Characterization of176Lu background in LSO-based PET scanners.
LSO and LYSO are today the most common scintillators used in positron emission tomography. Lutetium contains traces of176Lu, a radioactive isotope that decays β-with a cascade of γ photons in coincidence. Therefore, Lutetium-based scintillators are characterized by a small natural radiation background. In this paper, we investigate and characterize the176Lu radiation background via experiments performed on LSO-based PET scanners. LSO background was measured at different energy windows and different time coincidence windows, and by using shields to alter the original spectrum. The effect of radiation background in particularly count-starved applications, such as90Y imaging, is analysed and discussed. Depending on the size of the PET scanner, between 500 and 1000 total random counts per second and between 3 and 5 total true coincidences per second were measured in standard coincidence mode. The LSO background counts in a Siemens mCT in the standard PET energy and time windows are in general negligible in terms of trues, and are comparable to that measured in a BGO scanner of similar size.
Siemens Healthcare Molecular Imaging, Knoxville, United States of America.
Maurizio
M
Conti
Lars
L
Eriksson
Harold
H
Rothfuss
Therese
T
Sjoeholm
David
D
Townsend
Göran
G
Rosenqvist
Thomas
T
Carlier
D001417:Background Radiation; D008187:Lutetium / Q000737:chemistry*; D017785:Photons; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000592:standards; D011868:Radioisotopes / Q000737:chemistry*; D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes
D011868:Radioisotopes; D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes; D008187:Lutetium