Printed sources for positron emission tomography (PET)

We have developed a method that allows manufacturing of ¹⁸F radioactive printed sources using a standard ink-jet printer. Although previously used in printing and imaging single gamma emitter sources, such techniques have not been, to our knowledge, applied to the manufacturing of positron emitting sources. The added complication in the latter instance is a nonzero positron range and, thus, the need for some attenuating material surrounding the positron emitting atoms. The point sources were first imaged on a phosphor imager and then scanned on three different tomographs (Siemens/CTI ECAT 953B, CPS high-resolution research tomograph (HRRT) and Concorde microPET R4) to measure their point spread functions (PSFs). Where appropriate, the resolution agrees with published values. A comparison of the full width and tenth width half maxima of the point source profiles obtained with and without additional attenuating material showed no effect of the additional attenuation material on their values. The presence of the attenuating material however increased the number of counts in the point source image several fold due to a larger fraction of the positrons annihilating in the region close to the printed source. The results show that printed sources either on paper alone or on paper sandwiched between some additional attenuating material provide a practical means to obtain positron emitting sources.