Performance comparison of four commercial GE discovery PET/CT scanners: a monte carlo study using GATE

Combined PET/CT scanners now play a major role in medicine for in vivo imaging in oncology, cardiology, neurology, and psychiatry. As the performance of a scanner depends not only on the scintillating material but also on the scanner design, with regards to the advent of newer scanners, there is a need to optimize acquisition protocols as well as to compare scanner performances on an objective basis. In this study we evaluate and compare the performance of 4 Commercial GE PET/CT cameras, the [i] BGO-based Discovery ES PET/CT [DLS], [ii] the BGO-based Discovery ST PET/CT [DST], [iii] the BGO-based Discovery STE PET/CT [DSTE] and finally [iv] the EYSO-based Discovery RX PET/CT [DRX] scanner using the Geant4 Application for Tomographic Emission [GATE]. GATE is an open source Monte Carlo simulation platform developed for PET and SPECT studies and is supported by the OpenGATE collaboration. In accordance with the National Electrical Manufactures Association [NEMA] NU 2-2001 protocols, the validation of models is carried out against actual published measurements and the performance comparison is done for sensitivity, scatter fraction and count rate performance, showing very similar performance compared with published results, thus enabling investigations to better model system performance [e.g. resolution degradation] within the reconstruction task.. The simulated results demonstrate highest sensitivity performance with the DST [though with the highest scatter fraction], and highest NECR performance for the EYSO-based DRX, The results also show that DRX, DES and DSTE PET/CT cameras have nearly the same amount of scatter fraction

novel dual energy CT-based attenuation correction method in PET/CT systems: a phantom study

In present PET/CT scanners, PET attenuation correction is performed by relying on the information given by CT scan. In the CT-based attenuation correction methods, dual-energy technique [DECT] is the most accurate approach, which has been limited due to the increasing patient dose. In this feasibility study, we have introduced a new method that can implement dual-energy technique with only a single energy CT scan. The implementation was done by CT scans of RANDO phantom at tube voltages of 80 kV[P] and 140 kV[P]. The acquired data was used to obtain conversion curves [which scale CT numbers at different kV[P] to each other], in three regions including lung tissue [HU<-100], soft tissue [-100200] for the combination of 80 kV[P] /140 kV[P]. Therefore, with having the CT image in one energy, we generate the CT image at the second energy [from now we call it virtual dual-energy technique] using these kV[P] conversion curves. The attenuation map at 511 ke[V] was generated using bilinear [the most commonly used method in commercially available PET/CT scanners], real dual-energy and virtual dual-energy technique in a polyethylene phantom. In the phantom study, the created attenuation map using mentioned methods are compared to the theoretical values calculated using XCOM cross section library. The results in the phantom data show 10.1%, 4.2% and 4.3% errors for bilinear, dual-energy and virtual dual-energy techniques respectively. Further evaluation using a larger patient data is underway to evaluate the potential of the technique in a clinical setting