Abstract
1669
Objectives: Assessing the relative function of each of three kidneys in patients having undergone kidney transplant using nuclear scintigraphy with standard planar imaging is problematic because of the different photon attenuation factors associated with native versus transplanted kidneys. To address this, we developed a method to correct for the attenuation of 140 keV photons based on measurements made on cross-sectional anatomical images. We performed a validation of the method using SPECT/CT.
Methods: Ten Tc-99m-MAG3 renal scans were obtained from 6 patients using either a conventional dual-headed gamma camera or, for 3 of 10, a Philips Precedence SPECT/CT scanner where a SPECT acquisition followed the dynamic study. For all studies, recent cross-sectional abdominal images were available. Maximum and minimum kidney depth was measured on concurrently-acquired (SPECT/CT) or recent anatomical images and used to derive an attenuation correction factor that we applied to the background-subtracted activity in the renogram.
Results: The relative total native kidney (left plus right) function ranged between 1% to 35% of total renal function in uncorrected scans and 1% to 45% in corrected scans. Correcting for attenuation had the greatest effect on the assessment of relative function in patients with significant residual native function.
Conclusions: Attenuation correction through measurements made on anatomical images, preferably obtained concurrently using a hybrid SPECT/CT scanner, improves the accuracy of functional measurements in renal scintigraphy.
- Society of Nuclear Medicine, Inc.