The 25 p stamp shows an ultrasound image the 35p stamp shows a magnetic resonance image and the 41p stamp shows an X-ray CT image.
P - definition of p by The Free Dictionary. It usually signifies one of the following. P definition softly def. The 25 p stamp shows an ultrasound image the 35p stamp shows a magnetic resonance image and the 41p stamp shows an X-ray CT image.