TY - GEN
T1 - PET and SPECT dual-tracer imaging
T2 - 2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC
AU - Ma, Tianyu
AU - Shao, Yiping
AU - Yao, Rutao
AU - Manchiraju, Phani
PY - 2007
Y1 - 2007
N2 - This work was part of the feasibility study of performing simultaneous PET and SPECT imaging with a microPET scanner. SPECT data were acquired with slit-slat collimation by inserting a slit-slat collimator into microPET's detector ring but were contaminated by 511 keV photons' down-scattered events from PET tracer. In this study, contribution of down-scattered events in Tc-99m energy window (135-145 keV) was characterized through Monte Carlo simulation and measurements. With relative ratio of Tc-99m and F-18 activity being 1:1, ratio of recorded events from Tc-99m and F-18 source was 1:18.31. Nevertheless, simulation results revealed that the majority of down-scattering effects occurred in the detector crystals and thus were less object dependent. We investigated two subtraction-based compensation methods. The first method used an auxiliary energy window (AEW) and the second method employed extra shielding measurement (ESM) to acquire down-scatter- only data. Simulated and experimental studies showed improved image quality after applying the correction methods. With the activity ratio of SPECT tracer to PET tracer being 5:1, good SPECT images were obtained after correction, which were comparable to those from pure SPECT imaging.
AB - This work was part of the feasibility study of performing simultaneous PET and SPECT imaging with a microPET scanner. SPECT data were acquired with slit-slat collimation by inserting a slit-slat collimator into microPET's detector ring but were contaminated by 511 keV photons' down-scattered events from PET tracer. In this study, contribution of down-scattered events in Tc-99m energy window (135-145 keV) was characterized through Monte Carlo simulation and measurements. With relative ratio of Tc-99m and F-18 activity being 1:1, ratio of recorded events from Tc-99m and F-18 source was 1:18.31. Nevertheless, simulation results revealed that the majority of down-scattering effects occurred in the detector crystals and thus were less object dependent. We investigated two subtraction-based compensation methods. The first method used an auxiliary energy window (AEW) and the second method employed extra shielding measurement (ESM) to acquire down-scatter- only data. Simulated and experimental studies showed improved image quality after applying the correction methods. With the activity ratio of SPECT tracer to PET tracer being 5:1, good SPECT images were obtained after correction, which were comparable to those from pure SPECT imaging.
UR - http://www.scopus.com/inward/record.url?scp=48349094119&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=48349094119&partnerID=8YFLogxK
U2 - 10.1109/NSSMIC.2007.4436861
DO - 10.1109/NSSMIC.2007.4436861
M3 - Conference contribution
AN - SCOPUS:48349094119
SN - 1424409233
SN - 9781424409235
T3 - IEEE Nuclear Science Symposium Conference Record
SP - 3404
EP - 3407
BT - 2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC
Y2 - 27 October 2007 through 3 November 2007
ER -