The Comparison of Radiation Attenuation Correction Techniques for Relative Renal Function in Renal Cortical Scintigraphy

Background: Renal cortical scintigraphy using Tc-99m Dimercaptosuccinic acid (Tc-99m DMSA) is the detection of cortical abnormalities. In addition, relative renal function (RRF) is performed by DMSA scintigraphy and estimated from the radiopharmaceutical uptake in both kidneys with radiation attenuation correction. Generally, attenuation correction is calculated from mathematic methods with kidney depth correction for an accurate renal function value. Objective: The purpose of this research was to study the correlation of the RRF with radiation attenuation correction by geometric mean (GM) method and kidney depth correction by Beer-Lambert law equation. Methods: Researchers studied in the spherical phantom, kidney phantom and patient’s data using planar images from gamma camera imaging to evaluate the RRF. All study, the renal region of interest (ROI) is created from planar image for activity counts calculation. Results: The results are subtracted background and corrected the radiation attenuation using GM and kidney depth correction by Beer-Lambert law. Phantom studies, the RRF from GM radiation attenuation correction was consistent with kidney depth correction by Beer-Lambert law equation and true renal depth (ICC > 0.84). The patient’s study showed the RRF from GM method related to the other kidney depth correction methods (R2 > 0.95) and GM method was not significantly different from other renal depth correction methods (P > 0.05, ICC > 0.95). Conclusion: Finally, radiation attenuation is corrected by GM and kidney depth correction by Beer-Lambert law equation method can be used to estimate RRF appropriately in renal cortical scintigraphy.