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Positron emission tomography (PET) is currently performed using either a dedicated PET scanner or scintillation gamma camera equipped with electronic circuitry for coincidence detection of 511 keV annihilation quanta (gamma camera PET system). Although the resolution limits of these two instruments are comparable, the sensitivity and count rate performance of the gamma camera PET system are several times lower than that of the PET scanner. Most gamma camera PET systems are manufactured as dual-detector systems capable of performing dual-head coincidence imaging. One possible step towards the improvement of the sensitivity of the gamma camera PET system is to add another detector head. This work investigates the characteristics of one such triple-head gamma camera PET system capable of performing triple-head coincidence imaging. The following performance characteristics of the system were assessed: spatial resolution, sensitivity, count rate performance. The spatial resolution, expressed as the full width at half-maximum (FWHM), at 1 cm radius is 5.9 mm ; at 10 cm radius, the transverse radial resolution is 5.3 mm, whilst the transverse tangential and axial resolutions are 8.9 mm and 13.3 mm, respectively. The sensitivity for a standard cylindrical phantom is 255 counts.s(-1).MBq*(-1)), using a 30% width photopeak energy window. An increase of 35% in the PET sensitivity is achievable by opening an additional 30% width energy window in the Compton region. The count rate in coincidence mode, at the upper limit of the systems optimal performance, is 45 kc.s(-1) (kc=kilocounts) using the photopeak energy window only, and increases to 60 kc.s(-1) using the photopeak + Compton windows. Sensitivity results are compared with published data for a similar dual-head detector system.

Positron emission tomography (PET) is currently performed using either a dedicated PET scanner or scintillation gamma camera equipped with electronic circuitry for coincidence detection of 511 keV annihilation quanta (gamma camera PET system). Although the resolution limits of these two instruments are comparable, the sensitivity and count rate performance of the gamma camera PET system are several times lower than that of the PET scanner. Most gamma camera PET systems are manufactured as dual-detector systems capable of performing dual-head coincidence imaging. One possible step towards the improvement of the sensitivity of the gamma camera PET system is to add another detector head. This work investigates the characteristics of one such triple-head gamma camera PET system capable of performing triple-head coincidence imaging. The following performance characteristics of the system were assessed: spatial resolution, sensitivity, count rate performance. The spatial resolution, expressed as the full width at half-maximum (FWHM), at 1 cm radius is 5.9 mm ; at 10 cm radius, the transverse radial resolution is 5.3 mm, whilst the transverse tangential and axial resolutions are 8.9 mm and 13.3 mm, respectively. The sensitivity for a standard cylindrical phantom is 255 counts×s71×MBq71, using a 30% width photopeak energy window. An increase of 35% in the PET sensitivity is achievable by opening an additional 30% width energy window in the Compton region. The count rate in coincidence mode, at the upper limit of the systems optimal performance, is 45 kc×s71 (kc=kilocounts) using the photopeak energy window only, and increases to 60 kc×s71 using the photopeak + Compton windows. Sensitivity results are compared with published data for a similar dualhead detector system.

Positron emission tomography (PET) is currently performed using either dedicated PET scanner or gamma camera equipped with electronic circuitry for coincidence detection of 511 keV annihilation quanta (gamma camera PET system). While resolution limits of these two instruments are comparable, sensitivity and count rate performance of the gamma camera PET system is several times lower than that of the PET scanner. Most gamma camera PET systems are manufactured as dual-detector systems capable of performing dual-head coincidence imaging. This work investigates performance characteristics of triple-head gamma camera PET system and compares them with 2-head system. Following performance characteristics of the system were assessed: spatial resolution, sensitivity, count rate performance. Spatial resolution, expressed as full-width-at-half-maximum (FWHM), at 1 cm radius is 5.9 mm ; at 10 cm radius transverse radial resolution is 5.3 mm while transverse tangential and axial resolution are 8.9 mm and 13.3 mm respectively. Sensitivity for standard cylindrical phantom is 255 c×s-1×MBq-1, cşcounts, using 30%-width photopeak energy window. Increase of 35 % in the PET sensitivity is achievable by opening an additional 30%-width energy window in the Compton region. Count rate in coincidence mode, at the upper limit of system&#8217 ; s optimal performance, is 45 kc×s-1 using only photopeak energy window, and increases to 60 kc×s-1 when using photopeak + Compton windows. Resolution when imaging cold phantom objects (rods and spheres) is 10 mm. In conclusion, our triple-head gamma camera PET system has system sensitivity two times higher in comparison with a similar dual-head system. Spatial resolution is in the same range as in the most dual-head systems.