Minimum detectable defect thickness in SPECT myocardial perfusion test: phantom study with (99m)Tc and (201)Tl.
OBJECTIVE
The purpose of this study was to determine experimentally the minimum thickness (D(min)) of a defect inserted on the myocardial wall of a cardiac phantom at different locations that could be clearly detected in a SPECT perfusion study using (99m)Tc and (201)Tl.


METHODS
Rectangular (or cylindrical) defects with the same thickness were inserted on the inner surface of a myocardial phantom at 5 different locations: anterior (ANT), septal (SEP), inferoposterior (IP), lateral (LAT), and apical (AP). For different defect thickness (from 1 to 7 mm, in increments of 1 mm) the myocardial SPECT perfusion study was performed with (99m)Tc and (201)Tl using the same protocol that we use for patients. Baseline studies (with no defect inserted) were also performed. The SPECT images of the myocardial phantom with defects were compared with baseline SPECT images to determine whether the defect could be clearly identified.


RESULTS
The uniformity of the baseline SPECT images was analyzed very carefully where an IP artifact was detected. The D(min) was determined for (99m)Tc and (201)Tl at 3 radii of rotation: 21.0, 25.0, and 29.2 cm.


CONCLUSIONS
To be detected on SPECT images, a defect must be of a thickness > or =D(min). A simple method for performing a quality control test for SPECT nuclear cardiology can be developed based on these findings.
Elkamhawy
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Nuclear Medicine, Department of Radiology, Cuero Community Hospital, Cuero, Texas 77954, USA. abdel@dewittec.net
Chandna
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H
D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D009206:Myocardium / Q000473:pathology; D019047:Phantoms, Imaging; D013667:Technetium; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
D013794:Thallium Radioisotopes; D013667:Technetium