A new clinical method to quantify LCMRGlc with PET/FDG

Objectives To Quantify LCMRGlc with PET/FDG for clinical applications.

Methods Based on the Patlak approach, we propose a new approach for quantifying LCMRGlc with PET/FDG. The method uses two TTACs from two different regions and is noninvasive. The relative net FDG clearance rK can be estimated, and by removing global effect the functional images of LCMRGlc can be produced pixel-by-pixel quickly. FDG is commonly used for diagnosis of brain and other disease. The accuracy depends on whether and how the PET data is quantified to the physiologic value, so this method can also be used for the daily clinical diagnosis instead of using tissue radio activity or SUV. A set of dynamic FDG PET data acquired from a normal volunteer was used to validate this method. Dynamic emission scans (4 x 0.5min, 4 x 2min, 10 x 5min) were initiated simultaneously with an IV injection of 155MBq FDG. Arterial blood samples were collected via a catheter in the radial artery during the scans.

Results To compare three calculations of rK with original Patlak, our method and SUV,the linear regress was carried out , where y, x are two rK values calculated with Patlak and ours or SUV.We found the difference between Patlak and ours was much smaller than that between Patlak and SUV whichever part of brain was used as reference region. After removing global effect three images of LCMRGlc with above methods were obtained. We also found the image with ours was very similar to that with Patlak, while the difference between images with SUV and Patlak was quit big(seeSupporting Data).

Conclusions This real data study shows that our method is a good approximation to Patlak method and can be used to generate quantified LCMRGlc image in clinical application instead of SUV partly.

Research Support This work was supported by National Basic Research Subject of China (2006CB705705).