The effects of different correction techniques on absolute volume determination with SPECT using a threshold edge...

Area of Science:

• Nuclear Medicine
• Medical Imaging Physics

Background:

• Planar radionuclide imaging faces challenges in accurate organ quantitation due to overlying/underlying radioactivity.
• Single photon emission computerized tomography (SPECT) improves image contrast but is affected by photon attenuation and scatter.

Purpose of the Study:

• To investigate the impact of various SPECT image correction methods on threshold values used for organ volume quantitation.
• To determine how different correction techniques influence the accuracy of volume measurements.

Main Methods:

• Utilized a thorax phantom with volumes ranging from 30 to 1200 ml.
• Evaluated the effect of different scatter subtraction and attenuation correction methods on threshold values.
• Assessed volume quantitation accuracy using threshold techniques.

Main Results:

• Threshold values varied significantly, from 45.6% (210 ml, no correction) to 23.7% (1200 ml, combined scatter and attenuation correction).
• A negative correlation was observed between threshold value and organ volume.
• The most prominent reduction in threshold occurred with combined scatter and attenuation correction.

Conclusions:

• SPECT image correction methods, particularly for attenuation and scatter, directly influence the threshold values required for accurate volume quantitation.
• Employing a constant threshold value across different correction methods can lead to underestimation of larger organ volumes.