Assessment of Relative Kidney Function in KOREA NUCLEAR Medicine Study Evaluation of the Effectiveness of Geometric Mean According to Kidney Depth

Abstract

When measuring relative renal function ratio(RRFR) in nuclear medicine tests, radiation is usually counted us-ing a posterior detector. However, when there is a difference in the depth of the left and right kidneys, counting of the radiation using only the posterior detector may result in a lower counting rate of the deeply located kidneys. In this study, we investigated the usefulness of geometric mean in measuring the RRFR by applying a geometric mean after counting radiation using the anterior-posterior detector when the depths of the left and right kidneys are different. Kidney model studies and clinical studies were performed using the Symbia T16 gamma camera system to ob-tain anterior and posterior images. For RRFR calculations, RRFR was measured by applying arithmetic mean, once with information only counted by the posterior detector. Again, with the information counted by the anterior and posterior detectors, the geometric mean was applied to measure the RRFR. The results of the kidney model study were y = 0.23 + 0.38x, R2 = 0.986(p = 0.000), and the clinical results were y = 0.25 + 0.16x and R2 = 0.823(p = 0.000). It can be seen that as the depth difference of the elongation increases, the function ratio of the deeply located elongation increases gradually among the RRFRs in which the geometric mean is applied with the information counted by the anterior and posterior detectors. In kidney examinations conducted by the nuclear medicine department, the RRFR is generally measured using only the posterior detector. However, when the RRFR was measured using the geometric mean with the infor-mation from the anterior and posterior detectors, it was confirmed that the function ratio of the deeply located kidney rises. The above results suggest that the attenuation between the kidney and the detector is corrected. For patients with different depths of the left and right kidneys, it would be useful to measure the RRFR by applying a geometric mean with the both detectors.