Minimum detectable defect thickness in SPECT myocardial perfusion test: phantom study with (99m)Tc and (201)Tl

Area of Science:

• Nuclear Medicine
• Cardiovascular Imaging
• Medical Physics

Background:

• Myocardial perfusion imaging using SPECT is a key diagnostic tool.
• Accurate detection of myocardial defects depends on imaging parameters and defect characteristics.
• Establishing minimum detectable defect size is essential for quality control.

Purpose of the Study:

• To experimentally determine the minimum myocardial defect thickness (D(min)) detectable by SPECT.
• To evaluate detection thresholds using both technetium-99m (99mTc) and thallium-201 (201Tl).
• To assess the influence of defect location on detection in cardiac phantom studies.

Main Methods:

• A cardiac phantom with myocardial defects of varying thicknesses (1-7 mm) was used.
• Defects were inserted at five distinct myocardial locations.
• SPECT perfusion studies were performed with 99mTc and 201Tl using standard clinical protocols.
• SPECT images were compared to baseline studies to identify detectable defects.

Main Results:

• The minimum detectable defect thickness (D(min)) was determined for both 99mTc and 201Tl.
• Detection thresholds varied depending on defect location and SPECT acquisition parameters (e.g., radius of rotation).
• An inferoposterior (IP) artifact was noted during baseline image analysis, highlighting potential imaging challenges.

Conclusions:

• Myocardial defects require a thickness greater than or equal to D(min) for clear detection on SPECT images.
• These findings enable the development of a quality control test for SPECT nuclear cardiology.
• Standardized quality control can improve the reliability of SPECT myocardial perfusion studies.