Stress thallium-201/rest technetium-99m sequential dual isotope high-speed myocardial perfusion imaging.
OBJECTIVE
Our purpose was to describe a novel, rapid stress thallium-201 (Tl-201)/rest technetium-99m (Tc-99m) agent myocardial perfusion imaging (MPI) protocol (Tl/Tc) with a high-speed MPI scanner and to compare this protocol with a standard rest/stress Tc-99m agent protocol (Tc/Tc) with respect to image quality and radiation dosimetry.


BACKGROUND
Recent advances in gamma camera technology have provided opportunity for improved SPECT MPI protocols. A rapid Tl/Tc protocol that could improve image information while maintaining a low radiation burden for the patient would be desirable.


METHODS
We compared high-speed SPECT MPI studies in 374 consecutive patients undergoing exercise or pharmacologic Tl/Tc protocol to those of 262 patients undergoing rest/stress Tc/Tc protocol.


RESULTS
Tl/Tc imaging was accomplished in <20 min. Overall image quality was good to excellent in 96% and 98% of patients with the Tl/Tc and the Tc/Tc protocols, respectively (p = ns). Beginning rest imaging within 2 min after rest injection with the Tl/Tc protocol did not result in reduced confidence in image interpretation. Early rest Tc images of the Tl/Tc protocol showed less extracardiac activity than was observed on standard rest imaging used in the Tc/Tc protocol (84% vs. 61%), respectively (p < 0.01). The normalcy rate was high in both groups (100% vs. 92%). Radiation burden was similar between the Tl/Tc and Tc/Tc protocols.


CONCLUSIONS
A rapid stress Tl-201/rest Tc-99m protocol for use with high-speed SPECT MPI has image quality and radiation dosimetry similar to those observed with a conventional rest/stress Tc-99m protocol. The Tl/Tc protocol offers promise as an efficient and relatively low radiation dose method, in which the superior qualities of Tl-201 for stress imaging and of the Tc-99m agents for rest imaging can be preserved. The findings also suggest that with rapid imaging rest MPI immediately after Tc-99m agent injection may be superior to standard delayed image initiation.
Department of Imaging (Division of Nuclear Medicine), Cedars-Sinai Medical Center, Los Angeles, California 90048, USA. bermand@cshs.org
Daniel S
DS
Berman
Xingping
X
Kang
Balaji
B
Tamarappoo
Arik
A
Wolak
Sean W
SW
Hayes
Ryo
R
Nakazato
Louise E J
LE
Thomson
Faith
F
Kite
Ishac
I
Cohen
Piotr J
PJ
Slomka
Andrew J
AJ
Einstein
John D
JD
Friedman
D000241:Adenosine; D000368:Aged; D005080:Exercise Test; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine