-ray transmission frames of the body portion during the first irradiation session, forming a series of third, subtracted, frames each third frame corresponding to the difference between a respective second frame and the first frame, selecting one of the third frames, irradiating the body portion with X-ray radiation for a second irradiation session, guiding the catheter through a blood vessel in the body portion during the irradiation session, producing a first, dynamic, X-ray transmission image including a plurality of fourth frames of the body portion during the second irradiation session and forming a second, dynamic, image o